xref: /freebsd-src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
10b57cec5SDimitry Andric //===- SROA.cpp - Scalar Replacement Of Aggregates ------------------------===//
20b57cec5SDimitry Andric //
30b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
40b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
50b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
60b57cec5SDimitry Andric //
70b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
80b57cec5SDimitry Andric /// \file
90b57cec5SDimitry Andric /// This transformation implements the well known scalar replacement of
100b57cec5SDimitry Andric /// aggregates transformation. It tries to identify promotable elements of an
110b57cec5SDimitry Andric /// aggregate alloca, and promote them to registers. It will also try to
120b57cec5SDimitry Andric /// convert uses of an element (or set of elements) of an alloca into a vector
130b57cec5SDimitry Andric /// or bitfield-style integer scalar if appropriate.
140b57cec5SDimitry Andric ///
150b57cec5SDimitry Andric /// It works to do this with minimal slicing of the alloca so that regions
160b57cec5SDimitry Andric /// which are merely transferred in and out of external memory remain unchanged
170b57cec5SDimitry Andric /// and are not decomposed to scalar code.
180b57cec5SDimitry Andric ///
190b57cec5SDimitry Andric /// Because this also performs alloca promotion, it can be thought of as also
200b57cec5SDimitry Andric /// serving the purpose of SSA formation. The algorithm iterates on the
210b57cec5SDimitry Andric /// function until all opportunities for promotion have been realized.
220b57cec5SDimitry Andric ///
230b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
240b57cec5SDimitry Andric 
250b57cec5SDimitry Andric #include "llvm/Transforms/Scalar/SROA.h"
260b57cec5SDimitry Andric #include "llvm/ADT/APInt.h"
270b57cec5SDimitry Andric #include "llvm/ADT/ArrayRef.h"
280b57cec5SDimitry Andric #include "llvm/ADT/DenseMap.h"
295f757f3fSDimitry Andric #include "llvm/ADT/MapVector.h"
300b57cec5SDimitry Andric #include "llvm/ADT/PointerIntPair.h"
310b57cec5SDimitry Andric #include "llvm/ADT/STLExtras.h"
320b57cec5SDimitry Andric #include "llvm/ADT/SetVector.h"
330b57cec5SDimitry Andric #include "llvm/ADT/SmallBitVector.h"
340b57cec5SDimitry Andric #include "llvm/ADT/SmallPtrSet.h"
350b57cec5SDimitry Andric #include "llvm/ADT/SmallVector.h"
360b57cec5SDimitry Andric #include "llvm/ADT/Statistic.h"
370b57cec5SDimitry Andric #include "llvm/ADT/StringRef.h"
380b57cec5SDimitry Andric #include "llvm/ADT/Twine.h"
390b57cec5SDimitry Andric #include "llvm/ADT/iterator.h"
400b57cec5SDimitry Andric #include "llvm/ADT/iterator_range.h"
410b57cec5SDimitry Andric #include "llvm/Analysis/AssumptionCache.h"
42bdd1243dSDimitry Andric #include "llvm/Analysis/DomTreeUpdater.h"
430b57cec5SDimitry Andric #include "llvm/Analysis/GlobalsModRef.h"
440b57cec5SDimitry Andric #include "llvm/Analysis/Loads.h"
450b57cec5SDimitry Andric #include "llvm/Analysis/PtrUseVisitor.h"
460b57cec5SDimitry Andric #include "llvm/Config/llvm-config.h"
470b57cec5SDimitry Andric #include "llvm/IR/BasicBlock.h"
480b57cec5SDimitry Andric #include "llvm/IR/Constant.h"
490b57cec5SDimitry Andric #include "llvm/IR/ConstantFolder.h"
500b57cec5SDimitry Andric #include "llvm/IR/Constants.h"
510b57cec5SDimitry Andric #include "llvm/IR/DIBuilder.h"
520b57cec5SDimitry Andric #include "llvm/IR/DataLayout.h"
531fd87a68SDimitry Andric #include "llvm/IR/DebugInfo.h"
540b57cec5SDimitry Andric #include "llvm/IR/DebugInfoMetadata.h"
550b57cec5SDimitry Andric #include "llvm/IR/DerivedTypes.h"
560b57cec5SDimitry Andric #include "llvm/IR/Dominators.h"
570b57cec5SDimitry Andric #include "llvm/IR/Function.h"
580b57cec5SDimitry Andric #include "llvm/IR/GetElementPtrTypeIterator.h"
590b57cec5SDimitry Andric #include "llvm/IR/GlobalAlias.h"
600b57cec5SDimitry Andric #include "llvm/IR/IRBuilder.h"
610b57cec5SDimitry Andric #include "llvm/IR/InstVisitor.h"
620b57cec5SDimitry Andric #include "llvm/IR/Instruction.h"
630b57cec5SDimitry Andric #include "llvm/IR/Instructions.h"
640b57cec5SDimitry Andric #include "llvm/IR/IntrinsicInst.h"
650b57cec5SDimitry Andric #include "llvm/IR/LLVMContext.h"
660b57cec5SDimitry Andric #include "llvm/IR/Metadata.h"
670b57cec5SDimitry Andric #include "llvm/IR/Module.h"
680b57cec5SDimitry Andric #include "llvm/IR/Operator.h"
690b57cec5SDimitry Andric #include "llvm/IR/PassManager.h"
700b57cec5SDimitry Andric #include "llvm/IR/Type.h"
710b57cec5SDimitry Andric #include "llvm/IR/Use.h"
720b57cec5SDimitry Andric #include "llvm/IR/User.h"
730b57cec5SDimitry Andric #include "llvm/IR/Value.h"
745f757f3fSDimitry Andric #include "llvm/IR/ValueHandle.h"
75480093f4SDimitry Andric #include "llvm/InitializePasses.h"
760b57cec5SDimitry Andric #include "llvm/Pass.h"
770b57cec5SDimitry Andric #include "llvm/Support/Casting.h"
780b57cec5SDimitry Andric #include "llvm/Support/CommandLine.h"
790b57cec5SDimitry Andric #include "llvm/Support/Compiler.h"
800b57cec5SDimitry Andric #include "llvm/Support/Debug.h"
810b57cec5SDimitry Andric #include "llvm/Support/ErrorHandling.h"
820b57cec5SDimitry Andric #include "llvm/Support/raw_ostream.h"
830b57cec5SDimitry Andric #include "llvm/Transforms/Scalar.h"
84bdd1243dSDimitry Andric #include "llvm/Transforms/Utils/BasicBlockUtils.h"
85480093f4SDimitry Andric #include "llvm/Transforms/Utils/Local.h"
860b57cec5SDimitry Andric #include "llvm/Transforms/Utils/PromoteMemToReg.h"
870b57cec5SDimitry Andric #include <algorithm>
880b57cec5SDimitry Andric #include <cassert>
890b57cec5SDimitry Andric #include <cstddef>
900b57cec5SDimitry Andric #include <cstdint>
910b57cec5SDimitry Andric #include <cstring>
920b57cec5SDimitry Andric #include <iterator>
930b57cec5SDimitry Andric #include <string>
940b57cec5SDimitry Andric #include <tuple>
950b57cec5SDimitry Andric #include <utility>
965f757f3fSDimitry Andric #include <variant>
970b57cec5SDimitry Andric #include <vector>
980b57cec5SDimitry Andric 
990b57cec5SDimitry Andric using namespace llvm;
1000b57cec5SDimitry Andric 
1010b57cec5SDimitry Andric #define DEBUG_TYPE "sroa"
1020b57cec5SDimitry Andric 
1030b57cec5SDimitry Andric STATISTIC(NumAllocasAnalyzed, "Number of allocas analyzed for replacement");
1040b57cec5SDimitry Andric STATISTIC(NumAllocaPartitions, "Number of alloca partitions formed");
1050b57cec5SDimitry Andric STATISTIC(MaxPartitionsPerAlloca, "Maximum number of partitions per alloca");
1060b57cec5SDimitry Andric STATISTIC(NumAllocaPartitionUses, "Number of alloca partition uses rewritten");
1070b57cec5SDimitry Andric STATISTIC(MaxUsesPerAllocaPartition, "Maximum number of uses of a partition");
1080b57cec5SDimitry Andric STATISTIC(NumNewAllocas, "Number of new, smaller allocas introduced");
1090b57cec5SDimitry Andric STATISTIC(NumPromoted, "Number of allocas promoted to SSA values");
1100b57cec5SDimitry Andric STATISTIC(NumLoadsSpeculated, "Number of loads speculated to allow promotion");
111bdd1243dSDimitry Andric STATISTIC(NumLoadsPredicated,
112bdd1243dSDimitry Andric           "Number of loads rewritten into predicated loads to allow promotion");
113bdd1243dSDimitry Andric STATISTIC(
114bdd1243dSDimitry Andric     NumStoresPredicated,
115bdd1243dSDimitry Andric     "Number of stores rewritten into predicated loads to allow promotion");
1160b57cec5SDimitry Andric STATISTIC(NumDeleted, "Number of instructions deleted");
1170b57cec5SDimitry Andric STATISTIC(NumVectorized, "Number of vectorized aggregates");
1180b57cec5SDimitry Andric 
11906c3fb27SDimitry Andric /// Disable running mem2reg during SROA in order to test or debug SROA.
12006c3fb27SDimitry Andric static cl::opt<bool> SROASkipMem2Reg("sroa-skip-mem2reg", cl::init(false),
12106c3fb27SDimitry Andric                                      cl::Hidden);
1220b57cec5SDimitry Andric namespace {
12306c3fb27SDimitry Andric 
1245f757f3fSDimitry Andric class AllocaSliceRewriter;
1255f757f3fSDimitry Andric class AllocaSlices;
1265f757f3fSDimitry Andric class Partition;
1275f757f3fSDimitry Andric 
1285f757f3fSDimitry Andric class SelectHandSpeculativity {
1295f757f3fSDimitry Andric   unsigned char Storage = 0; // None are speculatable by default.
1305f757f3fSDimitry Andric   using TrueVal = Bitfield::Element<bool, 0, 1>;  // Low 0'th bit.
1315f757f3fSDimitry Andric   using FalseVal = Bitfield::Element<bool, 1, 1>; // Low 1'th bit.
1325f757f3fSDimitry Andric public:
1335f757f3fSDimitry Andric   SelectHandSpeculativity() = default;
1345f757f3fSDimitry Andric   SelectHandSpeculativity &setAsSpeculatable(bool isTrueVal);
1355f757f3fSDimitry Andric   bool isSpeculatable(bool isTrueVal) const;
1365f757f3fSDimitry Andric   bool areAllSpeculatable() const;
1375f757f3fSDimitry Andric   bool areAnySpeculatable() const;
1385f757f3fSDimitry Andric   bool areNoneSpeculatable() const;
1395f757f3fSDimitry Andric   // For interop as int half of PointerIntPair.
1405f757f3fSDimitry Andric   explicit operator intptr_t() const { return static_cast<intptr_t>(Storage); }
1415f757f3fSDimitry Andric   explicit SelectHandSpeculativity(intptr_t Storage_) : Storage(Storage_) {}
1425f757f3fSDimitry Andric };
1435f757f3fSDimitry Andric static_assert(sizeof(SelectHandSpeculativity) == sizeof(unsigned char));
1445f757f3fSDimitry Andric 
1455f757f3fSDimitry Andric using PossiblySpeculatableLoad =
1465f757f3fSDimitry Andric     PointerIntPair<LoadInst *, 2, SelectHandSpeculativity>;
1475f757f3fSDimitry Andric using UnspeculatableStore = StoreInst *;
1485f757f3fSDimitry Andric using RewriteableMemOp =
1495f757f3fSDimitry Andric     std::variant<PossiblySpeculatableLoad, UnspeculatableStore>;
1505f757f3fSDimitry Andric using RewriteableMemOps = SmallVector<RewriteableMemOp, 2>;
1515f757f3fSDimitry Andric 
1525f757f3fSDimitry Andric /// An optimization pass providing Scalar Replacement of Aggregates.
1535f757f3fSDimitry Andric ///
1545f757f3fSDimitry Andric /// This pass takes allocations which can be completely analyzed (that is, they
1555f757f3fSDimitry Andric /// don't escape) and tries to turn them into scalar SSA values. There are
1565f757f3fSDimitry Andric /// a few steps to this process.
1575f757f3fSDimitry Andric ///
1585f757f3fSDimitry Andric /// 1) It takes allocations of aggregates and analyzes the ways in which they
1595f757f3fSDimitry Andric ///    are used to try to split them into smaller allocations, ideally of
1605f757f3fSDimitry Andric ///    a single scalar data type. It will split up memcpy and memset accesses
1615f757f3fSDimitry Andric ///    as necessary and try to isolate individual scalar accesses.
1625f757f3fSDimitry Andric /// 2) It will transform accesses into forms which are suitable for SSA value
1635f757f3fSDimitry Andric ///    promotion. This can be replacing a memset with a scalar store of an
1645f757f3fSDimitry Andric ///    integer value, or it can involve speculating operations on a PHI or
1655f757f3fSDimitry Andric ///    select to be a PHI or select of the results.
1665f757f3fSDimitry Andric /// 3) Finally, this will try to detect a pattern of accesses which map cleanly
1675f757f3fSDimitry Andric ///    onto insert and extract operations on a vector value, and convert them to
1685f757f3fSDimitry Andric ///    this form. By doing so, it will enable promotion of vector aggregates to
1695f757f3fSDimitry Andric ///    SSA vector values.
1705f757f3fSDimitry Andric class SROA {
1715f757f3fSDimitry Andric   LLVMContext *const C;
1725f757f3fSDimitry Andric   DomTreeUpdater *const DTU;
1735f757f3fSDimitry Andric   AssumptionCache *const AC;
1745f757f3fSDimitry Andric   const bool PreserveCFG;
1755f757f3fSDimitry Andric 
1765f757f3fSDimitry Andric   /// Worklist of alloca instructions to simplify.
1775f757f3fSDimitry Andric   ///
1785f757f3fSDimitry Andric   /// Each alloca in the function is added to this. Each new alloca formed gets
1795f757f3fSDimitry Andric   /// added to it as well to recursively simplify unless that alloca can be
1805f757f3fSDimitry Andric   /// directly promoted. Finally, each time we rewrite a use of an alloca other
1815f757f3fSDimitry Andric   /// the one being actively rewritten, we add it back onto the list if not
1825f757f3fSDimitry Andric   /// already present to ensure it is re-visited.
1835f757f3fSDimitry Andric   SmallSetVector<AllocaInst *, 16> Worklist;
1845f757f3fSDimitry Andric 
1855f757f3fSDimitry Andric   /// A collection of instructions to delete.
1865f757f3fSDimitry Andric   /// We try to batch deletions to simplify code and make things a bit more
1875f757f3fSDimitry Andric   /// efficient. We also make sure there is no dangling pointers.
1885f757f3fSDimitry Andric   SmallVector<WeakVH, 8> DeadInsts;
1895f757f3fSDimitry Andric 
1905f757f3fSDimitry Andric   /// Post-promotion worklist.
1915f757f3fSDimitry Andric   ///
1925f757f3fSDimitry Andric   /// Sometimes we discover an alloca which has a high probability of becoming
1935f757f3fSDimitry Andric   /// viable for SROA after a round of promotion takes place. In those cases,
1945f757f3fSDimitry Andric   /// the alloca is enqueued here for re-processing.
1955f757f3fSDimitry Andric   ///
1965f757f3fSDimitry Andric   /// Note that we have to be very careful to clear allocas out of this list in
1975f757f3fSDimitry Andric   /// the event they are deleted.
1985f757f3fSDimitry Andric   SmallSetVector<AllocaInst *, 16> PostPromotionWorklist;
1995f757f3fSDimitry Andric 
2005f757f3fSDimitry Andric   /// A collection of alloca instructions we can directly promote.
2015f757f3fSDimitry Andric   std::vector<AllocaInst *> PromotableAllocas;
2025f757f3fSDimitry Andric 
2035f757f3fSDimitry Andric   /// A worklist of PHIs to speculate prior to promoting allocas.
2045f757f3fSDimitry Andric   ///
2055f757f3fSDimitry Andric   /// All of these PHIs have been checked for the safety of speculation and by
2065f757f3fSDimitry Andric   /// being speculated will allow promoting allocas currently in the promotable
2075f757f3fSDimitry Andric   /// queue.
2085f757f3fSDimitry Andric   SmallSetVector<PHINode *, 8> SpeculatablePHIs;
2095f757f3fSDimitry Andric 
2105f757f3fSDimitry Andric   /// A worklist of select instructions to rewrite prior to promoting
2115f757f3fSDimitry Andric   /// allocas.
2125f757f3fSDimitry Andric   SmallMapVector<SelectInst *, RewriteableMemOps, 8> SelectsToRewrite;
2135f757f3fSDimitry Andric 
2145f757f3fSDimitry Andric   /// Select instructions that use an alloca and are subsequently loaded can be
2155f757f3fSDimitry Andric   /// rewritten to load both input pointers and then select between the result,
2165f757f3fSDimitry Andric   /// allowing the load of the alloca to be promoted.
2175f757f3fSDimitry Andric   /// From this:
2185f757f3fSDimitry Andric   ///   %P2 = select i1 %cond, ptr %Alloca, ptr %Other
2195f757f3fSDimitry Andric   ///   %V = load <type>, ptr %P2
2205f757f3fSDimitry Andric   /// to:
2215f757f3fSDimitry Andric   ///   %V1 = load <type>, ptr %Alloca      -> will be mem2reg'd
2225f757f3fSDimitry Andric   ///   %V2 = load <type>, ptr %Other
2235f757f3fSDimitry Andric   ///   %V = select i1 %cond, <type> %V1, <type> %V2
2245f757f3fSDimitry Andric   ///
2255f757f3fSDimitry Andric   /// We can do this to a select if its only uses are loads
2265f757f3fSDimitry Andric   /// and if either the operand to the select can be loaded unconditionally,
2275f757f3fSDimitry Andric   ///        or if we are allowed to perform CFG modifications.
2285f757f3fSDimitry Andric   /// If found an intervening bitcast with a single use of the load,
2295f757f3fSDimitry Andric   /// allow the promotion.
2305f757f3fSDimitry Andric   static std::optional<RewriteableMemOps>
2315f757f3fSDimitry Andric   isSafeSelectToSpeculate(SelectInst &SI, bool PreserveCFG);
2325f757f3fSDimitry Andric 
2335f757f3fSDimitry Andric public:
2345f757f3fSDimitry Andric   SROA(LLVMContext *C, DomTreeUpdater *DTU, AssumptionCache *AC,
2355f757f3fSDimitry Andric        SROAOptions PreserveCFG_)
2365f757f3fSDimitry Andric       : C(C), DTU(DTU), AC(AC),
2375f757f3fSDimitry Andric         PreserveCFG(PreserveCFG_ == SROAOptions::PreserveCFG) {}
2385f757f3fSDimitry Andric 
2395f757f3fSDimitry Andric   /// Main run method used by both the SROAPass and by the legacy pass.
2405f757f3fSDimitry Andric   std::pair<bool /*Changed*/, bool /*CFGChanged*/> runSROA(Function &F);
2415f757f3fSDimitry Andric 
2425f757f3fSDimitry Andric private:
2435f757f3fSDimitry Andric   friend class AllocaSliceRewriter;
2445f757f3fSDimitry Andric 
2455f757f3fSDimitry Andric   bool presplitLoadsAndStores(AllocaInst &AI, AllocaSlices &AS);
2465f757f3fSDimitry Andric   AllocaInst *rewritePartition(AllocaInst &AI, AllocaSlices &AS, Partition &P);
2475f757f3fSDimitry Andric   bool splitAlloca(AllocaInst &AI, AllocaSlices &AS);
2485f757f3fSDimitry Andric   std::pair<bool /*Changed*/, bool /*CFGChanged*/> runOnAlloca(AllocaInst &AI);
2495f757f3fSDimitry Andric   void clobberUse(Use &U);
2505f757f3fSDimitry Andric   bool deleteDeadInstructions(SmallPtrSetImpl<AllocaInst *> &DeletedAllocas);
2515f757f3fSDimitry Andric   bool promoteAllocas(Function &F);
2525f757f3fSDimitry Andric };
2535f757f3fSDimitry Andric 
2545f757f3fSDimitry Andric } // end anonymous namespace
2555f757f3fSDimitry Andric 
25606c3fb27SDimitry Andric /// Calculate the fragment of a variable to use when slicing a store
25706c3fb27SDimitry Andric /// based on the slice dimensions, existing fragment, and base storage
25806c3fb27SDimitry Andric /// fragment.
25906c3fb27SDimitry Andric /// Results:
26006c3fb27SDimitry Andric /// UseFrag - Use Target as the new fragment.
26106c3fb27SDimitry Andric /// UseNoFrag - The new slice already covers the whole variable.
26206c3fb27SDimitry Andric /// Skip - The new alloca slice doesn't include this variable.
26306c3fb27SDimitry Andric /// FIXME: Can we use calculateFragmentIntersect instead?
2645f757f3fSDimitry Andric namespace {
26506c3fb27SDimitry Andric enum FragCalcResult { UseFrag, UseNoFrag, Skip };
2665f757f3fSDimitry Andric }
26706c3fb27SDimitry Andric static FragCalcResult
26806c3fb27SDimitry Andric calculateFragment(DILocalVariable *Variable,
26906c3fb27SDimitry Andric                   uint64_t NewStorageSliceOffsetInBits,
27006c3fb27SDimitry Andric                   uint64_t NewStorageSliceSizeInBits,
27106c3fb27SDimitry Andric                   std::optional<DIExpression::FragmentInfo> StorageFragment,
27206c3fb27SDimitry Andric                   std::optional<DIExpression::FragmentInfo> CurrentFragment,
27306c3fb27SDimitry Andric                   DIExpression::FragmentInfo &Target) {
27406c3fb27SDimitry Andric   // If the base storage describes part of the variable apply the offset and
27506c3fb27SDimitry Andric   // the size constraint.
27606c3fb27SDimitry Andric   if (StorageFragment) {
27706c3fb27SDimitry Andric     Target.SizeInBits =
27806c3fb27SDimitry Andric         std::min(NewStorageSliceSizeInBits, StorageFragment->SizeInBits);
27906c3fb27SDimitry Andric     Target.OffsetInBits =
28006c3fb27SDimitry Andric         NewStorageSliceOffsetInBits + StorageFragment->OffsetInBits;
28106c3fb27SDimitry Andric   } else {
28206c3fb27SDimitry Andric     Target.SizeInBits = NewStorageSliceSizeInBits;
28306c3fb27SDimitry Andric     Target.OffsetInBits = NewStorageSliceOffsetInBits;
28406c3fb27SDimitry Andric   }
28506c3fb27SDimitry Andric 
28606c3fb27SDimitry Andric   // If this slice extracts the entirety of an independent variable from a
28706c3fb27SDimitry Andric   // larger alloca, do not produce a fragment expression, as the variable is
28806c3fb27SDimitry Andric   // not fragmented.
28906c3fb27SDimitry Andric   if (!CurrentFragment) {
29006c3fb27SDimitry Andric     if (auto Size = Variable->getSizeInBits()) {
29106c3fb27SDimitry Andric       // Treat the current fragment as covering the whole variable.
29206c3fb27SDimitry Andric       CurrentFragment = DIExpression::FragmentInfo(*Size, 0);
29306c3fb27SDimitry Andric       if (Target == CurrentFragment)
29406c3fb27SDimitry Andric         return UseNoFrag;
29506c3fb27SDimitry Andric     }
29606c3fb27SDimitry Andric   }
29706c3fb27SDimitry Andric 
29806c3fb27SDimitry Andric   // No additional work to do if there isn't a fragment already, or there is
29906c3fb27SDimitry Andric   // but it already exactly describes the new assignment.
30006c3fb27SDimitry Andric   if (!CurrentFragment || *CurrentFragment == Target)
30106c3fb27SDimitry Andric     return UseFrag;
30206c3fb27SDimitry Andric 
30306c3fb27SDimitry Andric   // Reject the target fragment if it doesn't fit wholly within the current
30406c3fb27SDimitry Andric   // fragment. TODO: We could instead chop up the target to fit in the case of
30506c3fb27SDimitry Andric   // a partial overlap.
30606c3fb27SDimitry Andric   if (Target.startInBits() < CurrentFragment->startInBits() ||
30706c3fb27SDimitry Andric       Target.endInBits() > CurrentFragment->endInBits())
30806c3fb27SDimitry Andric     return Skip;
30906c3fb27SDimitry Andric 
31006c3fb27SDimitry Andric   // Target fits within the current fragment, return it.
31106c3fb27SDimitry Andric   return UseFrag;
31206c3fb27SDimitry Andric }
31306c3fb27SDimitry Andric 
31406c3fb27SDimitry Andric static DebugVariable getAggregateVariable(DbgVariableIntrinsic *DVI) {
31506c3fb27SDimitry Andric   return DebugVariable(DVI->getVariable(), std::nullopt,
31606c3fb27SDimitry Andric                        DVI->getDebugLoc().getInlinedAt());
31706c3fb27SDimitry Andric }
318*0fca6ea1SDimitry Andric static DebugVariable getAggregateVariable(DbgVariableRecord *DVR) {
319*0fca6ea1SDimitry Andric   return DebugVariable(DVR->getVariable(), std::nullopt,
320*0fca6ea1SDimitry Andric                        DVR->getDebugLoc().getInlinedAt());
3217a6dacacSDimitry Andric }
3227a6dacacSDimitry Andric 
323*0fca6ea1SDimitry Andric /// Helpers for handling new and old debug info modes in migrateDebugInfo.
324*0fca6ea1SDimitry Andric /// These overloads unwrap a DbgInstPtr {Instruction* | DbgRecord*} union based
325*0fca6ea1SDimitry Andric /// on the \p Unused parameter type.
326*0fca6ea1SDimitry Andric DbgVariableRecord *UnwrapDbgInstPtr(DbgInstPtr P, DbgVariableRecord *Unused) {
327*0fca6ea1SDimitry Andric   (void)Unused;
328*0fca6ea1SDimitry Andric   return static_cast<DbgVariableRecord *>(cast<DbgRecord *>(P));
3297a6dacacSDimitry Andric }
330*0fca6ea1SDimitry Andric DbgAssignIntrinsic *UnwrapDbgInstPtr(DbgInstPtr P, DbgAssignIntrinsic *Unused) {
331*0fca6ea1SDimitry Andric   (void)Unused;
332*0fca6ea1SDimitry Andric   return static_cast<DbgAssignIntrinsic *>(cast<Instruction *>(P));
3337a6dacacSDimitry Andric }
33406c3fb27SDimitry Andric 
335bdd1243dSDimitry Andric /// Find linked dbg.assign and generate a new one with the correct
336bdd1243dSDimitry Andric /// FragmentInfo. Link Inst to the new dbg.assign.  If Value is nullptr the
337bdd1243dSDimitry Andric /// value component is copied from the old dbg.assign to the new.
338bdd1243dSDimitry Andric /// \param OldAlloca             Alloca for the variable before splitting.
33906c3fb27SDimitry Andric /// \param IsSplit               True if the store (not necessarily alloca)
34006c3fb27SDimitry Andric ///                              is being split.
34106c3fb27SDimitry Andric /// \param OldAllocaOffsetInBits Offset of the slice taken from OldAlloca.
342bdd1243dSDimitry Andric /// \param SliceSizeInBits       New number of bits being written to.
343bdd1243dSDimitry Andric /// \param OldInst               Instruction that is being split.
344bdd1243dSDimitry Andric /// \param Inst                  New instruction performing this part of the
345bdd1243dSDimitry Andric ///                              split store.
346bdd1243dSDimitry Andric /// \param Dest                  Store destination.
347bdd1243dSDimitry Andric /// \param Value                 Stored value.
348bdd1243dSDimitry Andric /// \param DL                    Datalayout.
34906c3fb27SDimitry Andric static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
35006c3fb27SDimitry Andric                              uint64_t OldAllocaOffsetInBits,
351bdd1243dSDimitry Andric                              uint64_t SliceSizeInBits, Instruction *OldInst,
352bdd1243dSDimitry Andric                              Instruction *Inst, Value *Dest, Value *Value,
353bdd1243dSDimitry Andric                              const DataLayout &DL) {
354bdd1243dSDimitry Andric   auto MarkerRange = at::getAssignmentMarkers(OldInst);
355*0fca6ea1SDimitry Andric   auto DVRAssignMarkerRange = at::getDVRAssignmentMarkers(OldInst);
356bdd1243dSDimitry Andric   // Nothing to do if OldInst has no linked dbg.assign intrinsics.
357*0fca6ea1SDimitry Andric   if (MarkerRange.empty() && DVRAssignMarkerRange.empty())
358bdd1243dSDimitry Andric     return;
359bdd1243dSDimitry Andric 
360bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "  migrateDebugInfo\n");
361bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    OldAlloca: " << *OldAlloca << "\n");
36206c3fb27SDimitry Andric   LLVM_DEBUG(dbgs() << "    IsSplit: " << IsSplit << "\n");
36306c3fb27SDimitry Andric   LLVM_DEBUG(dbgs() << "    OldAllocaOffsetInBits: " << OldAllocaOffsetInBits
36406c3fb27SDimitry Andric                     << "\n");
365bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    SliceSizeInBits: " << SliceSizeInBits << "\n");
366bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    OldInst: " << *OldInst << "\n");
367bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    Inst: " << *Inst << "\n");
368bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    Dest: " << *Dest << "\n");
369bdd1243dSDimitry Andric   if (Value)
370bdd1243dSDimitry Andric     LLVM_DEBUG(dbgs() << "    Value: " << *Value << "\n");
371bdd1243dSDimitry Andric 
37206c3fb27SDimitry Andric   /// Map of aggregate variables to their fragment associated with OldAlloca.
37306c3fb27SDimitry Andric   DenseMap<DebugVariable, std::optional<DIExpression::FragmentInfo>>
37406c3fb27SDimitry Andric       BaseFragments;
37506c3fb27SDimitry Andric   for (auto *DAI : at::getAssignmentMarkers(OldAlloca))
37606c3fb27SDimitry Andric     BaseFragments[getAggregateVariable(DAI)] =
37706c3fb27SDimitry Andric         DAI->getExpression()->getFragmentInfo();
378*0fca6ea1SDimitry Andric   for (auto *DVR : at::getDVRAssignmentMarkers(OldAlloca))
379*0fca6ea1SDimitry Andric     BaseFragments[getAggregateVariable(DVR)] =
380*0fca6ea1SDimitry Andric         DVR->getExpression()->getFragmentInfo();
38106c3fb27SDimitry Andric 
382bdd1243dSDimitry Andric   // The new inst needs a DIAssignID unique metadata tag (if OldInst has
383bdd1243dSDimitry Andric   // one). It shouldn't already have one: assert this assumption.
384bdd1243dSDimitry Andric   assert(!Inst->getMetadata(LLVMContext::MD_DIAssignID));
385bdd1243dSDimitry Andric   DIAssignID *NewID = nullptr;
386bdd1243dSDimitry Andric   auto &Ctx = Inst->getContext();
387bdd1243dSDimitry Andric   DIBuilder DIB(*OldInst->getModule(), /*AllowUnresolved*/ false);
388bdd1243dSDimitry Andric   assert(OldAlloca->isStaticAlloca());
389bdd1243dSDimitry Andric 
390*0fca6ea1SDimitry Andric   auto MigrateDbgAssign = [&](auto *DbgAssign) {
391bdd1243dSDimitry Andric     LLVM_DEBUG(dbgs() << "      existing dbg.assign is: " << *DbgAssign
392bdd1243dSDimitry Andric                       << "\n");
393bdd1243dSDimitry Andric     auto *Expr = DbgAssign->getExpression();
39406c3fb27SDimitry Andric     bool SetKillLocation = false;
395bdd1243dSDimitry Andric 
39606c3fb27SDimitry Andric     if (IsSplit) {
39706c3fb27SDimitry Andric       std::optional<DIExpression::FragmentInfo> BaseFragment;
39806c3fb27SDimitry Andric       {
39906c3fb27SDimitry Andric         auto R = BaseFragments.find(getAggregateVariable(DbgAssign));
40006c3fb27SDimitry Andric         if (R == BaseFragments.end())
4017a6dacacSDimitry Andric           return;
40206c3fb27SDimitry Andric         BaseFragment = R->second;
40306c3fb27SDimitry Andric       }
40406c3fb27SDimitry Andric       std::optional<DIExpression::FragmentInfo> CurrentFragment =
40506c3fb27SDimitry Andric           Expr->getFragmentInfo();
40606c3fb27SDimitry Andric       DIExpression::FragmentInfo NewFragment;
40706c3fb27SDimitry Andric       FragCalcResult Result = calculateFragment(
40806c3fb27SDimitry Andric           DbgAssign->getVariable(), OldAllocaOffsetInBits, SliceSizeInBits,
40906c3fb27SDimitry Andric           BaseFragment, CurrentFragment, NewFragment);
410bdd1243dSDimitry Andric 
41106c3fb27SDimitry Andric       if (Result == Skip)
4127a6dacacSDimitry Andric         return;
41306c3fb27SDimitry Andric       if (Result == UseFrag && !(NewFragment == CurrentFragment)) {
41406c3fb27SDimitry Andric         if (CurrentFragment) {
41506c3fb27SDimitry Andric           // Rewrite NewFragment to be relative to the existing one (this is
41606c3fb27SDimitry Andric           // what createFragmentExpression wants).  CalculateFragment has
41706c3fb27SDimitry Andric           // already resolved the size for us. FIXME: Should it return the
41806c3fb27SDimitry Andric           // relative fragment too?
41906c3fb27SDimitry Andric           NewFragment.OffsetInBits -= CurrentFragment->OffsetInBits;
42006c3fb27SDimitry Andric         }
42106c3fb27SDimitry Andric         // Add the new fragment info to the existing expression if possible.
42206c3fb27SDimitry Andric         if (auto E = DIExpression::createFragmentExpression(
42306c3fb27SDimitry Andric                 Expr, NewFragment.OffsetInBits, NewFragment.SizeInBits)) {
424bdd1243dSDimitry Andric           Expr = *E;
42506c3fb27SDimitry Andric         } else {
42606c3fb27SDimitry Andric           // Otherwise, add the new fragment info to an empty expression and
42706c3fb27SDimitry Andric           // discard the value component of this dbg.assign as the value cannot
42806c3fb27SDimitry Andric           // be computed with the new fragment.
42906c3fb27SDimitry Andric           Expr = *DIExpression::createFragmentExpression(
43006c3fb27SDimitry Andric               DIExpression::get(Expr->getContext(), std::nullopt),
43106c3fb27SDimitry Andric               NewFragment.OffsetInBits, NewFragment.SizeInBits);
43206c3fb27SDimitry Andric           SetKillLocation = true;
43306c3fb27SDimitry Andric         }
43406c3fb27SDimitry Andric       }
435bdd1243dSDimitry Andric     }
436bdd1243dSDimitry Andric 
437bdd1243dSDimitry Andric     // If we haven't created a DIAssignID ID do that now and attach it to Inst.
438bdd1243dSDimitry Andric     if (!NewID) {
439bdd1243dSDimitry Andric       NewID = DIAssignID::getDistinct(Ctx);
440bdd1243dSDimitry Andric       Inst->setMetadata(LLVMContext::MD_DIAssignID, NewID);
441bdd1243dSDimitry Andric     }
442bdd1243dSDimitry Andric 
44306c3fb27SDimitry Andric     ::Value *NewValue = Value ? Value : DbgAssign->getValue();
444*0fca6ea1SDimitry Andric     auto *NewAssign = UnwrapDbgInstPtr(
445*0fca6ea1SDimitry Andric         DIB.insertDbgAssign(Inst, NewValue, DbgAssign->getVariable(), Expr,
446*0fca6ea1SDimitry Andric                             Dest,
4477a6dacacSDimitry Andric                             DIExpression::get(Expr->getContext(), std::nullopt),
448*0fca6ea1SDimitry Andric                             DbgAssign->getDebugLoc()),
449*0fca6ea1SDimitry Andric         DbgAssign);
450bdd1243dSDimitry Andric 
45106c3fb27SDimitry Andric     // If we've updated the value but the original dbg.assign has an arglist
45206c3fb27SDimitry Andric     // then kill it now - we can't use the requested new value.
45306c3fb27SDimitry Andric     // We can't replace the DIArgList with the new value as it'd leave
45406c3fb27SDimitry Andric     // the DIExpression in an invalid state (DW_OP_LLVM_arg operands without
45506c3fb27SDimitry Andric     // an arglist). And we can't keep the DIArgList in case the linked store
45606c3fb27SDimitry Andric     // is being split - in which case the DIArgList + expression may no longer
45706c3fb27SDimitry Andric     // be computing the correct value.
45806c3fb27SDimitry Andric     // This should be a very rare situation as it requires the value being
45906c3fb27SDimitry Andric     // stored to differ from the dbg.assign (i.e., the value has been
46006c3fb27SDimitry Andric     // represented differently in the debug intrinsic for some reason).
46106c3fb27SDimitry Andric     SetKillLocation |=
46206c3fb27SDimitry Andric         Value && (DbgAssign->hasArgList() ||
46306c3fb27SDimitry Andric                   !DbgAssign->getExpression()->isSingleLocationExpression());
46406c3fb27SDimitry Andric     if (SetKillLocation)
46506c3fb27SDimitry Andric       NewAssign->setKillLocation();
46606c3fb27SDimitry Andric 
467bdd1243dSDimitry Andric     // We could use more precision here at the cost of some additional (code)
468bdd1243dSDimitry Andric     // complexity - if the original dbg.assign was adjacent to its store, we
469bdd1243dSDimitry Andric     // could position this new dbg.assign adjacent to its store rather than the
470bdd1243dSDimitry Andric     // old dbg.assgn. That would result in interleaved dbg.assigns rather than
471bdd1243dSDimitry Andric     // what we get now:
472bdd1243dSDimitry Andric     //    split store !1
473bdd1243dSDimitry Andric     //    split store !2
474bdd1243dSDimitry Andric     //    dbg.assign !1
475bdd1243dSDimitry Andric     //    dbg.assign !2
476bdd1243dSDimitry Andric     // This (current behaviour) results results in debug assignments being
477bdd1243dSDimitry Andric     // noted as slightly offset (in code) from the store. In practice this
478bdd1243dSDimitry Andric     // should have little effect on the debugging experience due to the fact
479bdd1243dSDimitry Andric     // that all the split stores should get the same line number.
480bdd1243dSDimitry Andric     NewAssign->moveBefore(DbgAssign);
481bdd1243dSDimitry Andric 
482bdd1243dSDimitry Andric     NewAssign->setDebugLoc(DbgAssign->getDebugLoc());
4837a6dacacSDimitry Andric     LLVM_DEBUG(dbgs() << "Created new assign: " << *NewAssign << "\n");
4847a6dacacSDimitry Andric   };
4857a6dacacSDimitry Andric 
4867a6dacacSDimitry Andric   for_each(MarkerRange, MigrateDbgAssign);
487*0fca6ea1SDimitry Andric   for_each(DVRAssignMarkerRange, MigrateDbgAssign);
488bdd1243dSDimitry Andric }
4890b57cec5SDimitry Andric 
4905f757f3fSDimitry Andric namespace {
4915f757f3fSDimitry Andric 
4920b57cec5SDimitry Andric /// A custom IRBuilder inserter which prefixes all names, but only in
4930b57cec5SDimitry Andric /// Assert builds.
4945ffd83dbSDimitry Andric class IRBuilderPrefixedInserter final : public IRBuilderDefaultInserter {
4950b57cec5SDimitry Andric   std::string Prefix;
4960b57cec5SDimitry Andric 
497349cc55cSDimitry Andric   Twine getNameWithPrefix(const Twine &Name) const {
4980b57cec5SDimitry Andric     return Name.isTriviallyEmpty() ? Name : Prefix + Name;
4990b57cec5SDimitry Andric   }
5000b57cec5SDimitry Andric 
5010b57cec5SDimitry Andric public:
5020b57cec5SDimitry Andric   void SetNamePrefix(const Twine &P) { Prefix = P.str(); }
5030b57cec5SDimitry Andric 
504*0fca6ea1SDimitry Andric   void InsertHelper(Instruction *I, const Twine &Name,
5055ffd83dbSDimitry Andric                     BasicBlock::iterator InsertPt) const override {
506*0fca6ea1SDimitry Andric     IRBuilderDefaultInserter::InsertHelper(I, getNameWithPrefix(Name),
5070b57cec5SDimitry Andric                                            InsertPt);
5080b57cec5SDimitry Andric   }
5090b57cec5SDimitry Andric };
5100b57cec5SDimitry Andric 
5110b57cec5SDimitry Andric /// Provide a type for IRBuilder that drops names in release builds.
5120b57cec5SDimitry Andric using IRBuilderTy = IRBuilder<ConstantFolder, IRBuilderPrefixedInserter>;
5130b57cec5SDimitry Andric 
5140b57cec5SDimitry Andric /// A used slice of an alloca.
5150b57cec5SDimitry Andric ///
5160b57cec5SDimitry Andric /// This structure represents a slice of an alloca used by some instruction. It
5170b57cec5SDimitry Andric /// stores both the begin and end offsets of this use, a pointer to the use
5180b57cec5SDimitry Andric /// itself, and a flag indicating whether we can classify the use as splittable
5190b57cec5SDimitry Andric /// or not when forming partitions of the alloca.
5200b57cec5SDimitry Andric class Slice {
5210b57cec5SDimitry Andric   /// The beginning offset of the range.
5220b57cec5SDimitry Andric   uint64_t BeginOffset = 0;
5230b57cec5SDimitry Andric 
5240b57cec5SDimitry Andric   /// The ending offset, not included in the range.
5250b57cec5SDimitry Andric   uint64_t EndOffset = 0;
5260b57cec5SDimitry Andric 
5270b57cec5SDimitry Andric   /// Storage for both the use of this slice and whether it can be
5280b57cec5SDimitry Andric   /// split.
5290b57cec5SDimitry Andric   PointerIntPair<Use *, 1, bool> UseAndIsSplittable;
5300b57cec5SDimitry Andric 
5310b57cec5SDimitry Andric public:
5320b57cec5SDimitry Andric   Slice() = default;
5330b57cec5SDimitry Andric 
5340b57cec5SDimitry Andric   Slice(uint64_t BeginOffset, uint64_t EndOffset, Use *U, bool IsSplittable)
5350b57cec5SDimitry Andric       : BeginOffset(BeginOffset), EndOffset(EndOffset),
5360b57cec5SDimitry Andric         UseAndIsSplittable(U, IsSplittable) {}
5370b57cec5SDimitry Andric 
5380b57cec5SDimitry Andric   uint64_t beginOffset() const { return BeginOffset; }
5390b57cec5SDimitry Andric   uint64_t endOffset() const { return EndOffset; }
5400b57cec5SDimitry Andric 
5410b57cec5SDimitry Andric   bool isSplittable() const { return UseAndIsSplittable.getInt(); }
5420b57cec5SDimitry Andric   void makeUnsplittable() { UseAndIsSplittable.setInt(false); }
5430b57cec5SDimitry Andric 
5440b57cec5SDimitry Andric   Use *getUse() const { return UseAndIsSplittable.getPointer(); }
5450b57cec5SDimitry Andric 
5460b57cec5SDimitry Andric   bool isDead() const { return getUse() == nullptr; }
5470b57cec5SDimitry Andric   void kill() { UseAndIsSplittable.setPointer(nullptr); }
5480b57cec5SDimitry Andric 
5490b57cec5SDimitry Andric   /// Support for ordering ranges.
5500b57cec5SDimitry Andric   ///
5510b57cec5SDimitry Andric   /// This provides an ordering over ranges such that start offsets are
5520b57cec5SDimitry Andric   /// always increasing, and within equal start offsets, the end offsets are
5530b57cec5SDimitry Andric   /// decreasing. Thus the spanning range comes first in a cluster with the
5540b57cec5SDimitry Andric   /// same start position.
5550b57cec5SDimitry Andric   bool operator<(const Slice &RHS) const {
5560b57cec5SDimitry Andric     if (beginOffset() < RHS.beginOffset())
5570b57cec5SDimitry Andric       return true;
5580b57cec5SDimitry Andric     if (beginOffset() > RHS.beginOffset())
5590b57cec5SDimitry Andric       return false;
5600b57cec5SDimitry Andric     if (isSplittable() != RHS.isSplittable())
5610b57cec5SDimitry Andric       return !isSplittable();
5620b57cec5SDimitry Andric     if (endOffset() > RHS.endOffset())
5630b57cec5SDimitry Andric       return true;
5640b57cec5SDimitry Andric     return false;
5650b57cec5SDimitry Andric   }
5660b57cec5SDimitry Andric 
5670b57cec5SDimitry Andric   /// Support comparison with a single offset to allow binary searches.
5680b57cec5SDimitry Andric   friend LLVM_ATTRIBUTE_UNUSED bool operator<(const Slice &LHS,
5690b57cec5SDimitry Andric                                               uint64_t RHSOffset) {
5700b57cec5SDimitry Andric     return LHS.beginOffset() < RHSOffset;
5710b57cec5SDimitry Andric   }
5720b57cec5SDimitry Andric   friend LLVM_ATTRIBUTE_UNUSED bool operator<(uint64_t LHSOffset,
5730b57cec5SDimitry Andric                                               const Slice &RHS) {
5740b57cec5SDimitry Andric     return LHSOffset < RHS.beginOffset();
5750b57cec5SDimitry Andric   }
5760b57cec5SDimitry Andric 
5770b57cec5SDimitry Andric   bool operator==(const Slice &RHS) const {
5780b57cec5SDimitry Andric     return isSplittable() == RHS.isSplittable() &&
5790b57cec5SDimitry Andric            beginOffset() == RHS.beginOffset() && endOffset() == RHS.endOffset();
5800b57cec5SDimitry Andric   }
5810b57cec5SDimitry Andric   bool operator!=(const Slice &RHS) const { return !operator==(RHS); }
5820b57cec5SDimitry Andric };
5830b57cec5SDimitry Andric 
5840b57cec5SDimitry Andric /// Representation of the alloca slices.
5850b57cec5SDimitry Andric ///
5860b57cec5SDimitry Andric /// This class represents the slices of an alloca which are formed by its
5870b57cec5SDimitry Andric /// various uses. If a pointer escapes, we can't fully build a representation
5880b57cec5SDimitry Andric /// for the slices used and we reflect that in this structure. The uses are
5890b57cec5SDimitry Andric /// stored, sorted by increasing beginning offset and with unsplittable slices
5900b57cec5SDimitry Andric /// starting at a particular offset before splittable slices.
5915f757f3fSDimitry Andric class AllocaSlices {
5920b57cec5SDimitry Andric public:
5930b57cec5SDimitry Andric   /// Construct the slices of a particular alloca.
5940b57cec5SDimitry Andric   AllocaSlices(const DataLayout &DL, AllocaInst &AI);
5950b57cec5SDimitry Andric 
5960b57cec5SDimitry Andric   /// Test whether a pointer to the allocation escapes our analysis.
5970b57cec5SDimitry Andric   ///
5980b57cec5SDimitry Andric   /// If this is true, the slices are never fully built and should be
5990b57cec5SDimitry Andric   /// ignored.
6000b57cec5SDimitry Andric   bool isEscaped() const { return PointerEscapingInstr; }
6010b57cec5SDimitry Andric 
6020b57cec5SDimitry Andric   /// Support for iterating over the slices.
6030b57cec5SDimitry Andric   /// @{
6040b57cec5SDimitry Andric   using iterator = SmallVectorImpl<Slice>::iterator;
6050b57cec5SDimitry Andric   using range = iterator_range<iterator>;
6060b57cec5SDimitry Andric 
6070b57cec5SDimitry Andric   iterator begin() { return Slices.begin(); }
6080b57cec5SDimitry Andric   iterator end() { return Slices.end(); }
6090b57cec5SDimitry Andric 
6100b57cec5SDimitry Andric   using const_iterator = SmallVectorImpl<Slice>::const_iterator;
6110b57cec5SDimitry Andric   using const_range = iterator_range<const_iterator>;
6120b57cec5SDimitry Andric 
6130b57cec5SDimitry Andric   const_iterator begin() const { return Slices.begin(); }
6140b57cec5SDimitry Andric   const_iterator end() const { return Slices.end(); }
6150b57cec5SDimitry Andric   /// @}
6160b57cec5SDimitry Andric 
6170b57cec5SDimitry Andric   /// Erase a range of slices.
6180b57cec5SDimitry Andric   void erase(iterator Start, iterator Stop) { Slices.erase(Start, Stop); }
6190b57cec5SDimitry Andric 
6200b57cec5SDimitry Andric   /// Insert new slices for this alloca.
6210b57cec5SDimitry Andric   ///
6220b57cec5SDimitry Andric   /// This moves the slices into the alloca's slices collection, and re-sorts
6230b57cec5SDimitry Andric   /// everything so that the usual ordering properties of the alloca's slices
6240b57cec5SDimitry Andric   /// hold.
6250b57cec5SDimitry Andric   void insert(ArrayRef<Slice> NewSlices) {
6260b57cec5SDimitry Andric     int OldSize = Slices.size();
6270b57cec5SDimitry Andric     Slices.append(NewSlices.begin(), NewSlices.end());
6280b57cec5SDimitry Andric     auto SliceI = Slices.begin() + OldSize;
629*0fca6ea1SDimitry Andric     std::stable_sort(SliceI, Slices.end());
6300b57cec5SDimitry Andric     std::inplace_merge(Slices.begin(), SliceI, Slices.end());
6310b57cec5SDimitry Andric   }
6320b57cec5SDimitry Andric 
6330b57cec5SDimitry Andric   // Forward declare the iterator and range accessor for walking the
6340b57cec5SDimitry Andric   // partitions.
6350b57cec5SDimitry Andric   class partition_iterator;
6360b57cec5SDimitry Andric   iterator_range<partition_iterator> partitions();
6370b57cec5SDimitry Andric 
6380b57cec5SDimitry Andric   /// Access the dead users for this alloca.
6390b57cec5SDimitry Andric   ArrayRef<Instruction *> getDeadUsers() const { return DeadUsers; }
6400b57cec5SDimitry Andric 
641e8d8bef9SDimitry Andric   /// Access Uses that should be dropped if the alloca is promotable.
642e8d8bef9SDimitry Andric   ArrayRef<Use *> getDeadUsesIfPromotable() const {
643e8d8bef9SDimitry Andric     return DeadUseIfPromotable;
644e8d8bef9SDimitry Andric   }
645e8d8bef9SDimitry Andric 
6460b57cec5SDimitry Andric   /// Access the dead operands referring to this alloca.
6470b57cec5SDimitry Andric   ///
6480b57cec5SDimitry Andric   /// These are operands which have cannot actually be used to refer to the
6490b57cec5SDimitry Andric   /// alloca as they are outside its range and the user doesn't correct for
6500b57cec5SDimitry Andric   /// that. These mostly consist of PHI node inputs and the like which we just
6510b57cec5SDimitry Andric   /// need to replace with undef.
6520b57cec5SDimitry Andric   ArrayRef<Use *> getDeadOperands() const { return DeadOperands; }
6530b57cec5SDimitry Andric 
6540b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
6550b57cec5SDimitry Andric   void print(raw_ostream &OS, const_iterator I, StringRef Indent = "  ") const;
6560b57cec5SDimitry Andric   void printSlice(raw_ostream &OS, const_iterator I,
6570b57cec5SDimitry Andric                   StringRef Indent = "  ") const;
6580b57cec5SDimitry Andric   void printUse(raw_ostream &OS, const_iterator I,
6590b57cec5SDimitry Andric                 StringRef Indent = "  ") const;
6600b57cec5SDimitry Andric   void print(raw_ostream &OS) const;
6610b57cec5SDimitry Andric   void dump(const_iterator I) const;
6620b57cec5SDimitry Andric   void dump() const;
6630b57cec5SDimitry Andric #endif
6640b57cec5SDimitry Andric 
6650b57cec5SDimitry Andric private:
6660b57cec5SDimitry Andric   template <typename DerivedT, typename RetT = void> class BuilderBase;
6670b57cec5SDimitry Andric   class SliceBuilder;
6680b57cec5SDimitry Andric 
6690b57cec5SDimitry Andric   friend class AllocaSlices::SliceBuilder;
6700b57cec5SDimitry Andric 
6710b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
6720b57cec5SDimitry Andric   /// Handle to alloca instruction to simplify method interfaces.
6730b57cec5SDimitry Andric   AllocaInst &AI;
6740b57cec5SDimitry Andric #endif
6750b57cec5SDimitry Andric 
6760b57cec5SDimitry Andric   /// The instruction responsible for this alloca not having a known set
6770b57cec5SDimitry Andric   /// of slices.
6780b57cec5SDimitry Andric   ///
6790b57cec5SDimitry Andric   /// When an instruction (potentially) escapes the pointer to the alloca, we
6800b57cec5SDimitry Andric   /// store a pointer to that here and abort trying to form slices of the
6810b57cec5SDimitry Andric   /// alloca. This will be null if the alloca slices are analyzed successfully.
6820b57cec5SDimitry Andric   Instruction *PointerEscapingInstr;
6830b57cec5SDimitry Andric 
6840b57cec5SDimitry Andric   /// The slices of the alloca.
6850b57cec5SDimitry Andric   ///
6860b57cec5SDimitry Andric   /// We store a vector of the slices formed by uses of the alloca here. This
6870b57cec5SDimitry Andric   /// vector is sorted by increasing begin offset, and then the unsplittable
6880b57cec5SDimitry Andric   /// slices before the splittable ones. See the Slice inner class for more
6890b57cec5SDimitry Andric   /// details.
6900b57cec5SDimitry Andric   SmallVector<Slice, 8> Slices;
6910b57cec5SDimitry Andric 
6920b57cec5SDimitry Andric   /// Instructions which will become dead if we rewrite the alloca.
6930b57cec5SDimitry Andric   ///
6940b57cec5SDimitry Andric   /// Note that these are not separated by slice. This is because we expect an
6950b57cec5SDimitry Andric   /// alloca to be completely rewritten or not rewritten at all. If rewritten,
69604eeddc0SDimitry Andric   /// all these instructions can simply be removed and replaced with poison as
6970b57cec5SDimitry Andric   /// they come from outside of the allocated space.
6980b57cec5SDimitry Andric   SmallVector<Instruction *, 8> DeadUsers;
6990b57cec5SDimitry Andric 
700e8d8bef9SDimitry Andric   /// Uses which will become dead if can promote the alloca.
701e8d8bef9SDimitry Andric   SmallVector<Use *, 8> DeadUseIfPromotable;
702e8d8bef9SDimitry Andric 
7030b57cec5SDimitry Andric   /// Operands which will become dead if we rewrite the alloca.
7040b57cec5SDimitry Andric   ///
7050b57cec5SDimitry Andric   /// These are operands that in their particular use can be replaced with
70604eeddc0SDimitry Andric   /// poison when we rewrite the alloca. These show up in out-of-bounds inputs
7070b57cec5SDimitry Andric   /// to PHI nodes and the like. They aren't entirely dead (there might be
7080b57cec5SDimitry Andric   /// a GEP back into the bounds using it elsewhere) and nor is the PHI, but we
70904eeddc0SDimitry Andric   /// want to swap this particular input for poison to simplify the use lists of
7100b57cec5SDimitry Andric   /// the alloca.
7110b57cec5SDimitry Andric   SmallVector<Use *, 8> DeadOperands;
7120b57cec5SDimitry Andric };
7130b57cec5SDimitry Andric 
7140b57cec5SDimitry Andric /// A partition of the slices.
7150b57cec5SDimitry Andric ///
7160b57cec5SDimitry Andric /// An ephemeral representation for a range of slices which can be viewed as
7170b57cec5SDimitry Andric /// a partition of the alloca. This range represents a span of the alloca's
7180b57cec5SDimitry Andric /// memory which cannot be split, and provides access to all of the slices
7190b57cec5SDimitry Andric /// overlapping some part of the partition.
7200b57cec5SDimitry Andric ///
7210b57cec5SDimitry Andric /// Objects of this type are produced by traversing the alloca's slices, but
7220b57cec5SDimitry Andric /// are only ephemeral and not persistent.
7235f757f3fSDimitry Andric class Partition {
7240b57cec5SDimitry Andric private:
7250b57cec5SDimitry Andric   friend class AllocaSlices;
7260b57cec5SDimitry Andric   friend class AllocaSlices::partition_iterator;
7270b57cec5SDimitry Andric 
7280b57cec5SDimitry Andric   using iterator = AllocaSlices::iterator;
7290b57cec5SDimitry Andric 
7300b57cec5SDimitry Andric   /// The beginning and ending offsets of the alloca for this
7310b57cec5SDimitry Andric   /// partition.
732480093f4SDimitry Andric   uint64_t BeginOffset = 0, EndOffset = 0;
7330b57cec5SDimitry Andric 
7340b57cec5SDimitry Andric   /// The start and end iterators of this partition.
7350b57cec5SDimitry Andric   iterator SI, SJ;
7360b57cec5SDimitry Andric 
7370b57cec5SDimitry Andric   /// A collection of split slice tails overlapping the partition.
7380b57cec5SDimitry Andric   SmallVector<Slice *, 4> SplitTails;
7390b57cec5SDimitry Andric 
7400b57cec5SDimitry Andric   /// Raw constructor builds an empty partition starting and ending at
7410b57cec5SDimitry Andric   /// the given iterator.
7420b57cec5SDimitry Andric   Partition(iterator SI) : SI(SI), SJ(SI) {}
7430b57cec5SDimitry Andric 
7440b57cec5SDimitry Andric public:
7450b57cec5SDimitry Andric   /// The start offset of this partition.
7460b57cec5SDimitry Andric   ///
7470b57cec5SDimitry Andric   /// All of the contained slices start at or after this offset.
7480b57cec5SDimitry Andric   uint64_t beginOffset() const { return BeginOffset; }
7490b57cec5SDimitry Andric 
7500b57cec5SDimitry Andric   /// The end offset of this partition.
7510b57cec5SDimitry Andric   ///
7520b57cec5SDimitry Andric   /// All of the contained slices end at or before this offset.
7530b57cec5SDimitry Andric   uint64_t endOffset() const { return EndOffset; }
7540b57cec5SDimitry Andric 
7550b57cec5SDimitry Andric   /// The size of the partition.
7560b57cec5SDimitry Andric   ///
7570b57cec5SDimitry Andric   /// Note that this can never be zero.
7580b57cec5SDimitry Andric   uint64_t size() const {
7590b57cec5SDimitry Andric     assert(BeginOffset < EndOffset && "Partitions must span some bytes!");
7600b57cec5SDimitry Andric     return EndOffset - BeginOffset;
7610b57cec5SDimitry Andric   }
7620b57cec5SDimitry Andric 
7630b57cec5SDimitry Andric   /// Test whether this partition contains no slices, and merely spans
7640b57cec5SDimitry Andric   /// a region occupied by split slices.
7650b57cec5SDimitry Andric   bool empty() const { return SI == SJ; }
7660b57cec5SDimitry Andric 
7670b57cec5SDimitry Andric   /// \name Iterate slices that start within the partition.
7680b57cec5SDimitry Andric   /// These may be splittable or unsplittable. They have a begin offset >= the
7690b57cec5SDimitry Andric   /// partition begin offset.
7700b57cec5SDimitry Andric   /// @{
7710b57cec5SDimitry Andric   // FIXME: We should probably define a "concat_iterator" helper and use that
7720b57cec5SDimitry Andric   // to stitch together pointee_iterators over the split tails and the
7730b57cec5SDimitry Andric   // contiguous iterators of the partition. That would give a much nicer
7740b57cec5SDimitry Andric   // interface here. We could then additionally expose filtered iterators for
7750b57cec5SDimitry Andric   // split, unsplit, and unsplittable splices based on the usage patterns.
7760b57cec5SDimitry Andric   iterator begin() const { return SI; }
7770b57cec5SDimitry Andric   iterator end() const { return SJ; }
7780b57cec5SDimitry Andric   /// @}
7790b57cec5SDimitry Andric 
7800b57cec5SDimitry Andric   /// Get the sequence of split slice tails.
7810b57cec5SDimitry Andric   ///
7820b57cec5SDimitry Andric   /// These tails are of slices which start before this partition but are
7830b57cec5SDimitry Andric   /// split and overlap into the partition. We accumulate these while forming
7840b57cec5SDimitry Andric   /// partitions.
7850b57cec5SDimitry Andric   ArrayRef<Slice *> splitSliceTails() const { return SplitTails; }
7860b57cec5SDimitry Andric };
7870b57cec5SDimitry Andric 
7885f757f3fSDimitry Andric } // end anonymous namespace
7895f757f3fSDimitry Andric 
7900b57cec5SDimitry Andric /// An iterator over partitions of the alloca's slices.
7910b57cec5SDimitry Andric ///
7920b57cec5SDimitry Andric /// This iterator implements the core algorithm for partitioning the alloca's
7930b57cec5SDimitry Andric /// slices. It is a forward iterator as we don't support backtracking for
7940b57cec5SDimitry Andric /// efficiency reasons, and re-use a single storage area to maintain the
7950b57cec5SDimitry Andric /// current set of split slices.
7960b57cec5SDimitry Andric ///
7970b57cec5SDimitry Andric /// It is templated on the slice iterator type to use so that it can operate
7980b57cec5SDimitry Andric /// with either const or non-const slice iterators.
7990b57cec5SDimitry Andric class AllocaSlices::partition_iterator
8000b57cec5SDimitry Andric     : public iterator_facade_base<partition_iterator, std::forward_iterator_tag,
8010b57cec5SDimitry Andric                                   Partition> {
8020b57cec5SDimitry Andric   friend class AllocaSlices;
8030b57cec5SDimitry Andric 
8040b57cec5SDimitry Andric   /// Most of the state for walking the partitions is held in a class
8050b57cec5SDimitry Andric   /// with a nice interface for examining them.
8060b57cec5SDimitry Andric   Partition P;
8070b57cec5SDimitry Andric 
8080b57cec5SDimitry Andric   /// We need to keep the end of the slices to know when to stop.
8090b57cec5SDimitry Andric   AllocaSlices::iterator SE;
8100b57cec5SDimitry Andric 
8110b57cec5SDimitry Andric   /// We also need to keep track of the maximum split end offset seen.
8120b57cec5SDimitry Andric   /// FIXME: Do we really?
8130b57cec5SDimitry Andric   uint64_t MaxSplitSliceEndOffset = 0;
8140b57cec5SDimitry Andric 
8150b57cec5SDimitry Andric   /// Sets the partition to be empty at given iterator, and sets the
8160b57cec5SDimitry Andric   /// end iterator.
8170b57cec5SDimitry Andric   partition_iterator(AllocaSlices::iterator SI, AllocaSlices::iterator SE)
8180b57cec5SDimitry Andric       : P(SI), SE(SE) {
8190b57cec5SDimitry Andric     // If not already at the end, advance our state to form the initial
8200b57cec5SDimitry Andric     // partition.
8210b57cec5SDimitry Andric     if (SI != SE)
8220b57cec5SDimitry Andric       advance();
8230b57cec5SDimitry Andric   }
8240b57cec5SDimitry Andric 
8250b57cec5SDimitry Andric   /// Advance the iterator to the next partition.
8260b57cec5SDimitry Andric   ///
8270b57cec5SDimitry Andric   /// Requires that the iterator not be at the end of the slices.
8280b57cec5SDimitry Andric   void advance() {
8290b57cec5SDimitry Andric     assert((P.SI != SE || !P.SplitTails.empty()) &&
8300b57cec5SDimitry Andric            "Cannot advance past the end of the slices!");
8310b57cec5SDimitry Andric 
8320b57cec5SDimitry Andric     // Clear out any split uses which have ended.
8330b57cec5SDimitry Andric     if (!P.SplitTails.empty()) {
8340b57cec5SDimitry Andric       if (P.EndOffset >= MaxSplitSliceEndOffset) {
8350b57cec5SDimitry Andric         // If we've finished all splits, this is easy.
8360b57cec5SDimitry Andric         P.SplitTails.clear();
8370b57cec5SDimitry Andric         MaxSplitSliceEndOffset = 0;
8380b57cec5SDimitry Andric       } else {
8390b57cec5SDimitry Andric         // Remove the uses which have ended in the prior partition. This
8400b57cec5SDimitry Andric         // cannot change the max split slice end because we just checked that
8410b57cec5SDimitry Andric         // the prior partition ended prior to that max.
842e8d8bef9SDimitry Andric         llvm::erase_if(P.SplitTails,
843e8d8bef9SDimitry Andric                        [&](Slice *S) { return S->endOffset() <= P.EndOffset; });
8440b57cec5SDimitry Andric         assert(llvm::any_of(P.SplitTails,
8450b57cec5SDimitry Andric                             [&](Slice *S) {
8460b57cec5SDimitry Andric                               return S->endOffset() == MaxSplitSliceEndOffset;
8470b57cec5SDimitry Andric                             }) &&
8480b57cec5SDimitry Andric                "Could not find the current max split slice offset!");
8490b57cec5SDimitry Andric         assert(llvm::all_of(P.SplitTails,
8500b57cec5SDimitry Andric                             [&](Slice *S) {
8510b57cec5SDimitry Andric                               return S->endOffset() <= MaxSplitSliceEndOffset;
8520b57cec5SDimitry Andric                             }) &&
8530b57cec5SDimitry Andric                "Max split slice end offset is not actually the max!");
8540b57cec5SDimitry Andric       }
8550b57cec5SDimitry Andric     }
8560b57cec5SDimitry Andric 
8570b57cec5SDimitry Andric     // If P.SI is already at the end, then we've cleared the split tail and
8580b57cec5SDimitry Andric     // now have an end iterator.
8590b57cec5SDimitry Andric     if (P.SI == SE) {
8600b57cec5SDimitry Andric       assert(P.SplitTails.empty() && "Failed to clear the split slices!");
8610b57cec5SDimitry Andric       return;
8620b57cec5SDimitry Andric     }
8630b57cec5SDimitry Andric 
8640b57cec5SDimitry Andric     // If we had a non-empty partition previously, set up the state for
8650b57cec5SDimitry Andric     // subsequent partitions.
8660b57cec5SDimitry Andric     if (P.SI != P.SJ) {
8670b57cec5SDimitry Andric       // Accumulate all the splittable slices which started in the old
8680b57cec5SDimitry Andric       // partition into the split list.
8690b57cec5SDimitry Andric       for (Slice &S : P)
8700b57cec5SDimitry Andric         if (S.isSplittable() && S.endOffset() > P.EndOffset) {
8710b57cec5SDimitry Andric           P.SplitTails.push_back(&S);
8720b57cec5SDimitry Andric           MaxSplitSliceEndOffset =
8730b57cec5SDimitry Andric               std::max(S.endOffset(), MaxSplitSliceEndOffset);
8740b57cec5SDimitry Andric         }
8750b57cec5SDimitry Andric 
8760b57cec5SDimitry Andric       // Start from the end of the previous partition.
8770b57cec5SDimitry Andric       P.SI = P.SJ;
8780b57cec5SDimitry Andric 
8790b57cec5SDimitry Andric       // If P.SI is now at the end, we at most have a tail of split slices.
8800b57cec5SDimitry Andric       if (P.SI == SE) {
8810b57cec5SDimitry Andric         P.BeginOffset = P.EndOffset;
8820b57cec5SDimitry Andric         P.EndOffset = MaxSplitSliceEndOffset;
8830b57cec5SDimitry Andric         return;
8840b57cec5SDimitry Andric       }
8850b57cec5SDimitry Andric 
8860b57cec5SDimitry Andric       // If the we have split slices and the next slice is after a gap and is
8870b57cec5SDimitry Andric       // not splittable immediately form an empty partition for the split
8880b57cec5SDimitry Andric       // slices up until the next slice begins.
8890b57cec5SDimitry Andric       if (!P.SplitTails.empty() && P.SI->beginOffset() != P.EndOffset &&
8900b57cec5SDimitry Andric           !P.SI->isSplittable()) {
8910b57cec5SDimitry Andric         P.BeginOffset = P.EndOffset;
8920b57cec5SDimitry Andric         P.EndOffset = P.SI->beginOffset();
8930b57cec5SDimitry Andric         return;
8940b57cec5SDimitry Andric       }
8950b57cec5SDimitry Andric     }
8960b57cec5SDimitry Andric 
8970b57cec5SDimitry Andric     // OK, we need to consume new slices. Set the end offset based on the
8980b57cec5SDimitry Andric     // current slice, and step SJ past it. The beginning offset of the
8990b57cec5SDimitry Andric     // partition is the beginning offset of the next slice unless we have
9000b57cec5SDimitry Andric     // pre-existing split slices that are continuing, in which case we begin
9010b57cec5SDimitry Andric     // at the prior end offset.
9020b57cec5SDimitry Andric     P.BeginOffset = P.SplitTails.empty() ? P.SI->beginOffset() : P.EndOffset;
9030b57cec5SDimitry Andric     P.EndOffset = P.SI->endOffset();
9040b57cec5SDimitry Andric     ++P.SJ;
9050b57cec5SDimitry Andric 
9060b57cec5SDimitry Andric     // There are two strategies to form a partition based on whether the
9070b57cec5SDimitry Andric     // partition starts with an unsplittable slice or a splittable slice.
9080b57cec5SDimitry Andric     if (!P.SI->isSplittable()) {
9090b57cec5SDimitry Andric       // When we're forming an unsplittable region, it must always start at
9100b57cec5SDimitry Andric       // the first slice and will extend through its end.
9110b57cec5SDimitry Andric       assert(P.BeginOffset == P.SI->beginOffset());
9120b57cec5SDimitry Andric 
9130b57cec5SDimitry Andric       // Form a partition including all of the overlapping slices with this
9140b57cec5SDimitry Andric       // unsplittable slice.
9150b57cec5SDimitry Andric       while (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset) {
9160b57cec5SDimitry Andric         if (!P.SJ->isSplittable())
9170b57cec5SDimitry Andric           P.EndOffset = std::max(P.EndOffset, P.SJ->endOffset());
9180b57cec5SDimitry Andric         ++P.SJ;
9190b57cec5SDimitry Andric       }
9200b57cec5SDimitry Andric 
9210b57cec5SDimitry Andric       // We have a partition across a set of overlapping unsplittable
9220b57cec5SDimitry Andric       // partitions.
9230b57cec5SDimitry Andric       return;
9240b57cec5SDimitry Andric     }
9250b57cec5SDimitry Andric 
9260b57cec5SDimitry Andric     // If we're starting with a splittable slice, then we need to form
9270b57cec5SDimitry Andric     // a synthetic partition spanning it and any other overlapping splittable
9280b57cec5SDimitry Andric     // splices.
9290b57cec5SDimitry Andric     assert(P.SI->isSplittable() && "Forming a splittable partition!");
9300b57cec5SDimitry Andric 
9310b57cec5SDimitry Andric     // Collect all of the overlapping splittable slices.
9320b57cec5SDimitry Andric     while (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset &&
9330b57cec5SDimitry Andric            P.SJ->isSplittable()) {
9340b57cec5SDimitry Andric       P.EndOffset = std::max(P.EndOffset, P.SJ->endOffset());
9350b57cec5SDimitry Andric       ++P.SJ;
9360b57cec5SDimitry Andric     }
9370b57cec5SDimitry Andric 
9380b57cec5SDimitry Andric     // Back upiP.EndOffset if we ended the span early when encountering an
9390b57cec5SDimitry Andric     // unsplittable slice. This synthesizes the early end offset of
9400b57cec5SDimitry Andric     // a partition spanning only splittable slices.
9410b57cec5SDimitry Andric     if (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset) {
9420b57cec5SDimitry Andric       assert(!P.SJ->isSplittable());
9430b57cec5SDimitry Andric       P.EndOffset = P.SJ->beginOffset();
9440b57cec5SDimitry Andric     }
9450b57cec5SDimitry Andric   }
9460b57cec5SDimitry Andric 
9470b57cec5SDimitry Andric public:
9480b57cec5SDimitry Andric   bool operator==(const partition_iterator &RHS) const {
9490b57cec5SDimitry Andric     assert(SE == RHS.SE &&
9500b57cec5SDimitry Andric            "End iterators don't match between compared partition iterators!");
9510b57cec5SDimitry Andric 
9520b57cec5SDimitry Andric     // The observed positions of partitions is marked by the P.SI iterator and
9530b57cec5SDimitry Andric     // the emptiness of the split slices. The latter is only relevant when
9540b57cec5SDimitry Andric     // P.SI == SE, as the end iterator will additionally have an empty split
9550b57cec5SDimitry Andric     // slices list, but the prior may have the same P.SI and a tail of split
9560b57cec5SDimitry Andric     // slices.
9570b57cec5SDimitry Andric     if (P.SI == RHS.P.SI && P.SplitTails.empty() == RHS.P.SplitTails.empty()) {
9580b57cec5SDimitry Andric       assert(P.SJ == RHS.P.SJ &&
9590b57cec5SDimitry Andric              "Same set of slices formed two different sized partitions!");
9600b57cec5SDimitry Andric       assert(P.SplitTails.size() == RHS.P.SplitTails.size() &&
9610b57cec5SDimitry Andric              "Same slice position with differently sized non-empty split "
9620b57cec5SDimitry Andric              "slice tails!");
9630b57cec5SDimitry Andric       return true;
9640b57cec5SDimitry Andric     }
9650b57cec5SDimitry Andric     return false;
9660b57cec5SDimitry Andric   }
9670b57cec5SDimitry Andric 
9680b57cec5SDimitry Andric   partition_iterator &operator++() {
9690b57cec5SDimitry Andric     advance();
9700b57cec5SDimitry Andric     return *this;
9710b57cec5SDimitry Andric   }
9720b57cec5SDimitry Andric 
9730b57cec5SDimitry Andric   Partition &operator*() { return P; }
9740b57cec5SDimitry Andric };
9750b57cec5SDimitry Andric 
9760b57cec5SDimitry Andric /// A forward range over the partitions of the alloca's slices.
9770b57cec5SDimitry Andric ///
9780b57cec5SDimitry Andric /// This accesses an iterator range over the partitions of the alloca's
9790b57cec5SDimitry Andric /// slices. It computes these partitions on the fly based on the overlapping
9800b57cec5SDimitry Andric /// offsets of the slices and the ability to split them. It will visit "empty"
9810b57cec5SDimitry Andric /// partitions to cover regions of the alloca only accessed via split
9820b57cec5SDimitry Andric /// slices.
9830b57cec5SDimitry Andric iterator_range<AllocaSlices::partition_iterator> AllocaSlices::partitions() {
9840b57cec5SDimitry Andric   return make_range(partition_iterator(begin(), end()),
9850b57cec5SDimitry Andric                     partition_iterator(end(), end()));
9860b57cec5SDimitry Andric }
9870b57cec5SDimitry Andric 
9880b57cec5SDimitry Andric static Value *foldSelectInst(SelectInst &SI) {
9890b57cec5SDimitry Andric   // If the condition being selected on is a constant or the same value is
9900b57cec5SDimitry Andric   // being selected between, fold the select. Yes this does (rarely) happen
9910b57cec5SDimitry Andric   // early on.
9920b57cec5SDimitry Andric   if (ConstantInt *CI = dyn_cast<ConstantInt>(SI.getCondition()))
9930b57cec5SDimitry Andric     return SI.getOperand(1 + CI->isZero());
9940b57cec5SDimitry Andric   if (SI.getOperand(1) == SI.getOperand(2))
9950b57cec5SDimitry Andric     return SI.getOperand(1);
9960b57cec5SDimitry Andric 
9970b57cec5SDimitry Andric   return nullptr;
9980b57cec5SDimitry Andric }
9990b57cec5SDimitry Andric 
10000b57cec5SDimitry Andric /// A helper that folds a PHI node or a select.
10010b57cec5SDimitry Andric static Value *foldPHINodeOrSelectInst(Instruction &I) {
10020b57cec5SDimitry Andric   if (PHINode *PN = dyn_cast<PHINode>(&I)) {
10030b57cec5SDimitry Andric     // If PN merges together the same value, return that value.
10040b57cec5SDimitry Andric     return PN->hasConstantValue();
10050b57cec5SDimitry Andric   }
10060b57cec5SDimitry Andric   return foldSelectInst(cast<SelectInst>(I));
10070b57cec5SDimitry Andric }
10080b57cec5SDimitry Andric 
10090b57cec5SDimitry Andric /// Builder for the alloca slices.
10100b57cec5SDimitry Andric ///
10110b57cec5SDimitry Andric /// This class builds a set of alloca slices by recursively visiting the uses
10120b57cec5SDimitry Andric /// of an alloca and making a slice for each load and store at each offset.
10130b57cec5SDimitry Andric class AllocaSlices::SliceBuilder : public PtrUseVisitor<SliceBuilder> {
10140b57cec5SDimitry Andric   friend class PtrUseVisitor<SliceBuilder>;
10150b57cec5SDimitry Andric   friend class InstVisitor<SliceBuilder>;
10160b57cec5SDimitry Andric 
10170b57cec5SDimitry Andric   using Base = PtrUseVisitor<SliceBuilder>;
10180b57cec5SDimitry Andric 
10190b57cec5SDimitry Andric   const uint64_t AllocSize;
10200b57cec5SDimitry Andric   AllocaSlices &AS;
10210b57cec5SDimitry Andric 
10220b57cec5SDimitry Andric   SmallDenseMap<Instruction *, unsigned> MemTransferSliceMap;
10230b57cec5SDimitry Andric   SmallDenseMap<Instruction *, uint64_t> PHIOrSelectSizes;
10240b57cec5SDimitry Andric 
10250b57cec5SDimitry Andric   /// Set to de-duplicate dead instructions found in the use walk.
10260b57cec5SDimitry Andric   SmallPtrSet<Instruction *, 4> VisitedDeadInsts;
10270b57cec5SDimitry Andric 
10280b57cec5SDimitry Andric public:
10290b57cec5SDimitry Andric   SliceBuilder(const DataLayout &DL, AllocaInst &AI, AllocaSlices &AS)
10300b57cec5SDimitry Andric       : PtrUseVisitor<SliceBuilder>(DL),
1031bdd1243dSDimitry Andric         AllocSize(DL.getTypeAllocSize(AI.getAllocatedType()).getFixedValue()),
10325ffd83dbSDimitry Andric         AS(AS) {}
10330b57cec5SDimitry Andric 
10340b57cec5SDimitry Andric private:
10350b57cec5SDimitry Andric   void markAsDead(Instruction &I) {
10360b57cec5SDimitry Andric     if (VisitedDeadInsts.insert(&I).second)
10370b57cec5SDimitry Andric       AS.DeadUsers.push_back(&I);
10380b57cec5SDimitry Andric   }
10390b57cec5SDimitry Andric 
10400b57cec5SDimitry Andric   void insertUse(Instruction &I, const APInt &Offset, uint64_t Size,
10410b57cec5SDimitry Andric                  bool IsSplittable = false) {
10420b57cec5SDimitry Andric     // Completely skip uses which have a zero size or start either before or
10430b57cec5SDimitry Andric     // past the end of the allocation.
10440b57cec5SDimitry Andric     if (Size == 0 || Offset.uge(AllocSize)) {
10450b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte use @"
10460b57cec5SDimitry Andric                         << Offset
10470b57cec5SDimitry Andric                         << " which has zero size or starts outside of the "
10480b57cec5SDimitry Andric                         << AllocSize << " byte alloca:\n"
10490b57cec5SDimitry Andric                         << "    alloca: " << AS.AI << "\n"
10500b57cec5SDimitry Andric                         << "       use: " << I << "\n");
10510b57cec5SDimitry Andric       return markAsDead(I);
10520b57cec5SDimitry Andric     }
10530b57cec5SDimitry Andric 
10540b57cec5SDimitry Andric     uint64_t BeginOffset = Offset.getZExtValue();
10550b57cec5SDimitry Andric     uint64_t EndOffset = BeginOffset + Size;
10560b57cec5SDimitry Andric 
10570b57cec5SDimitry Andric     // Clamp the end offset to the end of the allocation. Note that this is
10580b57cec5SDimitry Andric     // formulated to handle even the case where "BeginOffset + Size" overflows.
10590b57cec5SDimitry Andric     // This may appear superficially to be something we could ignore entirely,
10600b57cec5SDimitry Andric     // but that is not so! There may be widened loads or PHI-node uses where
10610b57cec5SDimitry Andric     // some instructions are dead but not others. We can't completely ignore
10620b57cec5SDimitry Andric     // them, and so have to record at least the information here.
10630b57cec5SDimitry Andric     assert(AllocSize >= BeginOffset); // Established above.
10640b57cec5SDimitry Andric     if (Size > AllocSize - BeginOffset) {
10650b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "WARNING: Clamping a " << Size << " byte use @"
10660b57cec5SDimitry Andric                         << Offset << " to remain within the " << AllocSize
10670b57cec5SDimitry Andric                         << " byte alloca:\n"
10680b57cec5SDimitry Andric                         << "    alloca: " << AS.AI << "\n"
10690b57cec5SDimitry Andric                         << "       use: " << I << "\n");
10700b57cec5SDimitry Andric       EndOffset = AllocSize;
10710b57cec5SDimitry Andric     }
10720b57cec5SDimitry Andric 
10730b57cec5SDimitry Andric     AS.Slices.push_back(Slice(BeginOffset, EndOffset, U, IsSplittable));
10740b57cec5SDimitry Andric   }
10750b57cec5SDimitry Andric 
10760b57cec5SDimitry Andric   void visitBitCastInst(BitCastInst &BC) {
10770b57cec5SDimitry Andric     if (BC.use_empty())
10780b57cec5SDimitry Andric       return markAsDead(BC);
10790b57cec5SDimitry Andric 
10800b57cec5SDimitry Andric     return Base::visitBitCastInst(BC);
10810b57cec5SDimitry Andric   }
10820b57cec5SDimitry Andric 
10830b57cec5SDimitry Andric   void visitAddrSpaceCastInst(AddrSpaceCastInst &ASC) {
10840b57cec5SDimitry Andric     if (ASC.use_empty())
10850b57cec5SDimitry Andric       return markAsDead(ASC);
10860b57cec5SDimitry Andric 
10870b57cec5SDimitry Andric     return Base::visitAddrSpaceCastInst(ASC);
10880b57cec5SDimitry Andric   }
10890b57cec5SDimitry Andric 
10900b57cec5SDimitry Andric   void visitGetElementPtrInst(GetElementPtrInst &GEPI) {
10910b57cec5SDimitry Andric     if (GEPI.use_empty())
10920b57cec5SDimitry Andric       return markAsDead(GEPI);
10930b57cec5SDimitry Andric 
10940b57cec5SDimitry Andric     return Base::visitGetElementPtrInst(GEPI);
10950b57cec5SDimitry Andric   }
10960b57cec5SDimitry Andric 
10970b57cec5SDimitry Andric   void handleLoadOrStore(Type *Ty, Instruction &I, const APInt &Offset,
10980b57cec5SDimitry Andric                          uint64_t Size, bool IsVolatile) {
10990b57cec5SDimitry Andric     // We allow splitting of non-volatile loads and stores where the type is an
11000b57cec5SDimitry Andric     // integer type. These may be used to implement 'memcpy' or other "transfer
11010b57cec5SDimitry Andric     // of bits" patterns.
1102fe6060f1SDimitry Andric     bool IsSplittable =
1103fe6060f1SDimitry Andric         Ty->isIntegerTy() && !IsVolatile && DL.typeSizeEqualsStoreSize(Ty);
11040b57cec5SDimitry Andric 
11050b57cec5SDimitry Andric     insertUse(I, Offset, Size, IsSplittable);
11060b57cec5SDimitry Andric   }
11070b57cec5SDimitry Andric 
11080b57cec5SDimitry Andric   void visitLoadInst(LoadInst &LI) {
11090b57cec5SDimitry Andric     assert((!LI.isSimple() || LI.getType()->isSingleValueType()) &&
11100b57cec5SDimitry Andric            "All simple FCA loads should have been pre-split");
11110b57cec5SDimitry Andric 
11120b57cec5SDimitry Andric     if (!IsOffsetKnown)
11130b57cec5SDimitry Andric       return PI.setAborted(&LI);
11140b57cec5SDimitry Andric 
111506c3fb27SDimitry Andric     TypeSize Size = DL.getTypeStoreSize(LI.getType());
111606c3fb27SDimitry Andric     if (Size.isScalable())
1117e8d8bef9SDimitry Andric       return PI.setAborted(&LI);
1118e8d8bef9SDimitry Andric 
111906c3fb27SDimitry Andric     return handleLoadOrStore(LI.getType(), LI, Offset, Size.getFixedValue(),
112006c3fb27SDimitry Andric                              LI.isVolatile());
11210b57cec5SDimitry Andric   }
11220b57cec5SDimitry Andric 
11230b57cec5SDimitry Andric   void visitStoreInst(StoreInst &SI) {
11240b57cec5SDimitry Andric     Value *ValOp = SI.getValueOperand();
11250b57cec5SDimitry Andric     if (ValOp == *U)
11260b57cec5SDimitry Andric       return PI.setEscapedAndAborted(&SI);
11270b57cec5SDimitry Andric     if (!IsOffsetKnown)
11280b57cec5SDimitry Andric       return PI.setAborted(&SI);
11290b57cec5SDimitry Andric 
113006c3fb27SDimitry Andric     TypeSize StoreSize = DL.getTypeStoreSize(ValOp->getType());
113106c3fb27SDimitry Andric     if (StoreSize.isScalable())
1132e8d8bef9SDimitry Andric       return PI.setAborted(&SI);
1133e8d8bef9SDimitry Andric 
113406c3fb27SDimitry Andric     uint64_t Size = StoreSize.getFixedValue();
11350b57cec5SDimitry Andric 
11360b57cec5SDimitry Andric     // If this memory access can be shown to *statically* extend outside the
11370b57cec5SDimitry Andric     // bounds of the allocation, it's behavior is undefined, so simply
11380b57cec5SDimitry Andric     // ignore it. Note that this is more strict than the generic clamping
11390b57cec5SDimitry Andric     // behavior of insertUse. We also try to handle cases which might run the
11400b57cec5SDimitry Andric     // risk of overflow.
11410b57cec5SDimitry Andric     // FIXME: We should instead consider the pointer to have escaped if this
11420b57cec5SDimitry Andric     // function is being instrumented for addressing bugs or race conditions.
11430b57cec5SDimitry Andric     if (Size > AllocSize || Offset.ugt(AllocSize - Size)) {
11440b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte store @"
11450b57cec5SDimitry Andric                         << Offset << " which extends past the end of the "
11460b57cec5SDimitry Andric                         << AllocSize << " byte alloca:\n"
11470b57cec5SDimitry Andric                         << "    alloca: " << AS.AI << "\n"
11480b57cec5SDimitry Andric                         << "       use: " << SI << "\n");
11490b57cec5SDimitry Andric       return markAsDead(SI);
11500b57cec5SDimitry Andric     }
11510b57cec5SDimitry Andric 
11520b57cec5SDimitry Andric     assert((!SI.isSimple() || ValOp->getType()->isSingleValueType()) &&
11530b57cec5SDimitry Andric            "All simple FCA stores should have been pre-split");
11540b57cec5SDimitry Andric     handleLoadOrStore(ValOp->getType(), SI, Offset, Size, SI.isVolatile());
11550b57cec5SDimitry Andric   }
11560b57cec5SDimitry Andric 
11570b57cec5SDimitry Andric   void visitMemSetInst(MemSetInst &II) {
11580b57cec5SDimitry Andric     assert(II.getRawDest() == *U && "Pointer use is not the destination?");
11590b57cec5SDimitry Andric     ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
11600b57cec5SDimitry Andric     if ((Length && Length->getValue() == 0) ||
11610b57cec5SDimitry Andric         (IsOffsetKnown && Offset.uge(AllocSize)))
11620b57cec5SDimitry Andric       // Zero-length mem transfer intrinsics can be ignored entirely.
11630b57cec5SDimitry Andric       return markAsDead(II);
11640b57cec5SDimitry Andric 
11650b57cec5SDimitry Andric     if (!IsOffsetKnown)
11660b57cec5SDimitry Andric       return PI.setAborted(&II);
11670b57cec5SDimitry Andric 
1168*0fca6ea1SDimitry Andric     insertUse(II, Offset,
1169*0fca6ea1SDimitry Andric               Length ? Length->getLimitedValue()
11700b57cec5SDimitry Andric                      : AllocSize - Offset.getLimitedValue(),
11710b57cec5SDimitry Andric               (bool)Length);
11720b57cec5SDimitry Andric   }
11730b57cec5SDimitry Andric 
11740b57cec5SDimitry Andric   void visitMemTransferInst(MemTransferInst &II) {
11750b57cec5SDimitry Andric     ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
11760b57cec5SDimitry Andric     if (Length && Length->getValue() == 0)
11770b57cec5SDimitry Andric       // Zero-length mem transfer intrinsics can be ignored entirely.
11780b57cec5SDimitry Andric       return markAsDead(II);
11790b57cec5SDimitry Andric 
11800b57cec5SDimitry Andric     // Because we can visit these intrinsics twice, also check to see if the
11810b57cec5SDimitry Andric     // first time marked this instruction as dead. If so, skip it.
11820b57cec5SDimitry Andric     if (VisitedDeadInsts.count(&II))
11830b57cec5SDimitry Andric       return;
11840b57cec5SDimitry Andric 
11850b57cec5SDimitry Andric     if (!IsOffsetKnown)
11860b57cec5SDimitry Andric       return PI.setAborted(&II);
11870b57cec5SDimitry Andric 
11880b57cec5SDimitry Andric     // This side of the transfer is completely out-of-bounds, and so we can
11890b57cec5SDimitry Andric     // nuke the entire transfer. However, we also need to nuke the other side
11900b57cec5SDimitry Andric     // if already added to our partitions.
11910b57cec5SDimitry Andric     // FIXME: Yet another place we really should bypass this when
11920b57cec5SDimitry Andric     // instrumenting for ASan.
11930b57cec5SDimitry Andric     if (Offset.uge(AllocSize)) {
11940b57cec5SDimitry Andric       SmallDenseMap<Instruction *, unsigned>::iterator MTPI =
11950b57cec5SDimitry Andric           MemTransferSliceMap.find(&II);
11960b57cec5SDimitry Andric       if (MTPI != MemTransferSliceMap.end())
11970b57cec5SDimitry Andric         AS.Slices[MTPI->second].kill();
11980b57cec5SDimitry Andric       return markAsDead(II);
11990b57cec5SDimitry Andric     }
12000b57cec5SDimitry Andric 
12010b57cec5SDimitry Andric     uint64_t RawOffset = Offset.getLimitedValue();
12020b57cec5SDimitry Andric     uint64_t Size = Length ? Length->getLimitedValue() : AllocSize - RawOffset;
12030b57cec5SDimitry Andric 
12040b57cec5SDimitry Andric     // Check for the special case where the same exact value is used for both
12050b57cec5SDimitry Andric     // source and dest.
12060b57cec5SDimitry Andric     if (*U == II.getRawDest() && *U == II.getRawSource()) {
12070b57cec5SDimitry Andric       // For non-volatile transfers this is a no-op.
12080b57cec5SDimitry Andric       if (!II.isVolatile())
12090b57cec5SDimitry Andric         return markAsDead(II);
12100b57cec5SDimitry Andric 
12110b57cec5SDimitry Andric       return insertUse(II, Offset, Size, /*IsSplittable=*/false);
12120b57cec5SDimitry Andric     }
12130b57cec5SDimitry Andric 
12140b57cec5SDimitry Andric     // If we have seen both source and destination for a mem transfer, then
12150b57cec5SDimitry Andric     // they both point to the same alloca.
12160b57cec5SDimitry Andric     bool Inserted;
12170b57cec5SDimitry Andric     SmallDenseMap<Instruction *, unsigned>::iterator MTPI;
12180b57cec5SDimitry Andric     std::tie(MTPI, Inserted) =
12190b57cec5SDimitry Andric         MemTransferSliceMap.insert(std::make_pair(&II, AS.Slices.size()));
12200b57cec5SDimitry Andric     unsigned PrevIdx = MTPI->second;
12210b57cec5SDimitry Andric     if (!Inserted) {
12220b57cec5SDimitry Andric       Slice &PrevP = AS.Slices[PrevIdx];
12230b57cec5SDimitry Andric 
12240b57cec5SDimitry Andric       // Check if the begin offsets match and this is a non-volatile transfer.
12250b57cec5SDimitry Andric       // In that case, we can completely elide the transfer.
12260b57cec5SDimitry Andric       if (!II.isVolatile() && PrevP.beginOffset() == RawOffset) {
12270b57cec5SDimitry Andric         PrevP.kill();
12280b57cec5SDimitry Andric         return markAsDead(II);
12290b57cec5SDimitry Andric       }
12300b57cec5SDimitry Andric 
12310b57cec5SDimitry Andric       // Otherwise we have an offset transfer within the same alloca. We can't
12320b57cec5SDimitry Andric       // split those.
12330b57cec5SDimitry Andric       PrevP.makeUnsplittable();
12340b57cec5SDimitry Andric     }
12350b57cec5SDimitry Andric 
12360b57cec5SDimitry Andric     // Insert the use now that we've fixed up the splittable nature.
12370b57cec5SDimitry Andric     insertUse(II, Offset, Size, /*IsSplittable=*/Inserted && Length);
12380b57cec5SDimitry Andric 
12390b57cec5SDimitry Andric     // Check that we ended up with a valid index in the map.
12400b57cec5SDimitry Andric     assert(AS.Slices[PrevIdx].getUse()->getUser() == &II &&
12410b57cec5SDimitry Andric            "Map index doesn't point back to a slice with this user.");
12420b57cec5SDimitry Andric   }
12430b57cec5SDimitry Andric 
1244fe6060f1SDimitry Andric   // Disable SRoA for any intrinsics except for lifetime invariants and
1245fe6060f1SDimitry Andric   // invariant group.
12460b57cec5SDimitry Andric   // FIXME: What about debug intrinsics? This matches old behavior, but
12470b57cec5SDimitry Andric   // doesn't make sense.
12480b57cec5SDimitry Andric   void visitIntrinsicInst(IntrinsicInst &II) {
1249e8d8bef9SDimitry Andric     if (II.isDroppable()) {
1250e8d8bef9SDimitry Andric       AS.DeadUseIfPromotable.push_back(U);
1251e8d8bef9SDimitry Andric       return;
1252e8d8bef9SDimitry Andric     }
1253e8d8bef9SDimitry Andric 
12540b57cec5SDimitry Andric     if (!IsOffsetKnown)
12550b57cec5SDimitry Andric       return PI.setAborted(&II);
12560b57cec5SDimitry Andric 
12570b57cec5SDimitry Andric     if (II.isLifetimeStartOrEnd()) {
12580b57cec5SDimitry Andric       ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
12590b57cec5SDimitry Andric       uint64_t Size = std::min(AllocSize - Offset.getLimitedValue(),
12600b57cec5SDimitry Andric                                Length->getLimitedValue());
12610b57cec5SDimitry Andric       insertUse(II, Offset, Size, true);
12620b57cec5SDimitry Andric       return;
12630b57cec5SDimitry Andric     }
12640b57cec5SDimitry Andric 
1265fe6060f1SDimitry Andric     if (II.isLaunderOrStripInvariantGroup()) {
12665f757f3fSDimitry Andric       insertUse(II, Offset, AllocSize, true);
1267fe6060f1SDimitry Andric       enqueueUsers(II);
1268fe6060f1SDimitry Andric       return;
1269fe6060f1SDimitry Andric     }
1270fe6060f1SDimitry Andric 
12710b57cec5SDimitry Andric     Base::visitIntrinsicInst(II);
12720b57cec5SDimitry Andric   }
12730b57cec5SDimitry Andric 
12740b57cec5SDimitry Andric   Instruction *hasUnsafePHIOrSelectUse(Instruction *Root, uint64_t &Size) {
12750b57cec5SDimitry Andric     // We consider any PHI or select that results in a direct load or store of
12760b57cec5SDimitry Andric     // the same offset to be a viable use for slicing purposes. These uses
12770b57cec5SDimitry Andric     // are considered unsplittable and the size is the maximum loaded or stored
12780b57cec5SDimitry Andric     // size.
12790b57cec5SDimitry Andric     SmallPtrSet<Instruction *, 4> Visited;
12800b57cec5SDimitry Andric     SmallVector<std::pair<Instruction *, Instruction *>, 4> Uses;
12810b57cec5SDimitry Andric     Visited.insert(Root);
12820b57cec5SDimitry Andric     Uses.push_back(std::make_pair(cast<Instruction>(*U), Root));
1283*0fca6ea1SDimitry Andric     const DataLayout &DL = Root->getDataLayout();
12840b57cec5SDimitry Andric     // If there are no loads or stores, the access is dead. We mark that as
12850b57cec5SDimitry Andric     // a size zero access.
12860b57cec5SDimitry Andric     Size = 0;
12870b57cec5SDimitry Andric     do {
12880b57cec5SDimitry Andric       Instruction *I, *UsedI;
12890b57cec5SDimitry Andric       std::tie(UsedI, I) = Uses.pop_back_val();
12900b57cec5SDimitry Andric 
12910b57cec5SDimitry Andric       if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
12925f757f3fSDimitry Andric         TypeSize LoadSize = DL.getTypeStoreSize(LI->getType());
12935f757f3fSDimitry Andric         if (LoadSize.isScalable()) {
12945f757f3fSDimitry Andric           PI.setAborted(LI);
12955f757f3fSDimitry Andric           return nullptr;
12965f757f3fSDimitry Andric         }
12975f757f3fSDimitry Andric         Size = std::max(Size, LoadSize.getFixedValue());
12980b57cec5SDimitry Andric         continue;
12990b57cec5SDimitry Andric       }
13000b57cec5SDimitry Andric       if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
13010b57cec5SDimitry Andric         Value *Op = SI->getOperand(0);
13020b57cec5SDimitry Andric         if (Op == UsedI)
13030b57cec5SDimitry Andric           return SI;
13045f757f3fSDimitry Andric         TypeSize StoreSize = DL.getTypeStoreSize(Op->getType());
13055f757f3fSDimitry Andric         if (StoreSize.isScalable()) {
13065f757f3fSDimitry Andric           PI.setAborted(SI);
13075f757f3fSDimitry Andric           return nullptr;
13085f757f3fSDimitry Andric         }
13095f757f3fSDimitry Andric         Size = std::max(Size, StoreSize.getFixedValue());
13100b57cec5SDimitry Andric         continue;
13110b57cec5SDimitry Andric       }
13120b57cec5SDimitry Andric 
13130b57cec5SDimitry Andric       if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
13140b57cec5SDimitry Andric         if (!GEP->hasAllZeroIndices())
13150b57cec5SDimitry Andric           return GEP;
13160b57cec5SDimitry Andric       } else if (!isa<BitCastInst>(I) && !isa<PHINode>(I) &&
13170b57cec5SDimitry Andric                  !isa<SelectInst>(I) && !isa<AddrSpaceCastInst>(I)) {
13180b57cec5SDimitry Andric         return I;
13190b57cec5SDimitry Andric       }
13200b57cec5SDimitry Andric 
13210b57cec5SDimitry Andric       for (User *U : I->users())
13220b57cec5SDimitry Andric         if (Visited.insert(cast<Instruction>(U)).second)
13230b57cec5SDimitry Andric           Uses.push_back(std::make_pair(I, cast<Instruction>(U)));
13240b57cec5SDimitry Andric     } while (!Uses.empty());
13250b57cec5SDimitry Andric 
13260b57cec5SDimitry Andric     return nullptr;
13270b57cec5SDimitry Andric   }
13280b57cec5SDimitry Andric 
13290b57cec5SDimitry Andric   void visitPHINodeOrSelectInst(Instruction &I) {
13300b57cec5SDimitry Andric     assert(isa<PHINode>(I) || isa<SelectInst>(I));
13310b57cec5SDimitry Andric     if (I.use_empty())
13320b57cec5SDimitry Andric       return markAsDead(I);
13330b57cec5SDimitry Andric 
133404eeddc0SDimitry Andric     // If this is a PHI node before a catchswitch, we cannot insert any non-PHI
133504eeddc0SDimitry Andric     // instructions in this BB, which may be required during rewriting. Bail out
133604eeddc0SDimitry Andric     // on these cases.
133704eeddc0SDimitry Andric     if (isa<PHINode>(I) &&
133804eeddc0SDimitry Andric         I.getParent()->getFirstInsertionPt() == I.getParent()->end())
133904eeddc0SDimitry Andric       return PI.setAborted(&I);
134004eeddc0SDimitry Andric 
134181ad6265SDimitry Andric     // TODO: We could use simplifyInstruction here to fold PHINodes and
13420b57cec5SDimitry Andric     // SelectInsts. However, doing so requires to change the current
13430b57cec5SDimitry Andric     // dead-operand-tracking mechanism. For instance, suppose neither loading
13440b57cec5SDimitry Andric     // from %U nor %other traps. Then "load (select undef, %U, %other)" does not
13450b57cec5SDimitry Andric     // trap either.  However, if we simply replace %U with undef using the
13460b57cec5SDimitry Andric     // current dead-operand-tracking mechanism, "load (select undef, undef,
13470b57cec5SDimitry Andric     // %other)" may trap because the select may return the first operand
13480b57cec5SDimitry Andric     // "undef".
13490b57cec5SDimitry Andric     if (Value *Result = foldPHINodeOrSelectInst(I)) {
13500b57cec5SDimitry Andric       if (Result == *U)
13510b57cec5SDimitry Andric         // If the result of the constant fold will be the pointer, recurse
13520b57cec5SDimitry Andric         // through the PHI/select as if we had RAUW'ed it.
13530b57cec5SDimitry Andric         enqueueUsers(I);
13540b57cec5SDimitry Andric       else
13550b57cec5SDimitry Andric         // Otherwise the operand to the PHI/select is dead, and we can replace
135604eeddc0SDimitry Andric         // it with poison.
13570b57cec5SDimitry Andric         AS.DeadOperands.push_back(U);
13580b57cec5SDimitry Andric 
13590b57cec5SDimitry Andric       return;
13600b57cec5SDimitry Andric     }
13610b57cec5SDimitry Andric 
13620b57cec5SDimitry Andric     if (!IsOffsetKnown)
13630b57cec5SDimitry Andric       return PI.setAborted(&I);
13640b57cec5SDimitry Andric 
13650b57cec5SDimitry Andric     // See if we already have computed info on this node.
13660b57cec5SDimitry Andric     uint64_t &Size = PHIOrSelectSizes[&I];
13670b57cec5SDimitry Andric     if (!Size) {
13680b57cec5SDimitry Andric       // This is a new PHI/Select, check for an unsafe use of it.
13690b57cec5SDimitry Andric       if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&I, Size))
13700b57cec5SDimitry Andric         return PI.setAborted(UnsafeI);
13710b57cec5SDimitry Andric     }
13720b57cec5SDimitry Andric 
13730b57cec5SDimitry Andric     // For PHI and select operands outside the alloca, we can't nuke the entire
13740b57cec5SDimitry Andric     // phi or select -- the other side might still be relevant, so we special
13750b57cec5SDimitry Andric     // case them here and use a separate structure to track the operands
137604eeddc0SDimitry Andric     // themselves which should be replaced with poison.
13770b57cec5SDimitry Andric     // FIXME: This should instead be escaped in the event we're instrumenting
13780b57cec5SDimitry Andric     // for address sanitization.
13790b57cec5SDimitry Andric     if (Offset.uge(AllocSize)) {
13800b57cec5SDimitry Andric       AS.DeadOperands.push_back(U);
13810b57cec5SDimitry Andric       return;
13820b57cec5SDimitry Andric     }
13830b57cec5SDimitry Andric 
13840b57cec5SDimitry Andric     insertUse(I, Offset, Size);
13850b57cec5SDimitry Andric   }
13860b57cec5SDimitry Andric 
13870b57cec5SDimitry Andric   void visitPHINode(PHINode &PN) { visitPHINodeOrSelectInst(PN); }
13880b57cec5SDimitry Andric 
13890b57cec5SDimitry Andric   void visitSelectInst(SelectInst &SI) { visitPHINodeOrSelectInst(SI); }
13900b57cec5SDimitry Andric 
13910b57cec5SDimitry Andric   /// Disable SROA entirely if there are unhandled users of the alloca.
13920b57cec5SDimitry Andric   void visitInstruction(Instruction &I) { PI.setAborted(&I); }
13930b57cec5SDimitry Andric };
13940b57cec5SDimitry Andric 
13950b57cec5SDimitry Andric AllocaSlices::AllocaSlices(const DataLayout &DL, AllocaInst &AI)
13960b57cec5SDimitry Andric     :
13970b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
13980b57cec5SDimitry Andric       AI(AI),
13990b57cec5SDimitry Andric #endif
14000b57cec5SDimitry Andric       PointerEscapingInstr(nullptr) {
14010b57cec5SDimitry Andric   SliceBuilder PB(DL, AI, *this);
14020b57cec5SDimitry Andric   SliceBuilder::PtrInfo PtrI = PB.visitPtr(AI);
14030b57cec5SDimitry Andric   if (PtrI.isEscaped() || PtrI.isAborted()) {
14040b57cec5SDimitry Andric     // FIXME: We should sink the escape vs. abort info into the caller nicely,
14050b57cec5SDimitry Andric     // possibly by just storing the PtrInfo in the AllocaSlices.
14060b57cec5SDimitry Andric     PointerEscapingInstr = PtrI.getEscapingInst() ? PtrI.getEscapingInst()
14070b57cec5SDimitry Andric                                                   : PtrI.getAbortingInst();
14080b57cec5SDimitry Andric     assert(PointerEscapingInstr && "Did not track a bad instruction");
14090b57cec5SDimitry Andric     return;
14100b57cec5SDimitry Andric   }
14110b57cec5SDimitry Andric 
1412e8d8bef9SDimitry Andric   llvm::erase_if(Slices, [](const Slice &S) { return S.isDead(); });
14130b57cec5SDimitry Andric 
14140b57cec5SDimitry Andric   // Sort the uses. This arranges for the offsets to be in ascending order,
14150b57cec5SDimitry Andric   // and the sizes to be in descending order.
1416e8d8bef9SDimitry Andric   llvm::stable_sort(Slices);
14170b57cec5SDimitry Andric }
14180b57cec5SDimitry Andric 
14190b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
14200b57cec5SDimitry Andric 
14210b57cec5SDimitry Andric void AllocaSlices::print(raw_ostream &OS, const_iterator I,
14220b57cec5SDimitry Andric                          StringRef Indent) const {
14230b57cec5SDimitry Andric   printSlice(OS, I, Indent);
14240b57cec5SDimitry Andric   OS << "\n";
14250b57cec5SDimitry Andric   printUse(OS, I, Indent);
14260b57cec5SDimitry Andric }
14270b57cec5SDimitry Andric 
14280b57cec5SDimitry Andric void AllocaSlices::printSlice(raw_ostream &OS, const_iterator I,
14290b57cec5SDimitry Andric                               StringRef Indent) const {
14300b57cec5SDimitry Andric   OS << Indent << "[" << I->beginOffset() << "," << I->endOffset() << ")"
14310b57cec5SDimitry Andric      << " slice #" << (I - begin())
14320b57cec5SDimitry Andric      << (I->isSplittable() ? " (splittable)" : "");
14330b57cec5SDimitry Andric }
14340b57cec5SDimitry Andric 
14350b57cec5SDimitry Andric void AllocaSlices::printUse(raw_ostream &OS, const_iterator I,
14360b57cec5SDimitry Andric                             StringRef Indent) const {
14370b57cec5SDimitry Andric   OS << Indent << "  used by: " << *I->getUse()->getUser() << "\n";
14380b57cec5SDimitry Andric }
14390b57cec5SDimitry Andric 
14400b57cec5SDimitry Andric void AllocaSlices::print(raw_ostream &OS) const {
14410b57cec5SDimitry Andric   if (PointerEscapingInstr) {
14420b57cec5SDimitry Andric     OS << "Can't analyze slices for alloca: " << AI << "\n"
14430b57cec5SDimitry Andric        << "  A pointer to this alloca escaped by:\n"
14440b57cec5SDimitry Andric        << "  " << *PointerEscapingInstr << "\n";
14450b57cec5SDimitry Andric     return;
14460b57cec5SDimitry Andric   }
14470b57cec5SDimitry Andric 
14480b57cec5SDimitry Andric   OS << "Slices of alloca: " << AI << "\n";
14490b57cec5SDimitry Andric   for (const_iterator I = begin(), E = end(); I != E; ++I)
14500b57cec5SDimitry Andric     print(OS, I);
14510b57cec5SDimitry Andric }
14520b57cec5SDimitry Andric 
14530b57cec5SDimitry Andric LLVM_DUMP_METHOD void AllocaSlices::dump(const_iterator I) const {
14540b57cec5SDimitry Andric   print(dbgs(), I);
14550b57cec5SDimitry Andric }
14560b57cec5SDimitry Andric LLVM_DUMP_METHOD void AllocaSlices::dump() const { print(dbgs()); }
14570b57cec5SDimitry Andric 
14580b57cec5SDimitry Andric #endif // !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
14590b57cec5SDimitry Andric 
14600b57cec5SDimitry Andric /// Walk the range of a partitioning looking for a common type to cover this
14610b57cec5SDimitry Andric /// sequence of slices.
1462e8d8bef9SDimitry Andric static std::pair<Type *, IntegerType *>
1463e8d8bef9SDimitry Andric findCommonType(AllocaSlices::const_iterator B, AllocaSlices::const_iterator E,
14640b57cec5SDimitry Andric                uint64_t EndOffset) {
14650b57cec5SDimitry Andric   Type *Ty = nullptr;
14660b57cec5SDimitry Andric   bool TyIsCommon = true;
14670b57cec5SDimitry Andric   IntegerType *ITy = nullptr;
14680b57cec5SDimitry Andric 
14690b57cec5SDimitry Andric   // Note that we need to look at *every* alloca slice's Use to ensure we
14700b57cec5SDimitry Andric   // always get consistent results regardless of the order of slices.
14710b57cec5SDimitry Andric   for (AllocaSlices::const_iterator I = B; I != E; ++I) {
14720b57cec5SDimitry Andric     Use *U = I->getUse();
14730b57cec5SDimitry Andric     if (isa<IntrinsicInst>(*U->getUser()))
14740b57cec5SDimitry Andric       continue;
14750b57cec5SDimitry Andric     if (I->beginOffset() != B->beginOffset() || I->endOffset() != EndOffset)
14760b57cec5SDimitry Andric       continue;
14770b57cec5SDimitry Andric 
14780b57cec5SDimitry Andric     Type *UserTy = nullptr;
14790b57cec5SDimitry Andric     if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
14800b57cec5SDimitry Andric       UserTy = LI->getType();
14810b57cec5SDimitry Andric     } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
14820b57cec5SDimitry Andric       UserTy = SI->getValueOperand()->getType();
14830b57cec5SDimitry Andric     }
14840b57cec5SDimitry Andric 
14850b57cec5SDimitry Andric     if (IntegerType *UserITy = dyn_cast_or_null<IntegerType>(UserTy)) {
14860b57cec5SDimitry Andric       // If the type is larger than the partition, skip it. We only encounter
14870b57cec5SDimitry Andric       // this for split integer operations where we want to use the type of the
14880b57cec5SDimitry Andric       // entity causing the split. Also skip if the type is not a byte width
14890b57cec5SDimitry Andric       // multiple.
14900b57cec5SDimitry Andric       if (UserITy->getBitWidth() % 8 != 0 ||
14910b57cec5SDimitry Andric           UserITy->getBitWidth() / 8 > (EndOffset - B->beginOffset()))
14920b57cec5SDimitry Andric         continue;
14930b57cec5SDimitry Andric 
14940b57cec5SDimitry Andric       // Track the largest bitwidth integer type used in this way in case there
14950b57cec5SDimitry Andric       // is no common type.
14960b57cec5SDimitry Andric       if (!ITy || ITy->getBitWidth() < UserITy->getBitWidth())
14970b57cec5SDimitry Andric         ITy = UserITy;
14980b57cec5SDimitry Andric     }
14990b57cec5SDimitry Andric 
15000b57cec5SDimitry Andric     // To avoid depending on the order of slices, Ty and TyIsCommon must not
15010b57cec5SDimitry Andric     // depend on types skipped above.
15020b57cec5SDimitry Andric     if (!UserTy || (Ty && Ty != UserTy))
15030b57cec5SDimitry Andric       TyIsCommon = false; // Give up on anything but an iN type.
15040b57cec5SDimitry Andric     else
15050b57cec5SDimitry Andric       Ty = UserTy;
15060b57cec5SDimitry Andric   }
15070b57cec5SDimitry Andric 
1508e8d8bef9SDimitry Andric   return {TyIsCommon ? Ty : nullptr, ITy};
15090b57cec5SDimitry Andric }
15100b57cec5SDimitry Andric 
15110b57cec5SDimitry Andric /// PHI instructions that use an alloca and are subsequently loaded can be
15120b57cec5SDimitry Andric /// rewritten to load both input pointers in the pred blocks and then PHI the
15130b57cec5SDimitry Andric /// results, allowing the load of the alloca to be promoted.
15140b57cec5SDimitry Andric /// From this:
15150b57cec5SDimitry Andric ///   %P2 = phi [i32* %Alloca, i32* %Other]
15160b57cec5SDimitry Andric ///   %V = load i32* %P2
15170b57cec5SDimitry Andric /// to:
15180b57cec5SDimitry Andric ///   %V1 = load i32* %Alloca      -> will be mem2reg'd
15190b57cec5SDimitry Andric ///   ...
15200b57cec5SDimitry Andric ///   %V2 = load i32* %Other
15210b57cec5SDimitry Andric ///   ...
15220b57cec5SDimitry Andric ///   %V = phi [i32 %V1, i32 %V2]
15230b57cec5SDimitry Andric ///
15240b57cec5SDimitry Andric /// We can do this to a select if its only uses are loads and if the operands
15250b57cec5SDimitry Andric /// to the select can be loaded unconditionally.
15260b57cec5SDimitry Andric ///
15270b57cec5SDimitry Andric /// FIXME: This should be hoisted into a generic utility, likely in
15280b57cec5SDimitry Andric /// Transforms/Util/Local.h
15290b57cec5SDimitry Andric static bool isSafePHIToSpeculate(PHINode &PN) {
1530*0fca6ea1SDimitry Andric   const DataLayout &DL = PN.getDataLayout();
15310b57cec5SDimitry Andric 
15320b57cec5SDimitry Andric   // For now, we can only do this promotion if the load is in the same block
15330b57cec5SDimitry Andric   // as the PHI, and if there are no stores between the phi and load.
15340b57cec5SDimitry Andric   // TODO: Allow recursive phi users.
15350b57cec5SDimitry Andric   // TODO: Allow stores.
15360b57cec5SDimitry Andric   BasicBlock *BB = PN.getParent();
15375ffd83dbSDimitry Andric   Align MaxAlign;
15380b57cec5SDimitry Andric   uint64_t APWidth = DL.getIndexTypeSizeInBits(PN.getType());
1539f3fd488fSDimitry Andric   Type *LoadType = nullptr;
15400b57cec5SDimitry Andric   for (User *U : PN.users()) {
15410b57cec5SDimitry Andric     LoadInst *LI = dyn_cast<LoadInst>(U);
15420b57cec5SDimitry Andric     if (!LI || !LI->isSimple())
15430b57cec5SDimitry Andric       return false;
15440b57cec5SDimitry Andric 
15450b57cec5SDimitry Andric     // For now we only allow loads in the same block as the PHI.  This is
15460b57cec5SDimitry Andric     // a common case that happens when instcombine merges two loads through
15470b57cec5SDimitry Andric     // a PHI.
15480b57cec5SDimitry Andric     if (LI->getParent() != BB)
15490b57cec5SDimitry Andric       return false;
15500b57cec5SDimitry Andric 
1551f3fd488fSDimitry Andric     if (LoadType) {
1552f3fd488fSDimitry Andric       if (LoadType != LI->getType())
1553f3fd488fSDimitry Andric         return false;
1554f3fd488fSDimitry Andric     } else {
1555f3fd488fSDimitry Andric       LoadType = LI->getType();
1556f3fd488fSDimitry Andric     }
1557f3fd488fSDimitry Andric 
15580b57cec5SDimitry Andric     // Ensure that there are no instructions between the PHI and the load that
15590b57cec5SDimitry Andric     // could store.
15600b57cec5SDimitry Andric     for (BasicBlock::iterator BBI(PN); &*BBI != LI; ++BBI)
15610b57cec5SDimitry Andric       if (BBI->mayWriteToMemory())
15620b57cec5SDimitry Andric         return false;
15630b57cec5SDimitry Andric 
15645ffd83dbSDimitry Andric     MaxAlign = std::max(MaxAlign, LI->getAlign());
15650b57cec5SDimitry Andric   }
15660b57cec5SDimitry Andric 
1567f3fd488fSDimitry Andric   if (!LoadType)
15680b57cec5SDimitry Andric     return false;
15690b57cec5SDimitry Andric 
1570bdd1243dSDimitry Andric   APInt LoadSize =
1571bdd1243dSDimitry Andric       APInt(APWidth, DL.getTypeStoreSize(LoadType).getFixedValue());
1572f3fd488fSDimitry Andric 
15730b57cec5SDimitry Andric   // We can only transform this if it is safe to push the loads into the
15740b57cec5SDimitry Andric   // predecessor blocks. The only thing to watch out for is that we can't put
15750b57cec5SDimitry Andric   // a possibly trapping load in the predecessor if it is a critical edge.
15760b57cec5SDimitry Andric   for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
15770b57cec5SDimitry Andric     Instruction *TI = PN.getIncomingBlock(Idx)->getTerminator();
15780b57cec5SDimitry Andric     Value *InVal = PN.getIncomingValue(Idx);
15790b57cec5SDimitry Andric 
15800b57cec5SDimitry Andric     // If the value is produced by the terminator of the predecessor (an
15810b57cec5SDimitry Andric     // invoke) or it has side-effects, there is no valid place to put a load
15820b57cec5SDimitry Andric     // in the predecessor.
15830b57cec5SDimitry Andric     if (TI == InVal || TI->mayHaveSideEffects())
15840b57cec5SDimitry Andric       return false;
15850b57cec5SDimitry Andric 
15860b57cec5SDimitry Andric     // If the predecessor has a single successor, then the edge isn't
15870b57cec5SDimitry Andric     // critical.
15880b57cec5SDimitry Andric     if (TI->getNumSuccessors() == 1)
15890b57cec5SDimitry Andric       continue;
15900b57cec5SDimitry Andric 
15910b57cec5SDimitry Andric     // If this pointer is always safe to load, or if we can prove that there
15920b57cec5SDimitry Andric     // is already a load in the block, then we can move the load to the pred
15930b57cec5SDimitry Andric     // block.
1594f3fd488fSDimitry Andric     if (isSafeToLoadUnconditionally(InVal, MaxAlign, LoadSize, DL, TI))
15950b57cec5SDimitry Andric       continue;
15960b57cec5SDimitry Andric 
15970b57cec5SDimitry Andric     return false;
15980b57cec5SDimitry Andric   }
15990b57cec5SDimitry Andric 
16000b57cec5SDimitry Andric   return true;
16010b57cec5SDimitry Andric }
16020b57cec5SDimitry Andric 
160304eeddc0SDimitry Andric static void speculatePHINodeLoads(IRBuilderTy &IRB, PHINode &PN) {
16040b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "    original: " << PN << "\n");
16050b57cec5SDimitry Andric 
16060b57cec5SDimitry Andric   LoadInst *SomeLoad = cast<LoadInst>(PN.user_back());
16070b57cec5SDimitry Andric   Type *LoadTy = SomeLoad->getType();
160804eeddc0SDimitry Andric   IRB.SetInsertPoint(&PN);
160904eeddc0SDimitry Andric   PHINode *NewPN = IRB.CreatePHI(LoadTy, PN.getNumIncomingValues(),
16100b57cec5SDimitry Andric                                  PN.getName() + ".sroa.speculated");
16110b57cec5SDimitry Andric 
16128bcb0991SDimitry Andric   // Get the AA tags and alignment to use from one of the loads. It does not
16130b57cec5SDimitry Andric   // matter which one we get and if any differ.
1614349cc55cSDimitry Andric   AAMDNodes AATags = SomeLoad->getAAMetadata();
16155ffd83dbSDimitry Andric   Align Alignment = SomeLoad->getAlign();
16160b57cec5SDimitry Andric 
16170b57cec5SDimitry Andric   // Rewrite all loads of the PN to use the new PHI.
16180b57cec5SDimitry Andric   while (!PN.use_empty()) {
16190b57cec5SDimitry Andric     LoadInst *LI = cast<LoadInst>(PN.user_back());
16200b57cec5SDimitry Andric     LI->replaceAllUsesWith(NewPN);
16210b57cec5SDimitry Andric     LI->eraseFromParent();
16220b57cec5SDimitry Andric   }
16230b57cec5SDimitry Andric 
16240b57cec5SDimitry Andric   // Inject loads into all of the pred blocks.
16250b57cec5SDimitry Andric   DenseMap<BasicBlock *, Value *> InjectedLoads;
16260b57cec5SDimitry Andric   for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
16270b57cec5SDimitry Andric     BasicBlock *Pred = PN.getIncomingBlock(Idx);
16280b57cec5SDimitry Andric     Value *InVal = PN.getIncomingValue(Idx);
16290b57cec5SDimitry Andric 
16300b57cec5SDimitry Andric     // A PHI node is allowed to have multiple (duplicated) entries for the same
16310b57cec5SDimitry Andric     // basic block, as long as the value is the same. So if we already injected
16320b57cec5SDimitry Andric     // a load in the predecessor, then we should reuse the same load for all
16330b57cec5SDimitry Andric     // duplicated entries.
16340b57cec5SDimitry Andric     if (Value *V = InjectedLoads.lookup(Pred)) {
16350b57cec5SDimitry Andric       NewPN->addIncoming(V, Pred);
16360b57cec5SDimitry Andric       continue;
16370b57cec5SDimitry Andric     }
16380b57cec5SDimitry Andric 
16390b57cec5SDimitry Andric     Instruction *TI = Pred->getTerminator();
164004eeddc0SDimitry Andric     IRB.SetInsertPoint(TI);
16410b57cec5SDimitry Andric 
164204eeddc0SDimitry Andric     LoadInst *Load = IRB.CreateAlignedLoad(
16435ffd83dbSDimitry Andric         LoadTy, InVal, Alignment,
16440b57cec5SDimitry Andric         (PN.getName() + ".sroa.speculate.load." + Pred->getName()));
16450b57cec5SDimitry Andric     ++NumLoadsSpeculated;
16460b57cec5SDimitry Andric     if (AATags)
16470b57cec5SDimitry Andric       Load->setAAMetadata(AATags);
16480b57cec5SDimitry Andric     NewPN->addIncoming(Load, Pred);
16490b57cec5SDimitry Andric     InjectedLoads[Pred] = Load;
16500b57cec5SDimitry Andric   }
16510b57cec5SDimitry Andric 
16520b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "          speculated to: " << *NewPN << "\n");
16530b57cec5SDimitry Andric   PN.eraseFromParent();
16540b57cec5SDimitry Andric }
16550b57cec5SDimitry Andric 
16565f757f3fSDimitry Andric SelectHandSpeculativity &
16575f757f3fSDimitry Andric SelectHandSpeculativity::setAsSpeculatable(bool isTrueVal) {
1658bdd1243dSDimitry Andric   if (isTrueVal)
16595f757f3fSDimitry Andric     Bitfield::set<SelectHandSpeculativity::TrueVal>(Storage, true);
1660bdd1243dSDimitry Andric   else
16615f757f3fSDimitry Andric     Bitfield::set<SelectHandSpeculativity::FalseVal>(Storage, true);
1662bdd1243dSDimitry Andric   return *this;
1663bdd1243dSDimitry Andric }
1664bdd1243dSDimitry Andric 
16655f757f3fSDimitry Andric bool SelectHandSpeculativity::isSpeculatable(bool isTrueVal) const {
16665f757f3fSDimitry Andric   return isTrueVal ? Bitfield::get<SelectHandSpeculativity::TrueVal>(Storage)
16675f757f3fSDimitry Andric                    : Bitfield::get<SelectHandSpeculativity::FalseVal>(Storage);
1668bdd1243dSDimitry Andric }
1669bdd1243dSDimitry Andric 
16705f757f3fSDimitry Andric bool SelectHandSpeculativity::areAllSpeculatable() const {
1671bdd1243dSDimitry Andric   return isSpeculatable(/*isTrueVal=*/true) &&
1672bdd1243dSDimitry Andric          isSpeculatable(/*isTrueVal=*/false);
1673bdd1243dSDimitry Andric }
1674bdd1243dSDimitry Andric 
16755f757f3fSDimitry Andric bool SelectHandSpeculativity::areAnySpeculatable() const {
1676bdd1243dSDimitry Andric   return isSpeculatable(/*isTrueVal=*/true) ||
1677bdd1243dSDimitry Andric          isSpeculatable(/*isTrueVal=*/false);
1678bdd1243dSDimitry Andric }
16795f757f3fSDimitry Andric bool SelectHandSpeculativity::areNoneSpeculatable() const {
1680bdd1243dSDimitry Andric   return !areAnySpeculatable();
1681bdd1243dSDimitry Andric }
1682bdd1243dSDimitry Andric 
16835f757f3fSDimitry Andric static SelectHandSpeculativity
1684bdd1243dSDimitry Andric isSafeLoadOfSelectToSpeculate(LoadInst &LI, SelectInst &SI, bool PreserveCFG) {
1685bdd1243dSDimitry Andric   assert(LI.isSimple() && "Only for simple loads");
16865f757f3fSDimitry Andric   SelectHandSpeculativity Spec;
1687bdd1243dSDimitry Andric 
1688*0fca6ea1SDimitry Andric   const DataLayout &DL = SI.getDataLayout();
1689bdd1243dSDimitry Andric   for (Value *Value : {SI.getTrueValue(), SI.getFalseValue()})
1690bdd1243dSDimitry Andric     if (isSafeToLoadUnconditionally(Value, LI.getType(), LI.getAlign(), DL,
1691bdd1243dSDimitry Andric                                     &LI))
1692bdd1243dSDimitry Andric       Spec.setAsSpeculatable(/*isTrueVal=*/Value == SI.getTrueValue());
1693bdd1243dSDimitry Andric     else if (PreserveCFG)
1694bdd1243dSDimitry Andric       return Spec;
1695bdd1243dSDimitry Andric 
1696bdd1243dSDimitry Andric   return Spec;
1697bdd1243dSDimitry Andric }
1698bdd1243dSDimitry Andric 
16995f757f3fSDimitry Andric std::optional<RewriteableMemOps>
17005f757f3fSDimitry Andric SROA::isSafeSelectToSpeculate(SelectInst &SI, bool PreserveCFG) {
1701bdd1243dSDimitry Andric   RewriteableMemOps Ops;
17020b57cec5SDimitry Andric 
17030b57cec5SDimitry Andric   for (User *U : SI.users()) {
1704bdd1243dSDimitry Andric     if (auto *BC = dyn_cast<BitCastInst>(U); BC && BC->hasOneUse())
1705bdd1243dSDimitry Andric       U = *BC->user_begin();
1706349cc55cSDimitry Andric 
1707bdd1243dSDimitry Andric     if (auto *Store = dyn_cast<StoreInst>(U)) {
1708bdd1243dSDimitry Andric       // Note that atomic stores can be transformed; atomic semantics do not
1709bdd1243dSDimitry Andric       // have any meaning for a local alloca. Stores are not speculatable,
1710bdd1243dSDimitry Andric       // however, so if we can't turn it into a predicated store, we are done.
1711bdd1243dSDimitry Andric       if (Store->isVolatile() || PreserveCFG)
1712bdd1243dSDimitry Andric         return {}; // Give up on this `select`.
1713bdd1243dSDimitry Andric       Ops.emplace_back(Store);
1714bdd1243dSDimitry Andric       continue;
17150b57cec5SDimitry Andric     }
17160b57cec5SDimitry Andric 
1717bdd1243dSDimitry Andric     auto *LI = dyn_cast<LoadInst>(U);
1718bdd1243dSDimitry Andric 
1719bdd1243dSDimitry Andric     // Note that atomic loads can be transformed;
1720bdd1243dSDimitry Andric     // atomic semantics do not have any meaning for a local alloca.
1721bdd1243dSDimitry Andric     if (!LI || LI->isVolatile())
1722bdd1243dSDimitry Andric       return {}; // Give up on this `select`.
1723bdd1243dSDimitry Andric 
1724bdd1243dSDimitry Andric     PossiblySpeculatableLoad Load(LI);
1725bdd1243dSDimitry Andric     if (!LI->isSimple()) {
1726bdd1243dSDimitry Andric       // If the `load` is not simple, we can't speculatively execute it,
1727bdd1243dSDimitry Andric       // but we could handle this via a CFG modification. But can we?
1728bdd1243dSDimitry Andric       if (PreserveCFG)
1729bdd1243dSDimitry Andric         return {}; // Give up on this `select`.
1730bdd1243dSDimitry Andric       Ops.emplace_back(Load);
1731bdd1243dSDimitry Andric       continue;
17320b57cec5SDimitry Andric     }
17330b57cec5SDimitry Andric 
17345f757f3fSDimitry Andric     SelectHandSpeculativity Spec =
1735bdd1243dSDimitry Andric         isSafeLoadOfSelectToSpeculate(*LI, SI, PreserveCFG);
1736bdd1243dSDimitry Andric     if (PreserveCFG && !Spec.areAllSpeculatable())
1737bdd1243dSDimitry Andric       return {}; // Give up on this `select`.
17380b57cec5SDimitry Andric 
1739bdd1243dSDimitry Andric     Load.setInt(Spec);
1740bdd1243dSDimitry Andric     Ops.emplace_back(Load);
1741bdd1243dSDimitry Andric   }
1742bdd1243dSDimitry Andric 
1743bdd1243dSDimitry Andric   return Ops;
1744bdd1243dSDimitry Andric }
1745bdd1243dSDimitry Andric 
1746bdd1243dSDimitry Andric static void speculateSelectInstLoads(SelectInst &SI, LoadInst &LI,
1747bdd1243dSDimitry Andric                                      IRBuilderTy &IRB) {
1748bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    original load: " << SI << "\n");
1749bdd1243dSDimitry Andric 
17500b57cec5SDimitry Andric   Value *TV = SI.getTrueValue();
17510b57cec5SDimitry Andric   Value *FV = SI.getFalseValue();
1752bdd1243dSDimitry Andric   // Replace the given load of the select with a select of two loads.
1753bdd1243dSDimitry Andric 
1754bdd1243dSDimitry Andric   assert(LI.isSimple() && "We only speculate simple loads");
1755bdd1243dSDimitry Andric 
1756bdd1243dSDimitry Andric   IRB.SetInsertPoint(&LI);
1757bdd1243dSDimitry Andric 
1758bdd1243dSDimitry Andric   LoadInst *TL =
1759bdd1243dSDimitry Andric       IRB.CreateAlignedLoad(LI.getType(), TV, LI.getAlign(),
1760bdd1243dSDimitry Andric                             LI.getName() + ".sroa.speculate.load.true");
1761bdd1243dSDimitry Andric   LoadInst *FL =
1762bdd1243dSDimitry Andric       IRB.CreateAlignedLoad(LI.getType(), FV, LI.getAlign(),
1763bdd1243dSDimitry Andric                             LI.getName() + ".sroa.speculate.load.false");
17640b57cec5SDimitry Andric   NumLoadsSpeculated += 2;
17650b57cec5SDimitry Andric 
17660b57cec5SDimitry Andric   // Transfer alignment and AA info if present.
1767bdd1243dSDimitry Andric   TL->setAlignment(LI.getAlign());
1768bdd1243dSDimitry Andric   FL->setAlignment(LI.getAlign());
17690b57cec5SDimitry Andric 
1770bdd1243dSDimitry Andric   AAMDNodes Tags = LI.getAAMetadata();
17710b57cec5SDimitry Andric   if (Tags) {
17720b57cec5SDimitry Andric     TL->setAAMetadata(Tags);
17730b57cec5SDimitry Andric     FL->setAAMetadata(Tags);
17740b57cec5SDimitry Andric   }
17750b57cec5SDimitry Andric 
17760b57cec5SDimitry Andric   Value *V = IRB.CreateSelect(SI.getCondition(), TL, FL,
1777bdd1243dSDimitry Andric                               LI.getName() + ".sroa.speculated");
17780b57cec5SDimitry Andric 
17790b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "          speculated to: " << *V << "\n");
1780bdd1243dSDimitry Andric   LI.replaceAllUsesWith(V);
17810b57cec5SDimitry Andric }
1782bdd1243dSDimitry Andric 
1783bdd1243dSDimitry Andric template <typename T>
1784bdd1243dSDimitry Andric static void rewriteMemOpOfSelect(SelectInst &SI, T &I,
17855f757f3fSDimitry Andric                                  SelectHandSpeculativity Spec,
1786bdd1243dSDimitry Andric                                  DomTreeUpdater &DTU) {
1787bdd1243dSDimitry Andric   assert((isa<LoadInst>(I) || isa<StoreInst>(I)) && "Only for load and store!");
1788bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    original mem op: " << I << "\n");
1789bdd1243dSDimitry Andric   BasicBlock *Head = I.getParent();
1790bdd1243dSDimitry Andric   Instruction *ThenTerm = nullptr;
1791bdd1243dSDimitry Andric   Instruction *ElseTerm = nullptr;
1792bdd1243dSDimitry Andric   if (Spec.areNoneSpeculatable())
1793bdd1243dSDimitry Andric     SplitBlockAndInsertIfThenElse(SI.getCondition(), &I, &ThenTerm, &ElseTerm,
1794bdd1243dSDimitry Andric                                   SI.getMetadata(LLVMContext::MD_prof), &DTU);
1795bdd1243dSDimitry Andric   else {
1796bdd1243dSDimitry Andric     SplitBlockAndInsertIfThen(SI.getCondition(), &I, /*Unreachable=*/false,
1797bdd1243dSDimitry Andric                               SI.getMetadata(LLVMContext::MD_prof), &DTU,
1798bdd1243dSDimitry Andric                               /*LI=*/nullptr, /*ThenBlock=*/nullptr);
1799bdd1243dSDimitry Andric     if (Spec.isSpeculatable(/*isTrueVal=*/true))
1800bdd1243dSDimitry Andric       cast<BranchInst>(Head->getTerminator())->swapSuccessors();
1801bdd1243dSDimitry Andric   }
1802bdd1243dSDimitry Andric   auto *HeadBI = cast<BranchInst>(Head->getTerminator());
1803bdd1243dSDimitry Andric   Spec = {}; // Do not use `Spec` beyond this point.
1804bdd1243dSDimitry Andric   BasicBlock *Tail = I.getParent();
1805bdd1243dSDimitry Andric   Tail->setName(Head->getName() + ".cont");
1806bdd1243dSDimitry Andric   PHINode *PN;
1807bdd1243dSDimitry Andric   if (isa<LoadInst>(I))
1808*0fca6ea1SDimitry Andric     PN = PHINode::Create(I.getType(), 2, "", I.getIterator());
1809bdd1243dSDimitry Andric   for (BasicBlock *SuccBB : successors(Head)) {
1810bdd1243dSDimitry Andric     bool IsThen = SuccBB == HeadBI->getSuccessor(0);
1811bdd1243dSDimitry Andric     int SuccIdx = IsThen ? 0 : 1;
1812bdd1243dSDimitry Andric     auto *NewMemOpBB = SuccBB == Tail ? Head : SuccBB;
18139e7101a8SDimitry Andric     auto &CondMemOp = cast<T>(*I.clone());
1814bdd1243dSDimitry Andric     if (NewMemOpBB != Head) {
1815bdd1243dSDimitry Andric       NewMemOpBB->setName(Head->getName() + (IsThen ? ".then" : ".else"));
1816bdd1243dSDimitry Andric       if (isa<LoadInst>(I))
1817bdd1243dSDimitry Andric         ++NumLoadsPredicated;
1818bdd1243dSDimitry Andric       else
1819bdd1243dSDimitry Andric         ++NumStoresPredicated;
18209e7101a8SDimitry Andric     } else {
182106c3fb27SDimitry Andric       CondMemOp.dropUBImplyingAttrsAndMetadata();
1822bdd1243dSDimitry Andric       ++NumLoadsSpeculated;
18239e7101a8SDimitry Andric     }
1824bdd1243dSDimitry Andric     CondMemOp.insertBefore(NewMemOpBB->getTerminator());
1825bdd1243dSDimitry Andric     Value *Ptr = SI.getOperand(1 + SuccIdx);
1826bdd1243dSDimitry Andric     CondMemOp.setOperand(I.getPointerOperandIndex(), Ptr);
1827bdd1243dSDimitry Andric     if (isa<LoadInst>(I)) {
1828bdd1243dSDimitry Andric       CondMemOp.setName(I.getName() + (IsThen ? ".then" : ".else") + ".val");
1829bdd1243dSDimitry Andric       PN->addIncoming(&CondMemOp, NewMemOpBB);
1830bdd1243dSDimitry Andric     } else
1831bdd1243dSDimitry Andric       LLVM_DEBUG(dbgs() << "                 to: " << CondMemOp << "\n");
1832bdd1243dSDimitry Andric   }
1833bdd1243dSDimitry Andric   if (isa<LoadInst>(I)) {
1834bdd1243dSDimitry Andric     PN->takeName(&I);
1835bdd1243dSDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *PN << "\n");
1836bdd1243dSDimitry Andric     I.replaceAllUsesWith(PN);
1837bdd1243dSDimitry Andric   }
1838bdd1243dSDimitry Andric }
1839bdd1243dSDimitry Andric 
1840bdd1243dSDimitry Andric static void rewriteMemOpOfSelect(SelectInst &SelInst, Instruction &I,
18415f757f3fSDimitry Andric                                  SelectHandSpeculativity Spec,
1842bdd1243dSDimitry Andric                                  DomTreeUpdater &DTU) {
1843bdd1243dSDimitry Andric   if (auto *LI = dyn_cast<LoadInst>(&I))
1844bdd1243dSDimitry Andric     rewriteMemOpOfSelect(SelInst, *LI, Spec, DTU);
1845bdd1243dSDimitry Andric   else if (auto *SI = dyn_cast<StoreInst>(&I))
1846bdd1243dSDimitry Andric     rewriteMemOpOfSelect(SelInst, *SI, Spec, DTU);
1847bdd1243dSDimitry Andric   else
1848bdd1243dSDimitry Andric     llvm_unreachable_internal("Only for load and store.");
1849bdd1243dSDimitry Andric }
1850bdd1243dSDimitry Andric 
1851bdd1243dSDimitry Andric static bool rewriteSelectInstMemOps(SelectInst &SI,
18525f757f3fSDimitry Andric                                     const RewriteableMemOps &Ops,
1853bdd1243dSDimitry Andric                                     IRBuilderTy &IRB, DomTreeUpdater *DTU) {
1854bdd1243dSDimitry Andric   bool CFGChanged = false;
1855bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "    original select: " << SI << "\n");
1856bdd1243dSDimitry Andric 
1857bdd1243dSDimitry Andric   for (const RewriteableMemOp &Op : Ops) {
18585f757f3fSDimitry Andric     SelectHandSpeculativity Spec;
1859bdd1243dSDimitry Andric     Instruction *I;
1860bdd1243dSDimitry Andric     if (auto *const *US = std::get_if<UnspeculatableStore>(&Op)) {
1861bdd1243dSDimitry Andric       I = *US;
1862bdd1243dSDimitry Andric     } else {
1863bdd1243dSDimitry Andric       auto PSL = std::get<PossiblySpeculatableLoad>(Op);
1864bdd1243dSDimitry Andric       I = PSL.getPointer();
1865bdd1243dSDimitry Andric       Spec = PSL.getInt();
1866bdd1243dSDimitry Andric     }
1867bdd1243dSDimitry Andric     if (Spec.areAllSpeculatable()) {
1868bdd1243dSDimitry Andric       speculateSelectInstLoads(SI, cast<LoadInst>(*I), IRB);
1869bdd1243dSDimitry Andric     } else {
1870bdd1243dSDimitry Andric       assert(DTU && "Should not get here when not allowed to modify the CFG!");
1871bdd1243dSDimitry Andric       rewriteMemOpOfSelect(SI, *I, Spec, *DTU);
1872bdd1243dSDimitry Andric       CFGChanged = true;
1873bdd1243dSDimitry Andric     }
1874bdd1243dSDimitry Andric     I->eraseFromParent();
1875bdd1243dSDimitry Andric   }
1876bdd1243dSDimitry Andric 
1877bdd1243dSDimitry Andric   for (User *U : make_early_inc_range(SI.users()))
1878bdd1243dSDimitry Andric     cast<BitCastInst>(U)->eraseFromParent();
18790b57cec5SDimitry Andric   SI.eraseFromParent();
1880bdd1243dSDimitry Andric   return CFGChanged;
18810b57cec5SDimitry Andric }
18820b57cec5SDimitry Andric 
18830b57cec5SDimitry Andric /// Compute an adjusted pointer from Ptr by Offset bytes where the
18840b57cec5SDimitry Andric /// resulting pointer has PointerTy.
18850b57cec5SDimitry Andric static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
1886e8d8bef9SDimitry Andric                              APInt Offset, Type *PointerTy,
1887e8d8bef9SDimitry Andric                              const Twine &NamePrefix) {
1888349cc55cSDimitry Andric   if (Offset != 0)
18897a6dacacSDimitry Andric     Ptr = IRB.CreateInBoundsPtrAdd(Ptr, IRB.getInt(Offset),
1890349cc55cSDimitry Andric                                    NamePrefix + "sroa_idx");
1891349cc55cSDimitry Andric   return IRB.CreatePointerBitCastOrAddrSpaceCast(Ptr, PointerTy,
1892349cc55cSDimitry Andric                                                  NamePrefix + "sroa_cast");
1893349cc55cSDimitry Andric }
1894349cc55cSDimitry Andric 
18950b57cec5SDimitry Andric /// Compute the adjusted alignment for a load or store from an offset.
18965ffd83dbSDimitry Andric static Align getAdjustedAlignment(Instruction *I, uint64_t Offset) {
18975ffd83dbSDimitry Andric   return commonAlignment(getLoadStoreAlignment(I), Offset);
18980b57cec5SDimitry Andric }
18990b57cec5SDimitry Andric 
19000b57cec5SDimitry Andric /// Test whether we can convert a value from the old to the new type.
19010b57cec5SDimitry Andric ///
19020b57cec5SDimitry Andric /// This predicate should be used to guard calls to convertValue in order to
19030b57cec5SDimitry Andric /// ensure that we only try to convert viable values. The strategy is that we
19040b57cec5SDimitry Andric /// will peel off single element struct and array wrappings to get to an
19050b57cec5SDimitry Andric /// underlying value, and convert that value.
19060b57cec5SDimitry Andric static bool canConvertValue(const DataLayout &DL, Type *OldTy, Type *NewTy) {
19070b57cec5SDimitry Andric   if (OldTy == NewTy)
19080b57cec5SDimitry Andric     return true;
19090b57cec5SDimitry Andric 
19100b57cec5SDimitry Andric   // For integer types, we can't handle any bit-width differences. This would
19110b57cec5SDimitry Andric   // break both vector conversions with extension and introduce endianness
19120b57cec5SDimitry Andric   // issues when in conjunction with loads and stores.
19130b57cec5SDimitry Andric   if (isa<IntegerType>(OldTy) && isa<IntegerType>(NewTy)) {
19140b57cec5SDimitry Andric     assert(cast<IntegerType>(OldTy)->getBitWidth() !=
19150b57cec5SDimitry Andric                cast<IntegerType>(NewTy)->getBitWidth() &&
19160b57cec5SDimitry Andric            "We can't have the same bitwidth for different int types");
19170b57cec5SDimitry Andric     return false;
19180b57cec5SDimitry Andric   }
19190b57cec5SDimitry Andric 
1920bdd1243dSDimitry Andric   if (DL.getTypeSizeInBits(NewTy).getFixedValue() !=
1921bdd1243dSDimitry Andric       DL.getTypeSizeInBits(OldTy).getFixedValue())
19220b57cec5SDimitry Andric     return false;
19230b57cec5SDimitry Andric   if (!NewTy->isSingleValueType() || !OldTy->isSingleValueType())
19240b57cec5SDimitry Andric     return false;
19250b57cec5SDimitry Andric 
19260b57cec5SDimitry Andric   // We can convert pointers to integers and vice-versa. Same for vectors
19270b57cec5SDimitry Andric   // of pointers and integers.
19280b57cec5SDimitry Andric   OldTy = OldTy->getScalarType();
19290b57cec5SDimitry Andric   NewTy = NewTy->getScalarType();
19300b57cec5SDimitry Andric   if (NewTy->isPointerTy() || OldTy->isPointerTy()) {
19310b57cec5SDimitry Andric     if (NewTy->isPointerTy() && OldTy->isPointerTy()) {
19325ffd83dbSDimitry Andric       unsigned OldAS = OldTy->getPointerAddressSpace();
19335ffd83dbSDimitry Andric       unsigned NewAS = NewTy->getPointerAddressSpace();
19345ffd83dbSDimitry Andric       // Convert pointers if they are pointers from the same address space or
19355ffd83dbSDimitry Andric       // different integral (not non-integral) address spaces with the same
19365ffd83dbSDimitry Andric       // pointer size.
19375ffd83dbSDimitry Andric       return OldAS == NewAS ||
19385ffd83dbSDimitry Andric              (!DL.isNonIntegralAddressSpace(OldAS) &&
19395ffd83dbSDimitry Andric               !DL.isNonIntegralAddressSpace(NewAS) &&
19405ffd83dbSDimitry Andric               DL.getPointerSize(OldAS) == DL.getPointerSize(NewAS));
19410b57cec5SDimitry Andric     }
19420b57cec5SDimitry Andric 
19430b57cec5SDimitry Andric     // We can convert integers to integral pointers, but not to non-integral
19440b57cec5SDimitry Andric     // pointers.
19450b57cec5SDimitry Andric     if (OldTy->isIntegerTy())
19460b57cec5SDimitry Andric       return !DL.isNonIntegralPointerType(NewTy);
19470b57cec5SDimitry Andric 
19480b57cec5SDimitry Andric     // We can convert integral pointers to integers, but non-integral pointers
19490b57cec5SDimitry Andric     // need to remain pointers.
19500b57cec5SDimitry Andric     if (!DL.isNonIntegralPointerType(OldTy))
19510b57cec5SDimitry Andric       return NewTy->isIntegerTy();
19520b57cec5SDimitry Andric 
19530b57cec5SDimitry Andric     return false;
19540b57cec5SDimitry Andric   }
19550b57cec5SDimitry Andric 
1956bdd1243dSDimitry Andric   if (OldTy->isTargetExtTy() || NewTy->isTargetExtTy())
1957bdd1243dSDimitry Andric     return false;
1958bdd1243dSDimitry Andric 
19590b57cec5SDimitry Andric   return true;
19600b57cec5SDimitry Andric }
19610b57cec5SDimitry Andric 
19620b57cec5SDimitry Andric /// Generic routine to convert an SSA value to a value of a different
19630b57cec5SDimitry Andric /// type.
19640b57cec5SDimitry Andric ///
19650b57cec5SDimitry Andric /// This will try various different casting techniques, such as bitcasts,
19660b57cec5SDimitry Andric /// inttoptr, and ptrtoint casts. Use the \c canConvertValue predicate to test
19670b57cec5SDimitry Andric /// two types for viability with this routine.
19680b57cec5SDimitry Andric static Value *convertValue(const DataLayout &DL, IRBuilderTy &IRB, Value *V,
19690b57cec5SDimitry Andric                            Type *NewTy) {
19700b57cec5SDimitry Andric   Type *OldTy = V->getType();
19710b57cec5SDimitry Andric   assert(canConvertValue(DL, OldTy, NewTy) && "Value not convertable to type");
19720b57cec5SDimitry Andric 
19730b57cec5SDimitry Andric   if (OldTy == NewTy)
19740b57cec5SDimitry Andric     return V;
19750b57cec5SDimitry Andric 
19760b57cec5SDimitry Andric   assert(!(isa<IntegerType>(OldTy) && isa<IntegerType>(NewTy)) &&
19770b57cec5SDimitry Andric          "Integer types must be the exact same to convert.");
19780b57cec5SDimitry Andric 
19795ffd83dbSDimitry Andric   // See if we need inttoptr for this type pair. May require additional bitcast.
19800b57cec5SDimitry Andric   if (OldTy->isIntOrIntVectorTy() && NewTy->isPtrOrPtrVectorTy()) {
19810b57cec5SDimitry Andric     // Expand <2 x i32> to i8* --> <2 x i32> to i64 to i8*
19820b57cec5SDimitry Andric     // Expand i128 to <2 x i8*> --> i128 to <2 x i64> to <2 x i8*>
19835ffd83dbSDimitry Andric     // Expand <4 x i32> to <2 x i8*> --> <4 x i32> to <2 x i64> to <2 x i8*>
19845ffd83dbSDimitry Andric     // Directly handle i64 to i8*
19850b57cec5SDimitry Andric     return IRB.CreateIntToPtr(IRB.CreateBitCast(V, DL.getIntPtrType(NewTy)),
19860b57cec5SDimitry Andric                               NewTy);
19870b57cec5SDimitry Andric   }
19880b57cec5SDimitry Andric 
19895ffd83dbSDimitry Andric   // See if we need ptrtoint for this type pair. May require additional bitcast.
19900b57cec5SDimitry Andric   if (OldTy->isPtrOrPtrVectorTy() && NewTy->isIntOrIntVectorTy()) {
19910b57cec5SDimitry Andric     // Expand <2 x i8*> to i128 --> <2 x i8*> to <2 x i64> to i128
19920b57cec5SDimitry Andric     // Expand i8* to <2 x i32> --> i8* to i64 to <2 x i32>
19935ffd83dbSDimitry Andric     // Expand <2 x i8*> to <4 x i32> --> <2 x i8*> to <2 x i64> to <4 x i32>
19945ffd83dbSDimitry Andric     // Expand i8* to i64 --> i8* to i64 to i64
19950b57cec5SDimitry Andric     return IRB.CreateBitCast(IRB.CreatePtrToInt(V, DL.getIntPtrType(OldTy)),
19960b57cec5SDimitry Andric                              NewTy);
19975ffd83dbSDimitry Andric   }
19980b57cec5SDimitry Andric 
19995ffd83dbSDimitry Andric   if (OldTy->isPtrOrPtrVectorTy() && NewTy->isPtrOrPtrVectorTy()) {
20005ffd83dbSDimitry Andric     unsigned OldAS = OldTy->getPointerAddressSpace();
20015ffd83dbSDimitry Andric     unsigned NewAS = NewTy->getPointerAddressSpace();
20025ffd83dbSDimitry Andric     // To convert pointers with different address spaces (they are already
20035ffd83dbSDimitry Andric     // checked convertible, i.e. they have the same pointer size), so far we
20045ffd83dbSDimitry Andric     // cannot use `bitcast` (which has restrict on the same address space) or
20055ffd83dbSDimitry Andric     // `addrspacecast` (which is not always no-op casting). Instead, use a pair
20065ffd83dbSDimitry Andric     // of no-op `ptrtoint`/`inttoptr` casts through an integer with the same bit
20075ffd83dbSDimitry Andric     // size.
20085ffd83dbSDimitry Andric     if (OldAS != NewAS) {
20095ffd83dbSDimitry Andric       assert(DL.getPointerSize(OldAS) == DL.getPointerSize(NewAS));
20105ffd83dbSDimitry Andric       return IRB.CreateIntToPtr(IRB.CreatePtrToInt(V, DL.getIntPtrType(OldTy)),
20115ffd83dbSDimitry Andric                                 NewTy);
20125ffd83dbSDimitry Andric     }
20130b57cec5SDimitry Andric   }
20140b57cec5SDimitry Andric 
20150b57cec5SDimitry Andric   return IRB.CreateBitCast(V, NewTy);
20160b57cec5SDimitry Andric }
20170b57cec5SDimitry Andric 
20180b57cec5SDimitry Andric /// Test whether the given slice use can be promoted to a vector.
20190b57cec5SDimitry Andric ///
20200b57cec5SDimitry Andric /// This function is called to test each entry in a partition which is slated
20210b57cec5SDimitry Andric /// for a single slice.
20220b57cec5SDimitry Andric static bool isVectorPromotionViableForSlice(Partition &P, const Slice &S,
20230b57cec5SDimitry Andric                                             VectorType *Ty,
20240b57cec5SDimitry Andric                                             uint64_t ElementSize,
20250b57cec5SDimitry Andric                                             const DataLayout &DL) {
20260b57cec5SDimitry Andric   // First validate the slice offsets.
20270b57cec5SDimitry Andric   uint64_t BeginOffset =
20280b57cec5SDimitry Andric       std::max(S.beginOffset(), P.beginOffset()) - P.beginOffset();
20290b57cec5SDimitry Andric   uint64_t BeginIndex = BeginOffset / ElementSize;
20300b57cec5SDimitry Andric   if (BeginIndex * ElementSize != BeginOffset ||
20315ffd83dbSDimitry Andric       BeginIndex >= cast<FixedVectorType>(Ty)->getNumElements())
20320b57cec5SDimitry Andric     return false;
2033*0fca6ea1SDimitry Andric   uint64_t EndOffset = std::min(S.endOffset(), P.endOffset()) - P.beginOffset();
20340b57cec5SDimitry Andric   uint64_t EndIndex = EndOffset / ElementSize;
20355ffd83dbSDimitry Andric   if (EndIndex * ElementSize != EndOffset ||
20365ffd83dbSDimitry Andric       EndIndex > cast<FixedVectorType>(Ty)->getNumElements())
20370b57cec5SDimitry Andric     return false;
20380b57cec5SDimitry Andric 
20390b57cec5SDimitry Andric   assert(EndIndex > BeginIndex && "Empty vector!");
20400b57cec5SDimitry Andric   uint64_t NumElements = EndIndex - BeginIndex;
20410b57cec5SDimitry Andric   Type *SliceTy = (NumElements == 1)
20420b57cec5SDimitry Andric                       ? Ty->getElementType()
20435ffd83dbSDimitry Andric                       : FixedVectorType::get(Ty->getElementType(), NumElements);
20440b57cec5SDimitry Andric 
20450b57cec5SDimitry Andric   Type *SplitIntTy =
20460b57cec5SDimitry Andric       Type::getIntNTy(Ty->getContext(), NumElements * ElementSize * 8);
20470b57cec5SDimitry Andric 
20480b57cec5SDimitry Andric   Use *U = S.getUse();
20490b57cec5SDimitry Andric 
20500b57cec5SDimitry Andric   if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
20510b57cec5SDimitry Andric     if (MI->isVolatile())
20520b57cec5SDimitry Andric       return false;
20530b57cec5SDimitry Andric     if (!S.isSplittable())
20540b57cec5SDimitry Andric       return false; // Skip any unsplittable intrinsics.
20550b57cec5SDimitry Andric   } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U->getUser())) {
2056e8d8bef9SDimitry Andric     if (!II->isLifetimeStartOrEnd() && !II->isDroppable())
20570b57cec5SDimitry Andric       return false;
20580b57cec5SDimitry Andric   } else if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
20590b57cec5SDimitry Andric     if (LI->isVolatile())
20600b57cec5SDimitry Andric       return false;
20610b57cec5SDimitry Andric     Type *LTy = LI->getType();
2062349cc55cSDimitry Andric     // Disable vector promotion when there are loads or stores of an FCA.
2063349cc55cSDimitry Andric     if (LTy->isStructTy())
2064349cc55cSDimitry Andric       return false;
20650b57cec5SDimitry Andric     if (P.beginOffset() > S.beginOffset() || P.endOffset() < S.endOffset()) {
20660b57cec5SDimitry Andric       assert(LTy->isIntegerTy());
20670b57cec5SDimitry Andric       LTy = SplitIntTy;
20680b57cec5SDimitry Andric     }
20690b57cec5SDimitry Andric     if (!canConvertValue(DL, SliceTy, LTy))
20700b57cec5SDimitry Andric       return false;
20710b57cec5SDimitry Andric   } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
20720b57cec5SDimitry Andric     if (SI->isVolatile())
20730b57cec5SDimitry Andric       return false;
20740b57cec5SDimitry Andric     Type *STy = SI->getValueOperand()->getType();
2075349cc55cSDimitry Andric     // Disable vector promotion when there are loads or stores of an FCA.
2076349cc55cSDimitry Andric     if (STy->isStructTy())
2077349cc55cSDimitry Andric       return false;
20780b57cec5SDimitry Andric     if (P.beginOffset() > S.beginOffset() || P.endOffset() < S.endOffset()) {
20790b57cec5SDimitry Andric       assert(STy->isIntegerTy());
20800b57cec5SDimitry Andric       STy = SplitIntTy;
20810b57cec5SDimitry Andric     }
20820b57cec5SDimitry Andric     if (!canConvertValue(DL, STy, SliceTy))
20830b57cec5SDimitry Andric       return false;
20840b57cec5SDimitry Andric   } else {
20850b57cec5SDimitry Andric     return false;
20860b57cec5SDimitry Andric   }
20870b57cec5SDimitry Andric 
20880b57cec5SDimitry Andric   return true;
20890b57cec5SDimitry Andric }
20900b57cec5SDimitry Andric 
2091bdd1243dSDimitry Andric /// Test whether a vector type is viable for promotion.
2092bdd1243dSDimitry Andric ///
20937a6dacacSDimitry Andric /// This implements the necessary checking for \c checkVectorTypesForPromotion
20947a6dacacSDimitry Andric /// (and thus isVectorPromotionViable) over all slices of the alloca for the
20957a6dacacSDimitry Andric /// given VectorType.
2096bdd1243dSDimitry Andric static bool checkVectorTypeForPromotion(Partition &P, VectorType *VTy,
2097bdd1243dSDimitry Andric                                         const DataLayout &DL) {
2098bdd1243dSDimitry Andric   uint64_t ElementSize =
2099bdd1243dSDimitry Andric       DL.getTypeSizeInBits(VTy->getElementType()).getFixedValue();
2100bdd1243dSDimitry Andric 
2101bdd1243dSDimitry Andric   // While the definition of LLVM vectors is bitpacked, we don't support sizes
2102bdd1243dSDimitry Andric   // that aren't byte sized.
2103bdd1243dSDimitry Andric   if (ElementSize % 8)
2104bdd1243dSDimitry Andric     return false;
2105bdd1243dSDimitry Andric   assert((DL.getTypeSizeInBits(VTy).getFixedValue() % 8) == 0 &&
2106bdd1243dSDimitry Andric          "vector size not a multiple of element size?");
2107bdd1243dSDimitry Andric   ElementSize /= 8;
2108bdd1243dSDimitry Andric 
2109bdd1243dSDimitry Andric   for (const Slice &S : P)
2110bdd1243dSDimitry Andric     if (!isVectorPromotionViableForSlice(P, S, VTy, ElementSize, DL))
2111bdd1243dSDimitry Andric       return false;
2112bdd1243dSDimitry Andric 
2113bdd1243dSDimitry Andric   for (const Slice *S : P.splitSliceTails())
2114bdd1243dSDimitry Andric     if (!isVectorPromotionViableForSlice(P, *S, VTy, ElementSize, DL))
2115bdd1243dSDimitry Andric       return false;
2116bdd1243dSDimitry Andric 
2117bdd1243dSDimitry Andric   return true;
2118bdd1243dSDimitry Andric }
2119bdd1243dSDimitry Andric 
21207a6dacacSDimitry Andric /// Test whether any vector type in \p CandidateTys is viable for promotion.
21210b57cec5SDimitry Andric ///
21227a6dacacSDimitry Andric /// This implements the necessary checking for \c isVectorPromotionViable over
21237a6dacacSDimitry Andric /// all slices of the alloca for the given VectorType.
21247a6dacacSDimitry Andric static VectorType *
21257a6dacacSDimitry Andric checkVectorTypesForPromotion(Partition &P, const DataLayout &DL,
21267a6dacacSDimitry Andric                              SmallVectorImpl<VectorType *> &CandidateTys,
21277a6dacacSDimitry Andric                              bool HaveCommonEltTy, Type *CommonEltTy,
21287a6dacacSDimitry Andric                              bool HaveVecPtrTy, bool HaveCommonVecPtrTy,
21297a6dacacSDimitry Andric                              VectorType *CommonVecPtrTy) {
21300b57cec5SDimitry Andric   // If we didn't find a vector type, nothing to do here.
21310b57cec5SDimitry Andric   if (CandidateTys.empty())
21320b57cec5SDimitry Andric     return nullptr;
21330b57cec5SDimitry Andric 
2134bdd1243dSDimitry Andric   // Pointer-ness is sticky, if we had a vector-of-pointers candidate type,
2135bdd1243dSDimitry Andric   // then we should choose it, not some other alternative.
2136bdd1243dSDimitry Andric   // But, we can't perform a no-op pointer address space change via bitcast,
2137bdd1243dSDimitry Andric   // so if we didn't have a common pointer element type, bail.
2138bdd1243dSDimitry Andric   if (HaveVecPtrTy && !HaveCommonVecPtrTy)
21390b57cec5SDimitry Andric     return nullptr;
21400b57cec5SDimitry Andric 
2141bdd1243dSDimitry Andric   // Try to pick the "best" element type out of the choices.
2142bdd1243dSDimitry Andric   if (!HaveCommonEltTy && HaveVecPtrTy) {
2143bdd1243dSDimitry Andric     // If there was a pointer element type, there's really only one choice.
2144bdd1243dSDimitry Andric     CandidateTys.clear();
2145bdd1243dSDimitry Andric     CandidateTys.push_back(CommonVecPtrTy);
2146bdd1243dSDimitry Andric   } else if (!HaveCommonEltTy && !HaveVecPtrTy) {
2147bdd1243dSDimitry Andric     // Integer-ify vector types.
2148bdd1243dSDimitry Andric     for (VectorType *&VTy : CandidateTys) {
2149bdd1243dSDimitry Andric       if (!VTy->getElementType()->isIntegerTy())
2150bdd1243dSDimitry Andric         VTy = cast<VectorType>(VTy->getWithNewType(IntegerType::getIntNTy(
2151bdd1243dSDimitry Andric             VTy->getContext(), VTy->getScalarSizeInBits())));
2152bdd1243dSDimitry Andric     }
2153bdd1243dSDimitry Andric 
21540b57cec5SDimitry Andric     // Rank the remaining candidate vector types. This is easy because we know
21550b57cec5SDimitry Andric     // they're all integer vectors. We sort by ascending number of elements.
215606c3fb27SDimitry Andric     auto RankVectorTypesComp = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
21570b57cec5SDimitry Andric       (void)DL;
2158bdd1243dSDimitry Andric       assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
2159bdd1243dSDimitry Andric                  DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
21600b57cec5SDimitry Andric              "Cannot have vector types of different sizes!");
21610b57cec5SDimitry Andric       assert(RHSTy->getElementType()->isIntegerTy() &&
21620b57cec5SDimitry Andric              "All non-integer types eliminated!");
21630b57cec5SDimitry Andric       assert(LHSTy->getElementType()->isIntegerTy() &&
21640b57cec5SDimitry Andric              "All non-integer types eliminated!");
21655ffd83dbSDimitry Andric       return cast<FixedVectorType>(RHSTy)->getNumElements() <
21665ffd83dbSDimitry Andric              cast<FixedVectorType>(LHSTy)->getNumElements();
21670b57cec5SDimitry Andric     };
216806c3fb27SDimitry Andric     auto RankVectorTypesEq = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
216906c3fb27SDimitry Andric       (void)DL;
217006c3fb27SDimitry Andric       assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
217106c3fb27SDimitry Andric                  DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
217206c3fb27SDimitry Andric              "Cannot have vector types of different sizes!");
217306c3fb27SDimitry Andric       assert(RHSTy->getElementType()->isIntegerTy() &&
217406c3fb27SDimitry Andric              "All non-integer types eliminated!");
217506c3fb27SDimitry Andric       assert(LHSTy->getElementType()->isIntegerTy() &&
217606c3fb27SDimitry Andric              "All non-integer types eliminated!");
217706c3fb27SDimitry Andric       return cast<FixedVectorType>(RHSTy)->getNumElements() ==
217806c3fb27SDimitry Andric              cast<FixedVectorType>(LHSTy)->getNumElements();
217906c3fb27SDimitry Andric     };
218006c3fb27SDimitry Andric     llvm::sort(CandidateTys, RankVectorTypesComp);
2181*0fca6ea1SDimitry Andric     CandidateTys.erase(llvm::unique(CandidateTys, RankVectorTypesEq),
21820b57cec5SDimitry Andric                        CandidateTys.end());
21830b57cec5SDimitry Andric   } else {
21840b57cec5SDimitry Andric // The only way to have the same element type in every vector type is to
21850b57cec5SDimitry Andric // have the same vector type. Check that and remove all but one.
21860b57cec5SDimitry Andric #ifndef NDEBUG
21870b57cec5SDimitry Andric     for (VectorType *VTy : CandidateTys) {
21880b57cec5SDimitry Andric       assert(VTy->getElementType() == CommonEltTy &&
21890b57cec5SDimitry Andric              "Unaccounted for element type!");
21900b57cec5SDimitry Andric       assert(VTy == CandidateTys[0] &&
21910b57cec5SDimitry Andric              "Different vector types with the same element type!");
21920b57cec5SDimitry Andric     }
21930b57cec5SDimitry Andric #endif
21940b57cec5SDimitry Andric     CandidateTys.resize(1);
21950b57cec5SDimitry Andric   }
21960b57cec5SDimitry Andric 
2197bdd1243dSDimitry Andric   // FIXME: hack. Do we have a named constant for this?
2198bdd1243dSDimitry Andric   // SDAG SDNode can't have more than 65535 operands.
2199bdd1243dSDimitry Andric   llvm::erase_if(CandidateTys, [](VectorType *VTy) {
2200bdd1243dSDimitry Andric     return cast<FixedVectorType>(VTy)->getNumElements() >
2201bdd1243dSDimitry Andric            std::numeric_limits<unsigned short>::max();
2202bdd1243dSDimitry Andric   });
22030b57cec5SDimitry Andric 
22040b57cec5SDimitry Andric   for (VectorType *VTy : CandidateTys)
2205bdd1243dSDimitry Andric     if (checkVectorTypeForPromotion(P, VTy, DL))
22060b57cec5SDimitry Andric       return VTy;
22070b57cec5SDimitry Andric 
22080b57cec5SDimitry Andric   return nullptr;
22090b57cec5SDimitry Andric }
22100b57cec5SDimitry Andric 
2211439352acSDimitry Andric static VectorType *createAndCheckVectorTypesForPromotion(
2212439352acSDimitry Andric     SetVector<Type *> &OtherTys, ArrayRef<VectorType *> CandidateTysCopy,
2213439352acSDimitry Andric     function_ref<void(Type *)> CheckCandidateType, Partition &P,
2214439352acSDimitry Andric     const DataLayout &DL, SmallVectorImpl<VectorType *> &CandidateTys,
2215439352acSDimitry Andric     bool &HaveCommonEltTy, Type *&CommonEltTy, bool &HaveVecPtrTy,
2216439352acSDimitry Andric     bool &HaveCommonVecPtrTy, VectorType *&CommonVecPtrTy) {
2217439352acSDimitry Andric   [[maybe_unused]] VectorType *OriginalElt =
2218439352acSDimitry Andric       CandidateTysCopy.size() ? CandidateTysCopy[0] : nullptr;
2219439352acSDimitry Andric   // Consider additional vector types where the element type size is a
2220439352acSDimitry Andric   // multiple of load/store element size.
2221439352acSDimitry Andric   for (Type *Ty : OtherTys) {
2222439352acSDimitry Andric     if (!VectorType::isValidElementType(Ty))
2223439352acSDimitry Andric       continue;
2224439352acSDimitry Andric     unsigned TypeSize = DL.getTypeSizeInBits(Ty).getFixedValue();
2225439352acSDimitry Andric     // Make a copy of CandidateTys and iterate through it, because we
2226439352acSDimitry Andric     // might append to CandidateTys in the loop.
2227439352acSDimitry Andric     for (VectorType *const VTy : CandidateTysCopy) {
2228439352acSDimitry Andric       // The elements in the copy should remain invariant throughout the loop
2229439352acSDimitry Andric       assert(CandidateTysCopy[0] == OriginalElt && "Different Element");
2230439352acSDimitry Andric       unsigned VectorSize = DL.getTypeSizeInBits(VTy).getFixedValue();
2231439352acSDimitry Andric       unsigned ElementSize =
2232439352acSDimitry Andric           DL.getTypeSizeInBits(VTy->getElementType()).getFixedValue();
2233439352acSDimitry Andric       if (TypeSize != VectorSize && TypeSize != ElementSize &&
2234439352acSDimitry Andric           VectorSize % TypeSize == 0) {
2235439352acSDimitry Andric         VectorType *NewVTy = VectorType::get(Ty, VectorSize / TypeSize, false);
2236439352acSDimitry Andric         CheckCandidateType(NewVTy);
2237439352acSDimitry Andric       }
2238439352acSDimitry Andric     }
2239439352acSDimitry Andric   }
2240439352acSDimitry Andric 
2241439352acSDimitry Andric   return checkVectorTypesForPromotion(P, DL, CandidateTys, HaveCommonEltTy,
2242439352acSDimitry Andric                                       CommonEltTy, HaveVecPtrTy,
2243439352acSDimitry Andric                                       HaveCommonVecPtrTy, CommonVecPtrTy);
2244439352acSDimitry Andric }
2245439352acSDimitry Andric 
22467a6dacacSDimitry Andric /// Test whether the given alloca partitioning and range of slices can be
22477a6dacacSDimitry Andric /// promoted to a vector.
22487a6dacacSDimitry Andric ///
22497a6dacacSDimitry Andric /// This is a quick test to check whether we can rewrite a particular alloca
22507a6dacacSDimitry Andric /// partition (and its newly formed alloca) into a vector alloca with only
22517a6dacacSDimitry Andric /// whole-vector loads and stores such that it could be promoted to a vector
22527a6dacacSDimitry Andric /// SSA value. We only can ensure this for a limited set of operations, and we
22537a6dacacSDimitry Andric /// don't want to do the rewrites unless we are confident that the result will
22547a6dacacSDimitry Andric /// be promotable, so we have an early test here.
22557a6dacacSDimitry Andric static VectorType *isVectorPromotionViable(Partition &P, const DataLayout &DL) {
22567a6dacacSDimitry Andric   // Collect the candidate types for vector-based promotion. Also track whether
22577a6dacacSDimitry Andric   // we have different element types.
22587a6dacacSDimitry Andric   SmallVector<VectorType *, 4> CandidateTys;
22597a6dacacSDimitry Andric   SetVector<Type *> LoadStoreTys;
2260439352acSDimitry Andric   SetVector<Type *> DeferredTys;
22617a6dacacSDimitry Andric   Type *CommonEltTy = nullptr;
22627a6dacacSDimitry Andric   VectorType *CommonVecPtrTy = nullptr;
22637a6dacacSDimitry Andric   bool HaveVecPtrTy = false;
22647a6dacacSDimitry Andric   bool HaveCommonEltTy = true;
22657a6dacacSDimitry Andric   bool HaveCommonVecPtrTy = true;
22667a6dacacSDimitry Andric   auto CheckCandidateType = [&](Type *Ty) {
22677a6dacacSDimitry Andric     if (auto *VTy = dyn_cast<VectorType>(Ty)) {
22687a6dacacSDimitry Andric       // Return if bitcast to vectors is different for total size in bits.
22697a6dacacSDimitry Andric       if (!CandidateTys.empty()) {
22707a6dacacSDimitry Andric         VectorType *V = CandidateTys[0];
22717a6dacacSDimitry Andric         if (DL.getTypeSizeInBits(VTy).getFixedValue() !=
22727a6dacacSDimitry Andric             DL.getTypeSizeInBits(V).getFixedValue()) {
22737a6dacacSDimitry Andric           CandidateTys.clear();
22747a6dacacSDimitry Andric           return;
22757a6dacacSDimitry Andric         }
22767a6dacacSDimitry Andric       }
22777a6dacacSDimitry Andric       CandidateTys.push_back(VTy);
22787a6dacacSDimitry Andric       Type *EltTy = VTy->getElementType();
22797a6dacacSDimitry Andric 
22807a6dacacSDimitry Andric       if (!CommonEltTy)
22817a6dacacSDimitry Andric         CommonEltTy = EltTy;
22827a6dacacSDimitry Andric       else if (CommonEltTy != EltTy)
22837a6dacacSDimitry Andric         HaveCommonEltTy = false;
22847a6dacacSDimitry Andric 
22857a6dacacSDimitry Andric       if (EltTy->isPointerTy()) {
22867a6dacacSDimitry Andric         HaveVecPtrTy = true;
22877a6dacacSDimitry Andric         if (!CommonVecPtrTy)
22887a6dacacSDimitry Andric           CommonVecPtrTy = VTy;
22897a6dacacSDimitry Andric         else if (CommonVecPtrTy != VTy)
22907a6dacacSDimitry Andric           HaveCommonVecPtrTy = false;
22917a6dacacSDimitry Andric       }
22927a6dacacSDimitry Andric     }
22937a6dacacSDimitry Andric   };
22947a6dacacSDimitry Andric 
22957a6dacacSDimitry Andric   // Put load and store types into a set for de-duplication.
22967a6dacacSDimitry Andric   for (const Slice &S : P) {
22977a6dacacSDimitry Andric     Type *Ty;
22987a6dacacSDimitry Andric     if (auto *LI = dyn_cast<LoadInst>(S.getUse()->getUser()))
22997a6dacacSDimitry Andric       Ty = LI->getType();
23007a6dacacSDimitry Andric     else if (auto *SI = dyn_cast<StoreInst>(S.getUse()->getUser()))
23017a6dacacSDimitry Andric       Ty = SI->getValueOperand()->getType();
23027a6dacacSDimitry Andric     else
23037a6dacacSDimitry Andric       continue;
2304439352acSDimitry Andric 
2305439352acSDimitry Andric     auto CandTy = Ty->getScalarType();
2306439352acSDimitry Andric     if (CandTy->isPointerTy() && (S.beginOffset() != P.beginOffset() ||
2307439352acSDimitry Andric                                   S.endOffset() != P.endOffset())) {
2308439352acSDimitry Andric       DeferredTys.insert(Ty);
2309439352acSDimitry Andric       continue;
2310439352acSDimitry Andric     }
2311439352acSDimitry Andric 
23127a6dacacSDimitry Andric     LoadStoreTys.insert(Ty);
23137a6dacacSDimitry Andric     // Consider any loads or stores that are the exact size of the slice.
23147a6dacacSDimitry Andric     if (S.beginOffset() == P.beginOffset() && S.endOffset() == P.endOffset())
23157a6dacacSDimitry Andric       CheckCandidateType(Ty);
23167a6dacacSDimitry Andric   }
23177a6dacacSDimitry Andric 
2318439352acSDimitry Andric   SmallVector<VectorType *, 4> CandidateTysCopy = CandidateTys;
2319439352acSDimitry Andric   if (auto *VTy = createAndCheckVectorTypesForPromotion(
2320439352acSDimitry Andric           LoadStoreTys, CandidateTysCopy, CheckCandidateType, P, DL,
2321439352acSDimitry Andric           CandidateTys, HaveCommonEltTy, CommonEltTy, HaveVecPtrTy,
23227a6dacacSDimitry Andric           HaveCommonVecPtrTy, CommonVecPtrTy))
23237a6dacacSDimitry Andric     return VTy;
23247a6dacacSDimitry Andric 
23257a6dacacSDimitry Andric   CandidateTys.clear();
2326439352acSDimitry Andric   return createAndCheckVectorTypesForPromotion(
2327439352acSDimitry Andric       DeferredTys, CandidateTysCopy, CheckCandidateType, P, DL, CandidateTys,
2328439352acSDimitry Andric       HaveCommonEltTy, CommonEltTy, HaveVecPtrTy, HaveCommonVecPtrTy,
2329439352acSDimitry Andric       CommonVecPtrTy);
23307a6dacacSDimitry Andric }
23317a6dacacSDimitry Andric 
23320b57cec5SDimitry Andric /// Test whether a slice of an alloca is valid for integer widening.
23330b57cec5SDimitry Andric ///
23340b57cec5SDimitry Andric /// This implements the necessary checking for the \c isIntegerWideningViable
23350b57cec5SDimitry Andric /// test below on a single slice of the alloca.
23360b57cec5SDimitry Andric static bool isIntegerWideningViableForSlice(const Slice &S,
23370b57cec5SDimitry Andric                                             uint64_t AllocBeginOffset,
23380b57cec5SDimitry Andric                                             Type *AllocaTy,
23390b57cec5SDimitry Andric                                             const DataLayout &DL,
23400b57cec5SDimitry Andric                                             bool &WholeAllocaOp) {
2341bdd1243dSDimitry Andric   uint64_t Size = DL.getTypeStoreSize(AllocaTy).getFixedValue();
23420b57cec5SDimitry Andric 
23430b57cec5SDimitry Andric   uint64_t RelBegin = S.beginOffset() - AllocBeginOffset;
23440b57cec5SDimitry Andric   uint64_t RelEnd = S.endOffset() - AllocBeginOffset;
23450b57cec5SDimitry Andric 
234681ad6265SDimitry Andric   Use *U = S.getUse();
234781ad6265SDimitry Andric 
234881ad6265SDimitry Andric   // Lifetime intrinsics operate over the whole alloca whose sizes are usually
234981ad6265SDimitry Andric   // larger than other load/store slices (RelEnd > Size). But lifetime are
235081ad6265SDimitry Andric   // always promotable and should not impact other slices' promotability of the
235181ad6265SDimitry Andric   // partition.
235281ad6265SDimitry Andric   if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U->getUser())) {
235381ad6265SDimitry Andric     if (II->isLifetimeStartOrEnd() || II->isDroppable())
235481ad6265SDimitry Andric       return true;
235581ad6265SDimitry Andric   }
235681ad6265SDimitry Andric 
23570b57cec5SDimitry Andric   // We can't reasonably handle cases where the load or store extends past
23580b57cec5SDimitry Andric   // the end of the alloca's type and into its padding.
23590b57cec5SDimitry Andric   if (RelEnd > Size)
23600b57cec5SDimitry Andric     return false;
23610b57cec5SDimitry Andric 
23620b57cec5SDimitry Andric   if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
23630b57cec5SDimitry Andric     if (LI->isVolatile())
23640b57cec5SDimitry Andric       return false;
23650b57cec5SDimitry Andric     // We can't handle loads that extend past the allocated memory.
2366bdd1243dSDimitry Andric     if (DL.getTypeStoreSize(LI->getType()).getFixedValue() > Size)
23670b57cec5SDimitry Andric       return false;
23680b57cec5SDimitry Andric     // So far, AllocaSliceRewriter does not support widening split slice tails
23690b57cec5SDimitry Andric     // in rewriteIntegerLoad.
23700b57cec5SDimitry Andric     if (S.beginOffset() < AllocBeginOffset)
23710b57cec5SDimitry Andric       return false;
23720b57cec5SDimitry Andric     // Note that we don't count vector loads or stores as whole-alloca
23730b57cec5SDimitry Andric     // operations which enable integer widening because we would prefer to use
23740b57cec5SDimitry Andric     // vector widening instead.
23750b57cec5SDimitry Andric     if (!isa<VectorType>(LI->getType()) && RelBegin == 0 && RelEnd == Size)
23760b57cec5SDimitry Andric       WholeAllocaOp = true;
23770b57cec5SDimitry Andric     if (IntegerType *ITy = dyn_cast<IntegerType>(LI->getType())) {
2378bdd1243dSDimitry Andric       if (ITy->getBitWidth() < DL.getTypeStoreSizeInBits(ITy).getFixedValue())
23790b57cec5SDimitry Andric         return false;
23800b57cec5SDimitry Andric     } else if (RelBegin != 0 || RelEnd != Size ||
23810b57cec5SDimitry Andric                !canConvertValue(DL, AllocaTy, LI->getType())) {
23820b57cec5SDimitry Andric       // Non-integer loads need to be convertible from the alloca type so that
23830b57cec5SDimitry Andric       // they are promotable.
23840b57cec5SDimitry Andric       return false;
23850b57cec5SDimitry Andric     }
23860b57cec5SDimitry Andric   } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
23870b57cec5SDimitry Andric     Type *ValueTy = SI->getValueOperand()->getType();
23880b57cec5SDimitry Andric     if (SI->isVolatile())
23890b57cec5SDimitry Andric       return false;
23900b57cec5SDimitry Andric     // We can't handle stores that extend past the allocated memory.
2391bdd1243dSDimitry Andric     if (DL.getTypeStoreSize(ValueTy).getFixedValue() > Size)
23920b57cec5SDimitry Andric       return false;
23930b57cec5SDimitry Andric     // So far, AllocaSliceRewriter does not support widening split slice tails
23940b57cec5SDimitry Andric     // in rewriteIntegerStore.
23950b57cec5SDimitry Andric     if (S.beginOffset() < AllocBeginOffset)
23960b57cec5SDimitry Andric       return false;
23970b57cec5SDimitry Andric     // Note that we don't count vector loads or stores as whole-alloca
23980b57cec5SDimitry Andric     // operations which enable integer widening because we would prefer to use
23990b57cec5SDimitry Andric     // vector widening instead.
24000b57cec5SDimitry Andric     if (!isa<VectorType>(ValueTy) && RelBegin == 0 && RelEnd == Size)
24010b57cec5SDimitry Andric       WholeAllocaOp = true;
24020b57cec5SDimitry Andric     if (IntegerType *ITy = dyn_cast<IntegerType>(ValueTy)) {
2403bdd1243dSDimitry Andric       if (ITy->getBitWidth() < DL.getTypeStoreSizeInBits(ITy).getFixedValue())
24040b57cec5SDimitry Andric         return false;
24050b57cec5SDimitry Andric     } else if (RelBegin != 0 || RelEnd != Size ||
24060b57cec5SDimitry Andric                !canConvertValue(DL, ValueTy, AllocaTy)) {
24070b57cec5SDimitry Andric       // Non-integer stores need to be convertible to the alloca type so that
24080b57cec5SDimitry Andric       // they are promotable.
24090b57cec5SDimitry Andric       return false;
24100b57cec5SDimitry Andric     }
24110b57cec5SDimitry Andric   } else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
24120b57cec5SDimitry Andric     if (MI->isVolatile() || !isa<Constant>(MI->getLength()))
24130b57cec5SDimitry Andric       return false;
24140b57cec5SDimitry Andric     if (!S.isSplittable())
24150b57cec5SDimitry Andric       return false; // Skip any unsplittable intrinsics.
24160b57cec5SDimitry Andric   } else {
24170b57cec5SDimitry Andric     return false;
24180b57cec5SDimitry Andric   }
24190b57cec5SDimitry Andric 
24200b57cec5SDimitry Andric   return true;
24210b57cec5SDimitry Andric }
24220b57cec5SDimitry Andric 
24230b57cec5SDimitry Andric /// Test whether the given alloca partition's integer operations can be
24240b57cec5SDimitry Andric /// widened to promotable ones.
24250b57cec5SDimitry Andric ///
24260b57cec5SDimitry Andric /// This is a quick test to check whether we can rewrite the integer loads and
24270b57cec5SDimitry Andric /// stores to a particular alloca into wider loads and stores and be able to
24280b57cec5SDimitry Andric /// promote the resulting alloca.
24290b57cec5SDimitry Andric static bool isIntegerWideningViable(Partition &P, Type *AllocaTy,
24300b57cec5SDimitry Andric                                     const DataLayout &DL) {
2431bdd1243dSDimitry Andric   uint64_t SizeInBits = DL.getTypeSizeInBits(AllocaTy).getFixedValue();
24320b57cec5SDimitry Andric   // Don't create integer types larger than the maximum bitwidth.
24330b57cec5SDimitry Andric   if (SizeInBits > IntegerType::MAX_INT_BITS)
24340b57cec5SDimitry Andric     return false;
24350b57cec5SDimitry Andric 
24360b57cec5SDimitry Andric   // Don't try to handle allocas with bit-padding.
2437bdd1243dSDimitry Andric   if (SizeInBits != DL.getTypeStoreSizeInBits(AllocaTy).getFixedValue())
24380b57cec5SDimitry Andric     return false;
24390b57cec5SDimitry Andric 
24400b57cec5SDimitry Andric   // We need to ensure that an integer type with the appropriate bitwidth can
24410b57cec5SDimitry Andric   // be converted to the alloca type, whatever that is. We don't want to force
24420b57cec5SDimitry Andric   // the alloca itself to have an integer type if there is a more suitable one.
24430b57cec5SDimitry Andric   Type *IntTy = Type::getIntNTy(AllocaTy->getContext(), SizeInBits);
24440b57cec5SDimitry Andric   if (!canConvertValue(DL, AllocaTy, IntTy) ||
24450b57cec5SDimitry Andric       !canConvertValue(DL, IntTy, AllocaTy))
24460b57cec5SDimitry Andric     return false;
24470b57cec5SDimitry Andric 
24480b57cec5SDimitry Andric   // While examining uses, we ensure that the alloca has a covering load or
24490b57cec5SDimitry Andric   // store. We don't want to widen the integer operations only to fail to
24500b57cec5SDimitry Andric   // promote due to some other unsplittable entry (which we may make splittable
24510b57cec5SDimitry Andric   // later). However, if there are only splittable uses, go ahead and assume
24520b57cec5SDimitry Andric   // that we cover the alloca.
24530b57cec5SDimitry Andric   // FIXME: We shouldn't consider split slices that happen to start in the
24540b57cec5SDimitry Andric   // partition here...
2455e8d8bef9SDimitry Andric   bool WholeAllocaOp = P.empty() && DL.isLegalInteger(SizeInBits);
24560b57cec5SDimitry Andric 
24570b57cec5SDimitry Andric   for (const Slice &S : P)
24580b57cec5SDimitry Andric     if (!isIntegerWideningViableForSlice(S, P.beginOffset(), AllocaTy, DL,
24590b57cec5SDimitry Andric                                          WholeAllocaOp))
24600b57cec5SDimitry Andric       return false;
24610b57cec5SDimitry Andric 
24620b57cec5SDimitry Andric   for (const Slice *S : P.splitSliceTails())
24630b57cec5SDimitry Andric     if (!isIntegerWideningViableForSlice(*S, P.beginOffset(), AllocaTy, DL,
24640b57cec5SDimitry Andric                                          WholeAllocaOp))
24650b57cec5SDimitry Andric       return false;
24660b57cec5SDimitry Andric 
24670b57cec5SDimitry Andric   return WholeAllocaOp;
24680b57cec5SDimitry Andric }
24690b57cec5SDimitry Andric 
24700b57cec5SDimitry Andric static Value *extractInteger(const DataLayout &DL, IRBuilderTy &IRB, Value *V,
24710b57cec5SDimitry Andric                              IntegerType *Ty, uint64_t Offset,
24720b57cec5SDimitry Andric                              const Twine &Name) {
24730b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "       start: " << *V << "\n");
24740b57cec5SDimitry Andric   IntegerType *IntTy = cast<IntegerType>(V->getType());
2475bdd1243dSDimitry Andric   assert(DL.getTypeStoreSize(Ty).getFixedValue() + Offset <=
2476bdd1243dSDimitry Andric              DL.getTypeStoreSize(IntTy).getFixedValue() &&
24770b57cec5SDimitry Andric          "Element extends past full value");
24780b57cec5SDimitry Andric   uint64_t ShAmt = 8 * Offset;
24790b57cec5SDimitry Andric   if (DL.isBigEndian())
2480bdd1243dSDimitry Andric     ShAmt = 8 * (DL.getTypeStoreSize(IntTy).getFixedValue() -
2481bdd1243dSDimitry Andric                  DL.getTypeStoreSize(Ty).getFixedValue() - Offset);
24820b57cec5SDimitry Andric   if (ShAmt) {
24830b57cec5SDimitry Andric     V = IRB.CreateLShr(V, ShAmt, Name + ".shift");
24840b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "     shifted: " << *V << "\n");
24850b57cec5SDimitry Andric   }
24860b57cec5SDimitry Andric   assert(Ty->getBitWidth() <= IntTy->getBitWidth() &&
24870b57cec5SDimitry Andric          "Cannot extract to a larger integer!");
24880b57cec5SDimitry Andric   if (Ty != IntTy) {
24890b57cec5SDimitry Andric     V = IRB.CreateTrunc(V, Ty, Name + ".trunc");
24900b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "     trunced: " << *V << "\n");
24910b57cec5SDimitry Andric   }
24920b57cec5SDimitry Andric   return V;
24930b57cec5SDimitry Andric }
24940b57cec5SDimitry Andric 
24950b57cec5SDimitry Andric static Value *insertInteger(const DataLayout &DL, IRBuilderTy &IRB, Value *Old,
24960b57cec5SDimitry Andric                             Value *V, uint64_t Offset, const Twine &Name) {
24970b57cec5SDimitry Andric   IntegerType *IntTy = cast<IntegerType>(Old->getType());
24980b57cec5SDimitry Andric   IntegerType *Ty = cast<IntegerType>(V->getType());
24990b57cec5SDimitry Andric   assert(Ty->getBitWidth() <= IntTy->getBitWidth() &&
25000b57cec5SDimitry Andric          "Cannot insert a larger integer!");
25010b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "       start: " << *V << "\n");
25020b57cec5SDimitry Andric   if (Ty != IntTy) {
25030b57cec5SDimitry Andric     V = IRB.CreateZExt(V, IntTy, Name + ".ext");
25040b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    extended: " << *V << "\n");
25050b57cec5SDimitry Andric   }
2506bdd1243dSDimitry Andric   assert(DL.getTypeStoreSize(Ty).getFixedValue() + Offset <=
2507bdd1243dSDimitry Andric              DL.getTypeStoreSize(IntTy).getFixedValue() &&
25080b57cec5SDimitry Andric          "Element store outside of alloca store");
25090b57cec5SDimitry Andric   uint64_t ShAmt = 8 * Offset;
25100b57cec5SDimitry Andric   if (DL.isBigEndian())
2511bdd1243dSDimitry Andric     ShAmt = 8 * (DL.getTypeStoreSize(IntTy).getFixedValue() -
2512bdd1243dSDimitry Andric                  DL.getTypeStoreSize(Ty).getFixedValue() - Offset);
25130b57cec5SDimitry Andric   if (ShAmt) {
25140b57cec5SDimitry Andric     V = IRB.CreateShl(V, ShAmt, Name + ".shift");
25150b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "     shifted: " << *V << "\n");
25160b57cec5SDimitry Andric   }
25170b57cec5SDimitry Andric 
25180b57cec5SDimitry Andric   if (ShAmt || Ty->getBitWidth() < IntTy->getBitWidth()) {
25190b57cec5SDimitry Andric     APInt Mask = ~Ty->getMask().zext(IntTy->getBitWidth()).shl(ShAmt);
25200b57cec5SDimitry Andric     Old = IRB.CreateAnd(Old, Mask, Name + ".mask");
25210b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "      masked: " << *Old << "\n");
25220b57cec5SDimitry Andric     V = IRB.CreateOr(Old, V, Name + ".insert");
25230b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    inserted: " << *V << "\n");
25240b57cec5SDimitry Andric   }
25250b57cec5SDimitry Andric   return V;
25260b57cec5SDimitry Andric }
25270b57cec5SDimitry Andric 
25280b57cec5SDimitry Andric static Value *extractVector(IRBuilderTy &IRB, Value *V, unsigned BeginIndex,
25290b57cec5SDimitry Andric                             unsigned EndIndex, const Twine &Name) {
25305ffd83dbSDimitry Andric   auto *VecTy = cast<FixedVectorType>(V->getType());
25310b57cec5SDimitry Andric   unsigned NumElements = EndIndex - BeginIndex;
25320b57cec5SDimitry Andric   assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
25330b57cec5SDimitry Andric 
25340b57cec5SDimitry Andric   if (NumElements == VecTy->getNumElements())
25350b57cec5SDimitry Andric     return V;
25360b57cec5SDimitry Andric 
25370b57cec5SDimitry Andric   if (NumElements == 1) {
25380b57cec5SDimitry Andric     V = IRB.CreateExtractElement(V, IRB.getInt32(BeginIndex),
25390b57cec5SDimitry Andric                                  Name + ".extract");
25400b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "     extract: " << *V << "\n");
25410b57cec5SDimitry Andric     return V;
25420b57cec5SDimitry Andric   }
25430b57cec5SDimitry Andric 
254481ad6265SDimitry Andric   auto Mask = llvm::to_vector<8>(llvm::seq<int>(BeginIndex, EndIndex));
2545e8d8bef9SDimitry Andric   V = IRB.CreateShuffleVector(V, Mask, Name + ".extract");
25460b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "     shuffle: " << *V << "\n");
25470b57cec5SDimitry Andric   return V;
25480b57cec5SDimitry Andric }
25490b57cec5SDimitry Andric 
25500b57cec5SDimitry Andric static Value *insertVector(IRBuilderTy &IRB, Value *Old, Value *V,
25510b57cec5SDimitry Andric                            unsigned BeginIndex, const Twine &Name) {
25520b57cec5SDimitry Andric   VectorType *VecTy = cast<VectorType>(Old->getType());
25530b57cec5SDimitry Andric   assert(VecTy && "Can only insert a vector into a vector");
25540b57cec5SDimitry Andric 
25550b57cec5SDimitry Andric   VectorType *Ty = dyn_cast<VectorType>(V->getType());
25560b57cec5SDimitry Andric   if (!Ty) {
25570b57cec5SDimitry Andric     // Single element to insert.
25580b57cec5SDimitry Andric     V = IRB.CreateInsertElement(Old, V, IRB.getInt32(BeginIndex),
25590b57cec5SDimitry Andric                                 Name + ".insert");
25600b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "     insert: " << *V << "\n");
25610b57cec5SDimitry Andric     return V;
25620b57cec5SDimitry Andric   }
25630b57cec5SDimitry Andric 
25645ffd83dbSDimitry Andric   assert(cast<FixedVectorType>(Ty)->getNumElements() <=
25655ffd83dbSDimitry Andric              cast<FixedVectorType>(VecTy)->getNumElements() &&
25660b57cec5SDimitry Andric          "Too many elements!");
25675ffd83dbSDimitry Andric   if (cast<FixedVectorType>(Ty)->getNumElements() ==
25685ffd83dbSDimitry Andric       cast<FixedVectorType>(VecTy)->getNumElements()) {
25690b57cec5SDimitry Andric     assert(V->getType() == VecTy && "Vector type mismatch");
25700b57cec5SDimitry Andric     return V;
25710b57cec5SDimitry Andric   }
25725ffd83dbSDimitry Andric   unsigned EndIndex = BeginIndex + cast<FixedVectorType>(Ty)->getNumElements();
25730b57cec5SDimitry Andric 
25740b57cec5SDimitry Andric   // When inserting a smaller vector into the larger to store, we first
25750b57cec5SDimitry Andric   // use a shuffle vector to widen it with undef elements, and then
25760b57cec5SDimitry Andric   // a second shuffle vector to select between the loaded vector and the
25770b57cec5SDimitry Andric   // incoming vector.
2578e8d8bef9SDimitry Andric   SmallVector<int, 8> Mask;
25795ffd83dbSDimitry Andric   Mask.reserve(cast<FixedVectorType>(VecTy)->getNumElements());
25805ffd83dbSDimitry Andric   for (unsigned i = 0; i != cast<FixedVectorType>(VecTy)->getNumElements(); ++i)
25810b57cec5SDimitry Andric     if (i >= BeginIndex && i < EndIndex)
2582e8d8bef9SDimitry Andric       Mask.push_back(i - BeginIndex);
25830b57cec5SDimitry Andric     else
2584e8d8bef9SDimitry Andric       Mask.push_back(-1);
2585e8d8bef9SDimitry Andric   V = IRB.CreateShuffleVector(V, Mask, Name + ".expand");
25860b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "    shuffle: " << *V << "\n");
25870b57cec5SDimitry Andric 
2588e8d8bef9SDimitry Andric   SmallVector<Constant *, 8> Mask2;
2589e8d8bef9SDimitry Andric   Mask2.reserve(cast<FixedVectorType>(VecTy)->getNumElements());
25905ffd83dbSDimitry Andric   for (unsigned i = 0; i != cast<FixedVectorType>(VecTy)->getNumElements(); ++i)
2591e8d8bef9SDimitry Andric     Mask2.push_back(IRB.getInt1(i >= BeginIndex && i < EndIndex));
25920b57cec5SDimitry Andric 
2593e8d8bef9SDimitry Andric   V = IRB.CreateSelect(ConstantVector::get(Mask2), V, Old, Name + "blend");
25940b57cec5SDimitry Andric 
25950b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "    blend: " << *V << "\n");
25960b57cec5SDimitry Andric   return V;
25970b57cec5SDimitry Andric }
25980b57cec5SDimitry Andric 
25995f757f3fSDimitry Andric namespace {
26005f757f3fSDimitry Andric 
26010b57cec5SDimitry Andric /// Visitor to rewrite instructions using p particular slice of an alloca
26020b57cec5SDimitry Andric /// to use a new alloca.
26030b57cec5SDimitry Andric ///
26040b57cec5SDimitry Andric /// Also implements the rewriting to vector-based accesses when the partition
26050b57cec5SDimitry Andric /// passes the isVectorPromotionViable predicate. Most of the rewriting logic
26060b57cec5SDimitry Andric /// lives here.
26075f757f3fSDimitry Andric class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
26080b57cec5SDimitry Andric   // Befriend the base class so it can delegate to private visit methods.
26090b57cec5SDimitry Andric   friend class InstVisitor<AllocaSliceRewriter, bool>;
26100b57cec5SDimitry Andric 
26110b57cec5SDimitry Andric   using Base = InstVisitor<AllocaSliceRewriter, bool>;
26120b57cec5SDimitry Andric 
26130b57cec5SDimitry Andric   const DataLayout &DL;
26140b57cec5SDimitry Andric   AllocaSlices &AS;
26155f757f3fSDimitry Andric   SROA &Pass;
26160b57cec5SDimitry Andric   AllocaInst &OldAI, &NewAI;
26170b57cec5SDimitry Andric   const uint64_t NewAllocaBeginOffset, NewAllocaEndOffset;
26180b57cec5SDimitry Andric   Type *NewAllocaTy;
26190b57cec5SDimitry Andric 
26200b57cec5SDimitry Andric   // This is a convenience and flag variable that will be null unless the new
26210b57cec5SDimitry Andric   // alloca's integer operations should be widened to this integer type due to
26220b57cec5SDimitry Andric   // passing isIntegerWideningViable above. If it is non-null, the desired
26230b57cec5SDimitry Andric   // integer type will be stored here for easy access during rewriting.
26240b57cec5SDimitry Andric   IntegerType *IntTy;
26250b57cec5SDimitry Andric 
26260b57cec5SDimitry Andric   // If we are rewriting an alloca partition which can be written as pure
26270b57cec5SDimitry Andric   // vector operations, we stash extra information here. When VecTy is
26280b57cec5SDimitry Andric   // non-null, we have some strict guarantees about the rewritten alloca:
26290b57cec5SDimitry Andric   //   - The new alloca is exactly the size of the vector type here.
26300b57cec5SDimitry Andric   //   - The accesses all either map to the entire vector or to a single
26310b57cec5SDimitry Andric   //     element.
26320b57cec5SDimitry Andric   //   - The set of accessing instructions is only one of those handled above
26330b57cec5SDimitry Andric   //     in isVectorPromotionViable. Generally these are the same access kinds
26340b57cec5SDimitry Andric   //     which are promotable via mem2reg.
26350b57cec5SDimitry Andric   VectorType *VecTy;
26360b57cec5SDimitry Andric   Type *ElementTy;
26370b57cec5SDimitry Andric   uint64_t ElementSize;
26380b57cec5SDimitry Andric 
26390b57cec5SDimitry Andric   // The original offset of the slice currently being rewritten relative to
26400b57cec5SDimitry Andric   // the original alloca.
26410b57cec5SDimitry Andric   uint64_t BeginOffset = 0;
26420b57cec5SDimitry Andric   uint64_t EndOffset = 0;
26430b57cec5SDimitry Andric 
26440b57cec5SDimitry Andric   // The new offsets of the slice currently being rewritten relative to the
26450b57cec5SDimitry Andric   // original alloca.
2646480093f4SDimitry Andric   uint64_t NewBeginOffset = 0, NewEndOffset = 0;
26470b57cec5SDimitry Andric 
2648480093f4SDimitry Andric   uint64_t SliceSize = 0;
26490b57cec5SDimitry Andric   bool IsSplittable = false;
26500b57cec5SDimitry Andric   bool IsSplit = false;
26510b57cec5SDimitry Andric   Use *OldUse = nullptr;
26520b57cec5SDimitry Andric   Instruction *OldPtr = nullptr;
26530b57cec5SDimitry Andric 
26540b57cec5SDimitry Andric   // Track post-rewrite users which are PHI nodes and Selects.
26550b57cec5SDimitry Andric   SmallSetVector<PHINode *, 8> &PHIUsers;
26560b57cec5SDimitry Andric   SmallSetVector<SelectInst *, 8> &SelectUsers;
26570b57cec5SDimitry Andric 
26580b57cec5SDimitry Andric   // Utility IR builder, whose name prefix is setup for each visited use, and
26590b57cec5SDimitry Andric   // the insertion point is set to point to the user.
26600b57cec5SDimitry Andric   IRBuilderTy IRB;
26610b57cec5SDimitry Andric 
2662bdd1243dSDimitry Andric   // Return the new alloca, addrspacecasted if required to avoid changing the
2663bdd1243dSDimitry Andric   // addrspace of a volatile access.
2664bdd1243dSDimitry Andric   Value *getPtrToNewAI(unsigned AddrSpace, bool IsVolatile) {
2665bdd1243dSDimitry Andric     if (!IsVolatile || AddrSpace == NewAI.getType()->getPointerAddressSpace())
2666bdd1243dSDimitry Andric       return &NewAI;
2667bdd1243dSDimitry Andric 
26685f757f3fSDimitry Andric     Type *AccessTy = IRB.getPtrTy(AddrSpace);
2669bdd1243dSDimitry Andric     return IRB.CreateAddrSpaceCast(&NewAI, AccessTy);
2670bdd1243dSDimitry Andric   }
2671bdd1243dSDimitry Andric 
26720b57cec5SDimitry Andric public:
26735f757f3fSDimitry Andric   AllocaSliceRewriter(const DataLayout &DL, AllocaSlices &AS, SROA &Pass,
26740b57cec5SDimitry Andric                       AllocaInst &OldAI, AllocaInst &NewAI,
26750b57cec5SDimitry Andric                       uint64_t NewAllocaBeginOffset,
26760b57cec5SDimitry Andric                       uint64_t NewAllocaEndOffset, bool IsIntegerPromotable,
26770b57cec5SDimitry Andric                       VectorType *PromotableVecTy,
26780b57cec5SDimitry Andric                       SmallSetVector<PHINode *, 8> &PHIUsers,
26790b57cec5SDimitry Andric                       SmallSetVector<SelectInst *, 8> &SelectUsers)
26800b57cec5SDimitry Andric       : DL(DL), AS(AS), Pass(Pass), OldAI(OldAI), NewAI(NewAI),
26810b57cec5SDimitry Andric         NewAllocaBeginOffset(NewAllocaBeginOffset),
26820b57cec5SDimitry Andric         NewAllocaEndOffset(NewAllocaEndOffset),
26830b57cec5SDimitry Andric         NewAllocaTy(NewAI.getAllocatedType()),
26845ffd83dbSDimitry Andric         IntTy(
26855ffd83dbSDimitry Andric             IsIntegerPromotable
26865ffd83dbSDimitry Andric                 ? Type::getIntNTy(NewAI.getContext(),
26875ffd83dbSDimitry Andric                                   DL.getTypeSizeInBits(NewAI.getAllocatedType())
2688bdd1243dSDimitry Andric                                       .getFixedValue())
26890b57cec5SDimitry Andric                 : nullptr),
26900b57cec5SDimitry Andric         VecTy(PromotableVecTy),
26910b57cec5SDimitry Andric         ElementTy(VecTy ? VecTy->getElementType() : nullptr),
2692bdd1243dSDimitry Andric         ElementSize(VecTy ? DL.getTypeSizeInBits(ElementTy).getFixedValue() / 8
26935ffd83dbSDimitry Andric                           : 0),
26940b57cec5SDimitry Andric         PHIUsers(PHIUsers), SelectUsers(SelectUsers),
26950b57cec5SDimitry Andric         IRB(NewAI.getContext(), ConstantFolder()) {
26960b57cec5SDimitry Andric     if (VecTy) {
2697bdd1243dSDimitry Andric       assert((DL.getTypeSizeInBits(ElementTy).getFixedValue() % 8) == 0 &&
26980b57cec5SDimitry Andric              "Only multiple-of-8 sized vector elements are viable");
26990b57cec5SDimitry Andric       ++NumVectorized;
27000b57cec5SDimitry Andric     }
27010b57cec5SDimitry Andric     assert((!IntTy && !VecTy) || (IntTy && !VecTy) || (!IntTy && VecTy));
27020b57cec5SDimitry Andric   }
27030b57cec5SDimitry Andric 
27040b57cec5SDimitry Andric   bool visit(AllocaSlices::const_iterator I) {
27050b57cec5SDimitry Andric     bool CanSROA = true;
27060b57cec5SDimitry Andric     BeginOffset = I->beginOffset();
27070b57cec5SDimitry Andric     EndOffset = I->endOffset();
27080b57cec5SDimitry Andric     IsSplittable = I->isSplittable();
27090b57cec5SDimitry Andric     IsSplit =
27100b57cec5SDimitry Andric         BeginOffset < NewAllocaBeginOffset || EndOffset > NewAllocaEndOffset;
27110b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "  rewriting " << (IsSplit ? "split " : ""));
27120b57cec5SDimitry Andric     LLVM_DEBUG(AS.printSlice(dbgs(), I, ""));
27130b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "\n");
27140b57cec5SDimitry Andric 
27150b57cec5SDimitry Andric     // Compute the intersecting offset range.
27160b57cec5SDimitry Andric     assert(BeginOffset < NewAllocaEndOffset);
27170b57cec5SDimitry Andric     assert(EndOffset > NewAllocaBeginOffset);
27180b57cec5SDimitry Andric     NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
27190b57cec5SDimitry Andric     NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
27200b57cec5SDimitry Andric 
27210b57cec5SDimitry Andric     SliceSize = NewEndOffset - NewBeginOffset;
2722bdd1243dSDimitry Andric     LLVM_DEBUG(dbgs() << "   Begin:(" << BeginOffset << ", " << EndOffset
2723bdd1243dSDimitry Andric                       << ") NewBegin:(" << NewBeginOffset << ", "
2724bdd1243dSDimitry Andric                       << NewEndOffset << ") NewAllocaBegin:("
2725bdd1243dSDimitry Andric                       << NewAllocaBeginOffset << ", " << NewAllocaEndOffset
2726bdd1243dSDimitry Andric                       << ")\n");
272706c3fb27SDimitry Andric     assert(IsSplit || NewBeginOffset == BeginOffset);
27280b57cec5SDimitry Andric     OldUse = I->getUse();
27290b57cec5SDimitry Andric     OldPtr = cast<Instruction>(OldUse->get());
27300b57cec5SDimitry Andric 
27310b57cec5SDimitry Andric     Instruction *OldUserI = cast<Instruction>(OldUse->getUser());
27320b57cec5SDimitry Andric     IRB.SetInsertPoint(OldUserI);
27330b57cec5SDimitry Andric     IRB.SetCurrentDebugLocation(OldUserI->getDebugLoc());
2734*0fca6ea1SDimitry Andric     IRB.getInserter().SetNamePrefix(Twine(NewAI.getName()) + "." +
2735*0fca6ea1SDimitry Andric                                     Twine(BeginOffset) + ".");
27360b57cec5SDimitry Andric 
27370b57cec5SDimitry Andric     CanSROA &= visit(cast<Instruction>(OldUse->getUser()));
27380b57cec5SDimitry Andric     if (VecTy || IntTy)
27390b57cec5SDimitry Andric       assert(CanSROA);
27400b57cec5SDimitry Andric     return CanSROA;
27410b57cec5SDimitry Andric   }
27420b57cec5SDimitry Andric 
27430b57cec5SDimitry Andric private:
27440b57cec5SDimitry Andric   // Make sure the other visit overloads are visible.
27450b57cec5SDimitry Andric   using Base::visit;
27460b57cec5SDimitry Andric 
27470b57cec5SDimitry Andric   // Every instruction which can end up as a user must have a rewrite rule.
27480b57cec5SDimitry Andric   bool visitInstruction(Instruction &I) {
27490b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    !!!! Cannot rewrite: " << I << "\n");
27500b57cec5SDimitry Andric     llvm_unreachable("No rewrite rule for this instruction!");
27510b57cec5SDimitry Andric   }
27520b57cec5SDimitry Andric 
27530b57cec5SDimitry Andric   Value *getNewAllocaSlicePtr(IRBuilderTy &IRB, Type *PointerTy) {
27540b57cec5SDimitry Andric     // Note that the offset computation can use BeginOffset or NewBeginOffset
27550b57cec5SDimitry Andric     // interchangeably for unsplit slices.
27560b57cec5SDimitry Andric     assert(IsSplit || BeginOffset == NewBeginOffset);
27570b57cec5SDimitry Andric     uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
27580b57cec5SDimitry Andric 
27590b57cec5SDimitry Andric #ifndef NDEBUG
27600b57cec5SDimitry Andric     StringRef OldName = OldPtr->getName();
27610b57cec5SDimitry Andric     // Skip through the last '.sroa.' component of the name.
27620b57cec5SDimitry Andric     size_t LastSROAPrefix = OldName.rfind(".sroa.");
27630b57cec5SDimitry Andric     if (LastSROAPrefix != StringRef::npos) {
27640b57cec5SDimitry Andric       OldName = OldName.substr(LastSROAPrefix + strlen(".sroa."));
27650b57cec5SDimitry Andric       // Look for an SROA slice index.
27660b57cec5SDimitry Andric       size_t IndexEnd = OldName.find_first_not_of("0123456789");
27670b57cec5SDimitry Andric       if (IndexEnd != StringRef::npos && OldName[IndexEnd] == '.') {
27680b57cec5SDimitry Andric         // Strip the index and look for the offset.
27690b57cec5SDimitry Andric         OldName = OldName.substr(IndexEnd + 1);
27700b57cec5SDimitry Andric         size_t OffsetEnd = OldName.find_first_not_of("0123456789");
27710b57cec5SDimitry Andric         if (OffsetEnd != StringRef::npos && OldName[OffsetEnd] == '.')
27720b57cec5SDimitry Andric           // Strip the offset.
27730b57cec5SDimitry Andric           OldName = OldName.substr(OffsetEnd + 1);
27740b57cec5SDimitry Andric       }
27750b57cec5SDimitry Andric     }
27760b57cec5SDimitry Andric     // Strip any SROA suffixes as well.
27770b57cec5SDimitry Andric     OldName = OldName.substr(0, OldName.find(".sroa_"));
27780b57cec5SDimitry Andric #endif
27790b57cec5SDimitry Andric 
27800b57cec5SDimitry Andric     return getAdjustedPtr(IRB, DL, &NewAI,
27810b57cec5SDimitry Andric                           APInt(DL.getIndexTypeSizeInBits(PointerTy), Offset),
27820b57cec5SDimitry Andric                           PointerTy,
27830b57cec5SDimitry Andric #ifndef NDEBUG
27840b57cec5SDimitry Andric                           Twine(OldName) + "."
27850b57cec5SDimitry Andric #else
27860b57cec5SDimitry Andric                           Twine()
27870b57cec5SDimitry Andric #endif
27880b57cec5SDimitry Andric     );
27890b57cec5SDimitry Andric   }
27900b57cec5SDimitry Andric 
27910b57cec5SDimitry Andric   /// Compute suitable alignment to access this slice of the *new*
27920b57cec5SDimitry Andric   /// alloca.
27930b57cec5SDimitry Andric   ///
27940b57cec5SDimitry Andric   /// You can optionally pass a type to this routine and if that type's ABI
27950b57cec5SDimitry Andric   /// alignment is itself suitable, this will return zero.
27965ffd83dbSDimitry Andric   Align getSliceAlign() {
27975ffd83dbSDimitry Andric     return commonAlignment(NewAI.getAlign(),
27985ffd83dbSDimitry Andric                            NewBeginOffset - NewAllocaBeginOffset);
27990b57cec5SDimitry Andric   }
28000b57cec5SDimitry Andric 
28010b57cec5SDimitry Andric   unsigned getIndex(uint64_t Offset) {
28020b57cec5SDimitry Andric     assert(VecTy && "Can only call getIndex when rewriting a vector");
28030b57cec5SDimitry Andric     uint64_t RelOffset = Offset - NewAllocaBeginOffset;
28040b57cec5SDimitry Andric     assert(RelOffset / ElementSize < UINT32_MAX && "Index out of bounds");
28050b57cec5SDimitry Andric     uint32_t Index = RelOffset / ElementSize;
28060b57cec5SDimitry Andric     assert(Index * ElementSize == RelOffset);
28070b57cec5SDimitry Andric     return Index;
28080b57cec5SDimitry Andric   }
28090b57cec5SDimitry Andric 
28100b57cec5SDimitry Andric   void deleteIfTriviallyDead(Value *V) {
28110b57cec5SDimitry Andric     Instruction *I = cast<Instruction>(V);
28120b57cec5SDimitry Andric     if (isInstructionTriviallyDead(I))
2813e8d8bef9SDimitry Andric       Pass.DeadInsts.push_back(I);
28140b57cec5SDimitry Andric   }
28150b57cec5SDimitry Andric 
2816fe6060f1SDimitry Andric   Value *rewriteVectorizedLoadInst(LoadInst &LI) {
28170b57cec5SDimitry Andric     unsigned BeginIndex = getIndex(NewBeginOffset);
28180b57cec5SDimitry Andric     unsigned EndIndex = getIndex(NewEndOffset);
28190b57cec5SDimitry Andric     assert(EndIndex > BeginIndex && "Empty vector!");
28200b57cec5SDimitry Andric 
2821fe6060f1SDimitry Andric     LoadInst *Load = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
28225ffd83dbSDimitry Andric                                            NewAI.getAlign(), "load");
2823fe6060f1SDimitry Andric 
2824fe6060f1SDimitry Andric     Load->copyMetadata(LI, {LLVMContext::MD_mem_parallel_loop_access,
2825fe6060f1SDimitry Andric                             LLVMContext::MD_access_group});
2826fe6060f1SDimitry Andric     return extractVector(IRB, Load, BeginIndex, EndIndex, "vec");
28270b57cec5SDimitry Andric   }
28280b57cec5SDimitry Andric 
28290b57cec5SDimitry Andric   Value *rewriteIntegerLoad(LoadInst &LI) {
28300b57cec5SDimitry Andric     assert(IntTy && "We cannot insert an integer to the alloca");
28310b57cec5SDimitry Andric     assert(!LI.isVolatile());
28320b57cec5SDimitry Andric     Value *V = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
28335ffd83dbSDimitry Andric                                      NewAI.getAlign(), "load");
28340b57cec5SDimitry Andric     V = convertValue(DL, IRB, V, IntTy);
28350b57cec5SDimitry Andric     assert(NewBeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
28360b57cec5SDimitry Andric     uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
28370b57cec5SDimitry Andric     if (Offset > 0 || NewEndOffset < NewAllocaEndOffset) {
28380b57cec5SDimitry Andric       IntegerType *ExtractTy = Type::getIntNTy(LI.getContext(), SliceSize * 8);
28390b57cec5SDimitry Andric       V = extractInteger(DL, IRB, V, ExtractTy, Offset, "extract");
28400b57cec5SDimitry Andric     }
28410b57cec5SDimitry Andric     // It is possible that the extracted type is not the load type. This
28420b57cec5SDimitry Andric     // happens if there is a load past the end of the alloca, and as
28430b57cec5SDimitry Andric     // a consequence the slice is narrower but still a candidate for integer
28440b57cec5SDimitry Andric     // lowering. To handle this case, we just zero extend the extracted
28450b57cec5SDimitry Andric     // integer.
28460b57cec5SDimitry Andric     assert(cast<IntegerType>(LI.getType())->getBitWidth() >= SliceSize * 8 &&
28470b57cec5SDimitry Andric            "Can only handle an extract for an overly wide load");
28480b57cec5SDimitry Andric     if (cast<IntegerType>(LI.getType())->getBitWidth() > SliceSize * 8)
28490b57cec5SDimitry Andric       V = IRB.CreateZExt(V, LI.getType());
28500b57cec5SDimitry Andric     return V;
28510b57cec5SDimitry Andric   }
28520b57cec5SDimitry Andric 
28530b57cec5SDimitry Andric   bool visitLoadInst(LoadInst &LI) {
28540b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << LI << "\n");
28550b57cec5SDimitry Andric     Value *OldOp = LI.getOperand(0);
28560b57cec5SDimitry Andric     assert(OldOp == OldPtr);
28570b57cec5SDimitry Andric 
2858349cc55cSDimitry Andric     AAMDNodes AATags = LI.getAAMetadata();
28590b57cec5SDimitry Andric 
28600b57cec5SDimitry Andric     unsigned AS = LI.getPointerAddressSpace();
28610b57cec5SDimitry Andric 
28620b57cec5SDimitry Andric     Type *TargetTy = IsSplit ? Type::getIntNTy(LI.getContext(), SliceSize * 8)
28630b57cec5SDimitry Andric                              : LI.getType();
28645ffd83dbSDimitry Andric     const bool IsLoadPastEnd =
2865bdd1243dSDimitry Andric         DL.getTypeStoreSize(TargetTy).getFixedValue() > SliceSize;
28660b57cec5SDimitry Andric     bool IsPtrAdjusted = false;
28670b57cec5SDimitry Andric     Value *V;
28680b57cec5SDimitry Andric     if (VecTy) {
2869fe6060f1SDimitry Andric       V = rewriteVectorizedLoadInst(LI);
28700b57cec5SDimitry Andric     } else if (IntTy && LI.getType()->isIntegerTy()) {
28710b57cec5SDimitry Andric       V = rewriteIntegerLoad(LI);
28720b57cec5SDimitry Andric     } else if (NewBeginOffset == NewAllocaBeginOffset &&
28730b57cec5SDimitry Andric                NewEndOffset == NewAllocaEndOffset &&
28740b57cec5SDimitry Andric                (canConvertValue(DL, NewAllocaTy, TargetTy) ||
28750b57cec5SDimitry Andric                 (IsLoadPastEnd && NewAllocaTy->isIntegerTy() &&
28765f757f3fSDimitry Andric                  TargetTy->isIntegerTy() && !LI.isVolatile()))) {
2877bdd1243dSDimitry Andric       Value *NewPtr =
2878bdd1243dSDimitry Andric           getPtrToNewAI(LI.getPointerAddressSpace(), LI.isVolatile());
2879bdd1243dSDimitry Andric       LoadInst *NewLI = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), NewPtr,
28805ffd83dbSDimitry Andric                                               NewAI.getAlign(), LI.isVolatile(),
28815ffd83dbSDimitry Andric                                               LI.getName());
28820b57cec5SDimitry Andric       if (LI.isVolatile())
28830b57cec5SDimitry Andric         NewLI->setAtomic(LI.getOrdering(), LI.getSyncScopeID());
28848c27c554SDimitry Andric       if (NewLI->isAtomic())
28858c27c554SDimitry Andric         NewLI->setAlignment(LI.getAlign());
28860b57cec5SDimitry Andric 
2887bdd1243dSDimitry Andric       // Copy any metadata that is valid for the new load. This may require
2888bdd1243dSDimitry Andric       // conversion to a different kind of metadata, e.g. !nonnull might change
2889bdd1243dSDimitry Andric       // to !range or vice versa.
2890bdd1243dSDimitry Andric       copyMetadataForLoad(*NewLI, LI);
2891bdd1243dSDimitry Andric 
2892bdd1243dSDimitry Andric       // Do this after copyMetadataForLoad() to preserve the TBAA shift.
2893bdd1243dSDimitry Andric       if (AATags)
2894*0fca6ea1SDimitry Andric         NewLI->setAAMetadata(AATags.adjustForAccess(
2895*0fca6ea1SDimitry Andric             NewBeginOffset - BeginOffset, NewLI->getType(), DL));
28960b57cec5SDimitry Andric 
28970b57cec5SDimitry Andric       // Try to preserve nonnull metadata
28980b57cec5SDimitry Andric       V = NewLI;
28990b57cec5SDimitry Andric 
29000b57cec5SDimitry Andric       // If this is an integer load past the end of the slice (which means the
29010b57cec5SDimitry Andric       // bytes outside the slice are undef or this load is dead) just forcibly
29020b57cec5SDimitry Andric       // fix the integer size with correct handling of endianness.
29030b57cec5SDimitry Andric       if (auto *AITy = dyn_cast<IntegerType>(NewAllocaTy))
29040b57cec5SDimitry Andric         if (auto *TITy = dyn_cast<IntegerType>(TargetTy))
29050b57cec5SDimitry Andric           if (AITy->getBitWidth() < TITy->getBitWidth()) {
29060b57cec5SDimitry Andric             V = IRB.CreateZExt(V, TITy, "load.ext");
29070b57cec5SDimitry Andric             if (DL.isBigEndian())
29080b57cec5SDimitry Andric               V = IRB.CreateShl(V, TITy->getBitWidth() - AITy->getBitWidth(),
29090b57cec5SDimitry Andric                                 "endian_shift");
29100b57cec5SDimitry Andric           }
29110b57cec5SDimitry Andric     } else {
29125f757f3fSDimitry Andric       Type *LTy = IRB.getPtrTy(AS);
29135ffd83dbSDimitry Andric       LoadInst *NewLI =
29145ffd83dbSDimitry Andric           IRB.CreateAlignedLoad(TargetTy, getNewAllocaSlicePtr(IRB, LTy),
29155ffd83dbSDimitry Andric                                 getSliceAlign(), LI.isVolatile(), LI.getName());
2916*0fca6ea1SDimitry Andric 
29170b57cec5SDimitry Andric       if (AATags)
2918*0fca6ea1SDimitry Andric         NewLI->setAAMetadata(AATags.adjustForAccess(
2919*0fca6ea1SDimitry Andric             NewBeginOffset - BeginOffset, NewLI->getType(), DL));
2920*0fca6ea1SDimitry Andric 
29210b57cec5SDimitry Andric       if (LI.isVolatile())
29220b57cec5SDimitry Andric         NewLI->setAtomic(LI.getOrdering(), LI.getSyncScopeID());
2923fe6060f1SDimitry Andric       NewLI->copyMetadata(LI, {LLVMContext::MD_mem_parallel_loop_access,
2924fe6060f1SDimitry Andric                                LLVMContext::MD_access_group});
29250b57cec5SDimitry Andric 
29260b57cec5SDimitry Andric       V = NewLI;
29270b57cec5SDimitry Andric       IsPtrAdjusted = true;
29280b57cec5SDimitry Andric     }
29290b57cec5SDimitry Andric     V = convertValue(DL, IRB, V, TargetTy);
29300b57cec5SDimitry Andric 
29310b57cec5SDimitry Andric     if (IsSplit) {
29320b57cec5SDimitry Andric       assert(!LI.isVolatile());
29330b57cec5SDimitry Andric       assert(LI.getType()->isIntegerTy() &&
29340b57cec5SDimitry Andric              "Only integer type loads and stores are split");
2935bdd1243dSDimitry Andric       assert(SliceSize < DL.getTypeStoreSize(LI.getType()).getFixedValue() &&
29360b57cec5SDimitry Andric              "Split load isn't smaller than original load");
29370b57cec5SDimitry Andric       assert(DL.typeSizeEqualsStoreSize(LI.getType()) &&
29380b57cec5SDimitry Andric              "Non-byte-multiple bit width");
29390b57cec5SDimitry Andric       // Move the insertion point just past the load so that we can refer to it.
2940*0fca6ea1SDimitry Andric       BasicBlock::iterator LIIt = std::next(LI.getIterator());
2941*0fca6ea1SDimitry Andric       // Ensure the insertion point comes before any debug-info immediately
2942*0fca6ea1SDimitry Andric       // after the load, so that variable values referring to the load are
2943*0fca6ea1SDimitry Andric       // dominated by it.
2944*0fca6ea1SDimitry Andric       LIIt.setHeadBit(true);
2945*0fca6ea1SDimitry Andric       IRB.SetInsertPoint(LI.getParent(), LIIt);
29460b57cec5SDimitry Andric       // Create a placeholder value with the same type as LI to use as the
29470b57cec5SDimitry Andric       // basis for the new value. This allows us to replace the uses of LI with
29480b57cec5SDimitry Andric       // the computed value, and then replace the placeholder with LI, leaving
29490b57cec5SDimitry Andric       // LI only used for this computation.
29505f757f3fSDimitry Andric       Value *Placeholder =
29515f757f3fSDimitry Andric           new LoadInst(LI.getType(), PoisonValue::get(IRB.getPtrTy(AS)), "",
29525ffd83dbSDimitry Andric                        false, Align(1));
29530b57cec5SDimitry Andric       V = insertInteger(DL, IRB, Placeholder, V, NewBeginOffset - BeginOffset,
29540b57cec5SDimitry Andric                         "insert");
29550b57cec5SDimitry Andric       LI.replaceAllUsesWith(V);
29560b57cec5SDimitry Andric       Placeholder->replaceAllUsesWith(&LI);
29570b57cec5SDimitry Andric       Placeholder->deleteValue();
29580b57cec5SDimitry Andric     } else {
29590b57cec5SDimitry Andric       LI.replaceAllUsesWith(V);
29600b57cec5SDimitry Andric     }
29610b57cec5SDimitry Andric 
2962e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&LI);
29630b57cec5SDimitry Andric     deleteIfTriviallyDead(OldOp);
29640b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *V << "\n");
29650b57cec5SDimitry Andric     return !LI.isVolatile() && !IsPtrAdjusted;
29660b57cec5SDimitry Andric   }
29670b57cec5SDimitry Andric 
29680b57cec5SDimitry Andric   bool rewriteVectorizedStoreInst(Value *V, StoreInst &SI, Value *OldOp,
29690b57cec5SDimitry Andric                                   AAMDNodes AATags) {
2970bdd1243dSDimitry Andric     // Capture V for the purpose of debug-info accounting once it's converted
2971bdd1243dSDimitry Andric     // to a vector store.
2972bdd1243dSDimitry Andric     Value *OrigV = V;
29730b57cec5SDimitry Andric     if (V->getType() != VecTy) {
29740b57cec5SDimitry Andric       unsigned BeginIndex = getIndex(NewBeginOffset);
29750b57cec5SDimitry Andric       unsigned EndIndex = getIndex(NewEndOffset);
29760b57cec5SDimitry Andric       assert(EndIndex > BeginIndex && "Empty vector!");
29770b57cec5SDimitry Andric       unsigned NumElements = EndIndex - BeginIndex;
29785ffd83dbSDimitry Andric       assert(NumElements <= cast<FixedVectorType>(VecTy)->getNumElements() &&
29795ffd83dbSDimitry Andric              "Too many elements!");
29800b57cec5SDimitry Andric       Type *SliceTy = (NumElements == 1)
29810b57cec5SDimitry Andric                           ? ElementTy
29825ffd83dbSDimitry Andric                           : FixedVectorType::get(ElementTy, NumElements);
29830b57cec5SDimitry Andric       if (V->getType() != SliceTy)
29840b57cec5SDimitry Andric         V = convertValue(DL, IRB, V, SliceTy);
29850b57cec5SDimitry Andric 
29860b57cec5SDimitry Andric       // Mix in the existing elements.
29870b57cec5SDimitry Andric       Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
29885ffd83dbSDimitry Andric                                          NewAI.getAlign(), "load");
29890b57cec5SDimitry Andric       V = insertVector(IRB, Old, V, BeginIndex, "vec");
29900b57cec5SDimitry Andric     }
29915ffd83dbSDimitry Andric     StoreInst *Store = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlign());
2992fe6060f1SDimitry Andric     Store->copyMetadata(SI, {LLVMContext::MD_mem_parallel_loop_access,
2993fe6060f1SDimitry Andric                              LLVMContext::MD_access_group});
29940b57cec5SDimitry Andric     if (AATags)
2995*0fca6ea1SDimitry Andric       Store->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
2996*0fca6ea1SDimitry Andric                                                   V->getType(), DL));
2997e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&SI);
29980b57cec5SDimitry Andric 
2999bdd1243dSDimitry Andric     // NOTE: Careful to use OrigV rather than V.
300006c3fb27SDimitry Andric     migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &SI,
300106c3fb27SDimitry Andric                      Store, Store->getPointerOperand(), OrigV, DL);
30020b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *Store << "\n");
30030b57cec5SDimitry Andric     return true;
30040b57cec5SDimitry Andric   }
30050b57cec5SDimitry Andric 
30060b57cec5SDimitry Andric   bool rewriteIntegerStore(Value *V, StoreInst &SI, AAMDNodes AATags) {
30070b57cec5SDimitry Andric     assert(IntTy && "We cannot extract an integer from the alloca");
30080b57cec5SDimitry Andric     assert(!SI.isVolatile());
3009bdd1243dSDimitry Andric     if (DL.getTypeSizeInBits(V->getType()).getFixedValue() !=
30105ffd83dbSDimitry Andric         IntTy->getBitWidth()) {
30110b57cec5SDimitry Andric       Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
30125ffd83dbSDimitry Andric                                          NewAI.getAlign(), "oldload");
30130b57cec5SDimitry Andric       Old = convertValue(DL, IRB, Old, IntTy);
30140b57cec5SDimitry Andric       assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
30150b57cec5SDimitry Andric       uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
30160b57cec5SDimitry Andric       V = insertInteger(DL, IRB, Old, SI.getValueOperand(), Offset, "insert");
30170b57cec5SDimitry Andric     }
30180b57cec5SDimitry Andric     V = convertValue(DL, IRB, V, NewAllocaTy);
30195ffd83dbSDimitry Andric     StoreInst *Store = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlign());
30200b57cec5SDimitry Andric     Store->copyMetadata(SI, {LLVMContext::MD_mem_parallel_loop_access,
30210b57cec5SDimitry Andric                              LLVMContext::MD_access_group});
30220b57cec5SDimitry Andric     if (AATags)
3023*0fca6ea1SDimitry Andric       Store->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
3024*0fca6ea1SDimitry Andric                                                   V->getType(), DL));
3025bdd1243dSDimitry Andric 
302606c3fb27SDimitry Andric     migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &SI,
302706c3fb27SDimitry Andric                      Store, Store->getPointerOperand(),
302806c3fb27SDimitry Andric                      Store->getValueOperand(), DL);
3029bdd1243dSDimitry Andric 
3030e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&SI);
30310b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *Store << "\n");
30320b57cec5SDimitry Andric     return true;
30330b57cec5SDimitry Andric   }
30340b57cec5SDimitry Andric 
30350b57cec5SDimitry Andric   bool visitStoreInst(StoreInst &SI) {
30360b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << SI << "\n");
30370b57cec5SDimitry Andric     Value *OldOp = SI.getOperand(1);
30380b57cec5SDimitry Andric     assert(OldOp == OldPtr);
30390b57cec5SDimitry Andric 
3040349cc55cSDimitry Andric     AAMDNodes AATags = SI.getAAMetadata();
30410b57cec5SDimitry Andric     Value *V = SI.getValueOperand();
30420b57cec5SDimitry Andric 
30430b57cec5SDimitry Andric     // Strip all inbounds GEPs and pointer casts to try to dig out any root
30440b57cec5SDimitry Andric     // alloca that should be re-examined after promoting this alloca.
30450b57cec5SDimitry Andric     if (V->getType()->isPointerTy())
30460b57cec5SDimitry Andric       if (AllocaInst *AI = dyn_cast<AllocaInst>(V->stripInBoundsOffsets()))
30470b57cec5SDimitry Andric         Pass.PostPromotionWorklist.insert(AI);
30480b57cec5SDimitry Andric 
3049bdd1243dSDimitry Andric     if (SliceSize < DL.getTypeStoreSize(V->getType()).getFixedValue()) {
30500b57cec5SDimitry Andric       assert(!SI.isVolatile());
30510b57cec5SDimitry Andric       assert(V->getType()->isIntegerTy() &&
30520b57cec5SDimitry Andric              "Only integer type loads and stores are split");
30530b57cec5SDimitry Andric       assert(DL.typeSizeEqualsStoreSize(V->getType()) &&
30540b57cec5SDimitry Andric              "Non-byte-multiple bit width");
30550b57cec5SDimitry Andric       IntegerType *NarrowTy = Type::getIntNTy(SI.getContext(), SliceSize * 8);
30560b57cec5SDimitry Andric       V = extractInteger(DL, IRB, V, NarrowTy, NewBeginOffset - BeginOffset,
30570b57cec5SDimitry Andric                          "extract");
30580b57cec5SDimitry Andric     }
30590b57cec5SDimitry Andric 
30600b57cec5SDimitry Andric     if (VecTy)
30610b57cec5SDimitry Andric       return rewriteVectorizedStoreInst(V, SI, OldOp, AATags);
30620b57cec5SDimitry Andric     if (IntTy && V->getType()->isIntegerTy())
30630b57cec5SDimitry Andric       return rewriteIntegerStore(V, SI, AATags);
30640b57cec5SDimitry Andric 
30650b57cec5SDimitry Andric     StoreInst *NewSI;
30660b57cec5SDimitry Andric     if (NewBeginOffset == NewAllocaBeginOffset &&
30670b57cec5SDimitry Andric         NewEndOffset == NewAllocaEndOffset &&
30685f757f3fSDimitry Andric         canConvertValue(DL, V->getType(), NewAllocaTy)) {
30690b57cec5SDimitry Andric       V = convertValue(DL, IRB, V, NewAllocaTy);
3070bdd1243dSDimitry Andric       Value *NewPtr =
3071bdd1243dSDimitry Andric           getPtrToNewAI(SI.getPointerAddressSpace(), SI.isVolatile());
3072bdd1243dSDimitry Andric 
30735ffd83dbSDimitry Andric       NewSI =
3074bdd1243dSDimitry Andric           IRB.CreateAlignedStore(V, NewPtr, NewAI.getAlign(), SI.isVolatile());
30750b57cec5SDimitry Andric     } else {
30760b57cec5SDimitry Andric       unsigned AS = SI.getPointerAddressSpace();
30775f757f3fSDimitry Andric       Value *NewPtr = getNewAllocaSlicePtr(IRB, IRB.getPtrTy(AS));
30785ffd83dbSDimitry Andric       NewSI =
30795ffd83dbSDimitry Andric           IRB.CreateAlignedStore(V, NewPtr, getSliceAlign(), SI.isVolatile());
30800b57cec5SDimitry Andric     }
30810b57cec5SDimitry Andric     NewSI->copyMetadata(SI, {LLVMContext::MD_mem_parallel_loop_access,
30820b57cec5SDimitry Andric                              LLVMContext::MD_access_group});
30830b57cec5SDimitry Andric     if (AATags)
3084*0fca6ea1SDimitry Andric       NewSI->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
3085*0fca6ea1SDimitry Andric                                                   V->getType(), DL));
30860b57cec5SDimitry Andric     if (SI.isVolatile())
30870b57cec5SDimitry Andric       NewSI->setAtomic(SI.getOrdering(), SI.getSyncScopeID());
30888c27c554SDimitry Andric     if (NewSI->isAtomic())
30898c27c554SDimitry Andric       NewSI->setAlignment(SI.getAlign());
3090bdd1243dSDimitry Andric 
309106c3fb27SDimitry Andric     migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &SI,
309206c3fb27SDimitry Andric                      NewSI, NewSI->getPointerOperand(),
309306c3fb27SDimitry Andric                      NewSI->getValueOperand(), DL);
3094bdd1243dSDimitry Andric 
3095e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&SI);
30960b57cec5SDimitry Andric     deleteIfTriviallyDead(OldOp);
30970b57cec5SDimitry Andric 
30980b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *NewSI << "\n");
3099349cc55cSDimitry Andric     return NewSI->getPointerOperand() == &NewAI &&
3100349cc55cSDimitry Andric            NewSI->getValueOperand()->getType() == NewAllocaTy &&
3101349cc55cSDimitry Andric            !SI.isVolatile();
31020b57cec5SDimitry Andric   }
31030b57cec5SDimitry Andric 
31040b57cec5SDimitry Andric   /// Compute an integer value from splatting an i8 across the given
31050b57cec5SDimitry Andric   /// number of bytes.
31060b57cec5SDimitry Andric   ///
31070b57cec5SDimitry Andric   /// Note that this routine assumes an i8 is a byte. If that isn't true, don't
31080b57cec5SDimitry Andric   /// call this routine.
31090b57cec5SDimitry Andric   /// FIXME: Heed the advice above.
31100b57cec5SDimitry Andric   ///
31110b57cec5SDimitry Andric   /// \param V The i8 value to splat.
31120b57cec5SDimitry Andric   /// \param Size The number of bytes in the output (assuming i8 is one byte)
31130b57cec5SDimitry Andric   Value *getIntegerSplat(Value *V, unsigned Size) {
31140b57cec5SDimitry Andric     assert(Size > 0 && "Expected a positive number of bytes.");
31150b57cec5SDimitry Andric     IntegerType *VTy = cast<IntegerType>(V->getType());
31160b57cec5SDimitry Andric     assert(VTy->getBitWidth() == 8 && "Expected an i8 value for the byte");
31170b57cec5SDimitry Andric     if (Size == 1)
31180b57cec5SDimitry Andric       return V;
31190b57cec5SDimitry Andric 
31200b57cec5SDimitry Andric     Type *SplatIntTy = Type::getIntNTy(VTy->getContext(), Size * 8);
31210b57cec5SDimitry Andric     V = IRB.CreateMul(
31220b57cec5SDimitry Andric         IRB.CreateZExt(V, SplatIntTy, "zext"),
312381ad6265SDimitry Andric         IRB.CreateUDiv(Constant::getAllOnesValue(SplatIntTy),
312481ad6265SDimitry Andric                        IRB.CreateZExt(Constant::getAllOnesValue(V->getType()),
31250b57cec5SDimitry Andric                                       SplatIntTy)),
31260b57cec5SDimitry Andric         "isplat");
31270b57cec5SDimitry Andric     return V;
31280b57cec5SDimitry Andric   }
31290b57cec5SDimitry Andric 
31300b57cec5SDimitry Andric   /// Compute a vector splat for a given element value.
31310b57cec5SDimitry Andric   Value *getVectorSplat(Value *V, unsigned NumElements) {
31320b57cec5SDimitry Andric     V = IRB.CreateVectorSplat(NumElements, V, "vsplat");
31330b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "       splat: " << *V << "\n");
31340b57cec5SDimitry Andric     return V;
31350b57cec5SDimitry Andric   }
31360b57cec5SDimitry Andric 
31370b57cec5SDimitry Andric   bool visitMemSetInst(MemSetInst &II) {
31380b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << II << "\n");
31390b57cec5SDimitry Andric     assert(II.getRawDest() == OldPtr);
31400b57cec5SDimitry Andric 
3141349cc55cSDimitry Andric     AAMDNodes AATags = II.getAAMetadata();
31420b57cec5SDimitry Andric 
31430b57cec5SDimitry Andric     // If the memset has a variable size, it cannot be split, just adjust the
31440b57cec5SDimitry Andric     // pointer to the new alloca.
3145fe6060f1SDimitry Andric     if (!isa<ConstantInt>(II.getLength())) {
31460b57cec5SDimitry Andric       assert(!IsSplit);
31470b57cec5SDimitry Andric       assert(NewBeginOffset == BeginOffset);
31480b57cec5SDimitry Andric       II.setDest(getNewAllocaSlicePtr(IRB, OldPtr->getType()));
31490b57cec5SDimitry Andric       II.setDestAlignment(getSliceAlign());
3150bdd1243dSDimitry Andric       // In theory we should call migrateDebugInfo here. However, we do not
3151bdd1243dSDimitry Andric       // emit dbg.assign intrinsics for mem intrinsics storing through non-
3152bdd1243dSDimitry Andric       // constant geps, or storing a variable number of bytes.
3153bdd1243dSDimitry Andric       assert(at::getAssignmentMarkers(&II).empty() &&
3154*0fca6ea1SDimitry Andric              at::getDVRAssignmentMarkers(&II).empty() &&
3155bdd1243dSDimitry Andric              "AT: Unexpected link to non-const GEP");
31560b57cec5SDimitry Andric       deleteIfTriviallyDead(OldPtr);
31570b57cec5SDimitry Andric       return false;
31580b57cec5SDimitry Andric     }
31590b57cec5SDimitry Andric 
31600b57cec5SDimitry Andric     // Record this instruction for deletion.
3161e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&II);
31620b57cec5SDimitry Andric 
31630b57cec5SDimitry Andric     Type *AllocaTy = NewAI.getAllocatedType();
31640b57cec5SDimitry Andric     Type *ScalarTy = AllocaTy->getScalarType();
31650b57cec5SDimitry Andric 
31660b57cec5SDimitry Andric     const bool CanContinue = [&]() {
31670b57cec5SDimitry Andric       if (VecTy || IntTy)
31680b57cec5SDimitry Andric         return true;
3169*0fca6ea1SDimitry Andric       if (BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset)
31700b57cec5SDimitry Andric         return false;
31716e75b2fbSDimitry Andric       // Length must be in range for FixedVectorType.
31720b57cec5SDimitry Andric       auto *C = cast<ConstantInt>(II.getLength());
31736e75b2fbSDimitry Andric       const uint64_t Len = C->getLimitedValue();
31746e75b2fbSDimitry Andric       if (Len > std::numeric_limits<unsigned>::max())
31750b57cec5SDimitry Andric         return false;
31760b57cec5SDimitry Andric       auto *Int8Ty = IntegerType::getInt8Ty(NewAI.getContext());
31775ffd83dbSDimitry Andric       auto *SrcTy = FixedVectorType::get(Int8Ty, Len);
31780b57cec5SDimitry Andric       return canConvertValue(DL, SrcTy, AllocaTy) &&
3179bdd1243dSDimitry Andric              DL.isLegalInteger(DL.getTypeSizeInBits(ScalarTy).getFixedValue());
31800b57cec5SDimitry Andric     }();
31810b57cec5SDimitry Andric 
31820b57cec5SDimitry Andric     // If this doesn't map cleanly onto the alloca type, and that type isn't
31830b57cec5SDimitry Andric     // a single value type, just emit a memset.
31840b57cec5SDimitry Andric     if (!CanContinue) {
31850b57cec5SDimitry Andric       Type *SizeTy = II.getLength()->getType();
3186*0fca6ea1SDimitry Andric       unsigned Sz = NewEndOffset - NewBeginOffset;
3187*0fca6ea1SDimitry Andric       Constant *Size = ConstantInt::get(SizeTy, Sz);
3188bdd1243dSDimitry Andric       MemIntrinsic *New = cast<MemIntrinsic>(IRB.CreateMemSet(
31890b57cec5SDimitry Andric           getNewAllocaSlicePtr(IRB, OldPtr->getType()), II.getValue(), Size,
3190bdd1243dSDimitry Andric           MaybeAlign(getSliceAlign()), II.isVolatile()));
31910b57cec5SDimitry Andric       if (AATags)
3192*0fca6ea1SDimitry Andric         New->setAAMetadata(
3193*0fca6ea1SDimitry Andric             AATags.adjustForAccess(NewBeginOffset - BeginOffset, Sz));
3194bdd1243dSDimitry Andric 
319506c3fb27SDimitry Andric       migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &II,
319606c3fb27SDimitry Andric                        New, New->getRawDest(), nullptr, DL);
3197bdd1243dSDimitry Andric 
31980b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          to: " << *New << "\n");
31990b57cec5SDimitry Andric       return false;
32000b57cec5SDimitry Andric     }
32010b57cec5SDimitry Andric 
32020b57cec5SDimitry Andric     // If we can represent this as a simple value, we have to build the actual
32030b57cec5SDimitry Andric     // value to store, which requires expanding the byte present in memset to
32040b57cec5SDimitry Andric     // a sensible representation for the alloca type. This is essentially
32050b57cec5SDimitry Andric     // splatting the byte to a sufficiently wide integer, splatting it across
32060b57cec5SDimitry Andric     // any desired vector width, and bitcasting to the final type.
32070b57cec5SDimitry Andric     Value *V;
32080b57cec5SDimitry Andric 
32090b57cec5SDimitry Andric     if (VecTy) {
32100b57cec5SDimitry Andric       // If this is a memset of a vectorized alloca, insert it.
32110b57cec5SDimitry Andric       assert(ElementTy == ScalarTy);
32120b57cec5SDimitry Andric 
32130b57cec5SDimitry Andric       unsigned BeginIndex = getIndex(NewBeginOffset);
32140b57cec5SDimitry Andric       unsigned EndIndex = getIndex(NewEndOffset);
32150b57cec5SDimitry Andric       assert(EndIndex > BeginIndex && "Empty vector!");
32160b57cec5SDimitry Andric       unsigned NumElements = EndIndex - BeginIndex;
32175ffd83dbSDimitry Andric       assert(NumElements <= cast<FixedVectorType>(VecTy)->getNumElements() &&
32185ffd83dbSDimitry Andric              "Too many elements!");
32190b57cec5SDimitry Andric 
32205ffd83dbSDimitry Andric       Value *Splat = getIntegerSplat(
3221bdd1243dSDimitry Andric           II.getValue(), DL.getTypeSizeInBits(ElementTy).getFixedValue() / 8);
32220b57cec5SDimitry Andric       Splat = convertValue(DL, IRB, Splat, ElementTy);
32230b57cec5SDimitry Andric       if (NumElements > 1)
32240b57cec5SDimitry Andric         Splat = getVectorSplat(Splat, NumElements);
32250b57cec5SDimitry Andric 
32260b57cec5SDimitry Andric       Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
32275ffd83dbSDimitry Andric                                          NewAI.getAlign(), "oldload");
32280b57cec5SDimitry Andric       V = insertVector(IRB, Old, Splat, BeginIndex, "vec");
32290b57cec5SDimitry Andric     } else if (IntTy) {
32300b57cec5SDimitry Andric       // If this is a memset on an alloca where we can widen stores, insert the
32310b57cec5SDimitry Andric       // set integer.
32320b57cec5SDimitry Andric       assert(!II.isVolatile());
32330b57cec5SDimitry Andric 
32340b57cec5SDimitry Andric       uint64_t Size = NewEndOffset - NewBeginOffset;
32350b57cec5SDimitry Andric       V = getIntegerSplat(II.getValue(), Size);
32360b57cec5SDimitry Andric 
32370b57cec5SDimitry Andric       if (IntTy && (BeginOffset != NewAllocaBeginOffset ||
32380b57cec5SDimitry Andric                     EndOffset != NewAllocaBeginOffset)) {
32390b57cec5SDimitry Andric         Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
32405ffd83dbSDimitry Andric                                            NewAI.getAlign(), "oldload");
32410b57cec5SDimitry Andric         Old = convertValue(DL, IRB, Old, IntTy);
32420b57cec5SDimitry Andric         uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
32430b57cec5SDimitry Andric         V = insertInteger(DL, IRB, Old, V, Offset, "insert");
32440b57cec5SDimitry Andric       } else {
32450b57cec5SDimitry Andric         assert(V->getType() == IntTy &&
32460b57cec5SDimitry Andric                "Wrong type for an alloca wide integer!");
32470b57cec5SDimitry Andric       }
32480b57cec5SDimitry Andric       V = convertValue(DL, IRB, V, AllocaTy);
32490b57cec5SDimitry Andric     } else {
32500b57cec5SDimitry Andric       // Established these invariants above.
32510b57cec5SDimitry Andric       assert(NewBeginOffset == NewAllocaBeginOffset);
32520b57cec5SDimitry Andric       assert(NewEndOffset == NewAllocaEndOffset);
32530b57cec5SDimitry Andric 
32545ffd83dbSDimitry Andric       V = getIntegerSplat(II.getValue(),
3255bdd1243dSDimitry Andric                           DL.getTypeSizeInBits(ScalarTy).getFixedValue() / 8);
32560b57cec5SDimitry Andric       if (VectorType *AllocaVecTy = dyn_cast<VectorType>(AllocaTy))
32575ffd83dbSDimitry Andric         V = getVectorSplat(
32585ffd83dbSDimitry Andric             V, cast<FixedVectorType>(AllocaVecTy)->getNumElements());
32590b57cec5SDimitry Andric 
32600b57cec5SDimitry Andric       V = convertValue(DL, IRB, V, AllocaTy);
32610b57cec5SDimitry Andric     }
32620b57cec5SDimitry Andric 
3263bdd1243dSDimitry Andric     Value *NewPtr = getPtrToNewAI(II.getDestAddressSpace(), II.isVolatile());
32645ffd83dbSDimitry Andric     StoreInst *New =
3265bdd1243dSDimitry Andric         IRB.CreateAlignedStore(V, NewPtr, NewAI.getAlign(), II.isVolatile());
3266fe6060f1SDimitry Andric     New->copyMetadata(II, {LLVMContext::MD_mem_parallel_loop_access,
3267fe6060f1SDimitry Andric                            LLVMContext::MD_access_group});
32680b57cec5SDimitry Andric     if (AATags)
3269*0fca6ea1SDimitry Andric       New->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
3270*0fca6ea1SDimitry Andric                                                 V->getType(), DL));
3271bdd1243dSDimitry Andric 
327206c3fb27SDimitry Andric     migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &II,
327306c3fb27SDimitry Andric                      New, New->getPointerOperand(), V, DL);
3274bdd1243dSDimitry Andric 
32750b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *New << "\n");
32760b57cec5SDimitry Andric     return !II.isVolatile();
32770b57cec5SDimitry Andric   }
32780b57cec5SDimitry Andric 
32790b57cec5SDimitry Andric   bool visitMemTransferInst(MemTransferInst &II) {
32800b57cec5SDimitry Andric     // Rewriting of memory transfer instructions can be a bit tricky. We break
32810b57cec5SDimitry Andric     // them into two categories: split intrinsics and unsplit intrinsics.
32820b57cec5SDimitry Andric 
32830b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << II << "\n");
32840b57cec5SDimitry Andric 
3285349cc55cSDimitry Andric     AAMDNodes AATags = II.getAAMetadata();
32860b57cec5SDimitry Andric 
32870b57cec5SDimitry Andric     bool IsDest = &II.getRawDestUse() == OldUse;
32880b57cec5SDimitry Andric     assert((IsDest && II.getRawDest() == OldPtr) ||
32890b57cec5SDimitry Andric            (!IsDest && II.getRawSource() == OldPtr));
32900b57cec5SDimitry Andric 
329181ad6265SDimitry Andric     Align SliceAlign = getSliceAlign();
32920b57cec5SDimitry Andric     // For unsplit intrinsics, we simply modify the source and destination
32930b57cec5SDimitry Andric     // pointers in place. This isn't just an optimization, it is a matter of
32940b57cec5SDimitry Andric     // correctness. With unsplit intrinsics we may be dealing with transfers
32950b57cec5SDimitry Andric     // within a single alloca before SROA ran, or with transfers that have
32960b57cec5SDimitry Andric     // a variable length. We may also be dealing with memmove instead of
32970b57cec5SDimitry Andric     // memcpy, and so simply updating the pointers is the necessary for us to
32980b57cec5SDimitry Andric     // update both source and dest of a single call.
32990b57cec5SDimitry Andric     if (!IsSplittable) {
33000b57cec5SDimitry Andric       Value *AdjustedPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
33010b57cec5SDimitry Andric       if (IsDest) {
3302bdd1243dSDimitry Andric         // Update the address component of linked dbg.assigns.
33037a6dacacSDimitry Andric         auto UpdateAssignAddress = [&](auto *DbgAssign) {
33047a6dacacSDimitry Andric           if (llvm::is_contained(DbgAssign->location_ops(), II.getDest()) ||
33057a6dacacSDimitry Andric               DbgAssign->getAddress() == II.getDest())
33067a6dacacSDimitry Andric             DbgAssign->replaceVariableLocationOp(II.getDest(), AdjustedPtr);
33077a6dacacSDimitry Andric         };
33087a6dacacSDimitry Andric         for_each(at::getAssignmentMarkers(&II), UpdateAssignAddress);
3309*0fca6ea1SDimitry Andric         for_each(at::getDVRAssignmentMarkers(&II), UpdateAssignAddress);
33100b57cec5SDimitry Andric         II.setDest(AdjustedPtr);
33110b57cec5SDimitry Andric         II.setDestAlignment(SliceAlign);
3312bdd1243dSDimitry Andric       } else {
33130b57cec5SDimitry Andric         II.setSource(AdjustedPtr);
33140b57cec5SDimitry Andric         II.setSourceAlignment(SliceAlign);
33150b57cec5SDimitry Andric       }
33160b57cec5SDimitry Andric 
33170b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          to: " << II << "\n");
33180b57cec5SDimitry Andric       deleteIfTriviallyDead(OldPtr);
33190b57cec5SDimitry Andric       return false;
33200b57cec5SDimitry Andric     }
33210b57cec5SDimitry Andric     // For split transfer intrinsics we have an incredibly useful assurance:
33220b57cec5SDimitry Andric     // the source and destination do not reside within the same alloca, and at
33230b57cec5SDimitry Andric     // least one of them does not escape. This means that we can replace
33240b57cec5SDimitry Andric     // memmove with memcpy, and we don't need to worry about all manner of
33250b57cec5SDimitry Andric     // downsides to splitting and transforming the operations.
33260b57cec5SDimitry Andric 
33270b57cec5SDimitry Andric     // If this doesn't map cleanly onto the alloca type, and that type isn't
33280b57cec5SDimitry Andric     // a single value type, just emit a memcpy.
33290b57cec5SDimitry Andric     bool EmitMemCpy =
33300b57cec5SDimitry Andric         !VecTy && !IntTy &&
33310b57cec5SDimitry Andric         (BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset ||
33325ffd83dbSDimitry Andric          SliceSize !=
3333bdd1243dSDimitry Andric              DL.getTypeStoreSize(NewAI.getAllocatedType()).getFixedValue() ||
3334cb14a3feSDimitry Andric          !DL.typeSizeEqualsStoreSize(NewAI.getAllocatedType()) ||
33350b57cec5SDimitry Andric          !NewAI.getAllocatedType()->isSingleValueType());
33360b57cec5SDimitry Andric 
33370b57cec5SDimitry Andric     // If we're just going to emit a memcpy, the alloca hasn't changed, and the
33380b57cec5SDimitry Andric     // size hasn't been shrunk based on analysis of the viable range, this is
33390b57cec5SDimitry Andric     // a no-op.
33400b57cec5SDimitry Andric     if (EmitMemCpy && &OldAI == &NewAI) {
33410b57cec5SDimitry Andric       // Ensure the start lines up.
33420b57cec5SDimitry Andric       assert(NewBeginOffset == BeginOffset);
33430b57cec5SDimitry Andric 
33440b57cec5SDimitry Andric       // Rewrite the size as needed.
33450b57cec5SDimitry Andric       if (NewEndOffset != EndOffset)
33460b57cec5SDimitry Andric         II.setLength(ConstantInt::get(II.getLength()->getType(),
33470b57cec5SDimitry Andric                                       NewEndOffset - NewBeginOffset));
33480b57cec5SDimitry Andric       return false;
33490b57cec5SDimitry Andric     }
33500b57cec5SDimitry Andric     // Record this instruction for deletion.
3351e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&II);
33520b57cec5SDimitry Andric 
33530b57cec5SDimitry Andric     // Strip all inbounds GEPs and pointer casts to try to dig out any root
33540b57cec5SDimitry Andric     // alloca that should be re-examined after rewriting this instruction.
33550b57cec5SDimitry Andric     Value *OtherPtr = IsDest ? II.getRawSource() : II.getRawDest();
33560b57cec5SDimitry Andric     if (AllocaInst *AI =
33570b57cec5SDimitry Andric             dyn_cast<AllocaInst>(OtherPtr->stripInBoundsOffsets())) {
33580b57cec5SDimitry Andric       assert(AI != &OldAI && AI != &NewAI &&
33590b57cec5SDimitry Andric              "Splittable transfers cannot reach the same alloca on both ends.");
33600b57cec5SDimitry Andric       Pass.Worklist.insert(AI);
33610b57cec5SDimitry Andric     }
33620b57cec5SDimitry Andric 
33630b57cec5SDimitry Andric     Type *OtherPtrTy = OtherPtr->getType();
33640b57cec5SDimitry Andric     unsigned OtherAS = OtherPtrTy->getPointerAddressSpace();
33650b57cec5SDimitry Andric 
33660b57cec5SDimitry Andric     // Compute the relative offset for the other pointer within the transfer.
33670b57cec5SDimitry Andric     unsigned OffsetWidth = DL.getIndexSizeInBits(OtherAS);
33680b57cec5SDimitry Andric     APInt OtherOffset(OffsetWidth, NewBeginOffset - BeginOffset);
3369480093f4SDimitry Andric     Align OtherAlign =
33705ffd83dbSDimitry Andric         (IsDest ? II.getSourceAlign() : II.getDestAlign()).valueOrOne();
3371480093f4SDimitry Andric     OtherAlign =
3372480093f4SDimitry Andric         commonAlignment(OtherAlign, OtherOffset.zextOrTrunc(64).getZExtValue());
33730b57cec5SDimitry Andric 
33740b57cec5SDimitry Andric     if (EmitMemCpy) {
33750b57cec5SDimitry Andric       // Compute the other pointer, folding as much as possible to produce
33760b57cec5SDimitry Andric       // a single, simple GEP in most cases.
33770b57cec5SDimitry Andric       OtherPtr = getAdjustedPtr(IRB, DL, OtherPtr, OtherOffset, OtherPtrTy,
33780b57cec5SDimitry Andric                                 OtherPtr->getName() + ".");
33790b57cec5SDimitry Andric 
33800b57cec5SDimitry Andric       Value *OurPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
33810b57cec5SDimitry Andric       Type *SizeTy = II.getLength()->getType();
33820b57cec5SDimitry Andric       Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
33830b57cec5SDimitry Andric 
33840b57cec5SDimitry Andric       Value *DestPtr, *SrcPtr;
3385480093f4SDimitry Andric       MaybeAlign DestAlign, SrcAlign;
33860b57cec5SDimitry Andric       // Note: IsDest is true iff we're copying into the new alloca slice
33870b57cec5SDimitry Andric       if (IsDest) {
33880b57cec5SDimitry Andric         DestPtr = OurPtr;
33890b57cec5SDimitry Andric         DestAlign = SliceAlign;
33900b57cec5SDimitry Andric         SrcPtr = OtherPtr;
33910b57cec5SDimitry Andric         SrcAlign = OtherAlign;
33920b57cec5SDimitry Andric       } else {
33930b57cec5SDimitry Andric         DestPtr = OtherPtr;
33940b57cec5SDimitry Andric         DestAlign = OtherAlign;
33950b57cec5SDimitry Andric         SrcPtr = OurPtr;
33960b57cec5SDimitry Andric         SrcAlign = SliceAlign;
33970b57cec5SDimitry Andric       }
33980b57cec5SDimitry Andric       CallInst *New = IRB.CreateMemCpy(DestPtr, DestAlign, SrcPtr, SrcAlign,
33990b57cec5SDimitry Andric                                        Size, II.isVolatile());
34000b57cec5SDimitry Andric       if (AATags)
3401d409305fSDimitry Andric         New->setAAMetadata(AATags.shift(NewBeginOffset - BeginOffset));
3402bdd1243dSDimitry Andric 
340306c3fb27SDimitry Andric       APInt Offset(DL.getIndexTypeSizeInBits(DestPtr->getType()), 0);
340406c3fb27SDimitry Andric       if (IsDest) {
340506c3fb27SDimitry Andric         migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8,
340606c3fb27SDimitry Andric                          &II, New, DestPtr, nullptr, DL);
340706c3fb27SDimitry Andric       } else if (AllocaInst *Base = dyn_cast<AllocaInst>(
340806c3fb27SDimitry Andric                      DestPtr->stripAndAccumulateConstantOffsets(
340906c3fb27SDimitry Andric                          DL, Offset, /*AllowNonInbounds*/ true))) {
341006c3fb27SDimitry Andric         migrateDebugInfo(Base, IsSplit, Offset.getZExtValue() * 8,
341106c3fb27SDimitry Andric                          SliceSize * 8, &II, New, DestPtr, nullptr, DL);
341206c3fb27SDimitry Andric       }
34130b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          to: " << *New << "\n");
34140b57cec5SDimitry Andric       return false;
34150b57cec5SDimitry Andric     }
34160b57cec5SDimitry Andric 
34170b57cec5SDimitry Andric     bool IsWholeAlloca = NewBeginOffset == NewAllocaBeginOffset &&
34180b57cec5SDimitry Andric                          NewEndOffset == NewAllocaEndOffset;
34190b57cec5SDimitry Andric     uint64_t Size = NewEndOffset - NewBeginOffset;
34200b57cec5SDimitry Andric     unsigned BeginIndex = VecTy ? getIndex(NewBeginOffset) : 0;
34210b57cec5SDimitry Andric     unsigned EndIndex = VecTy ? getIndex(NewEndOffset) : 0;
34220b57cec5SDimitry Andric     unsigned NumElements = EndIndex - BeginIndex;
34230b57cec5SDimitry Andric     IntegerType *SubIntTy =
34240b57cec5SDimitry Andric         IntTy ? Type::getIntNTy(IntTy->getContext(), Size * 8) : nullptr;
34250b57cec5SDimitry Andric 
34260b57cec5SDimitry Andric     // Reset the other pointer type to match the register type we're going to
34270b57cec5SDimitry Andric     // use, but using the address space of the original other pointer.
34280b57cec5SDimitry Andric     Type *OtherTy;
34290b57cec5SDimitry Andric     if (VecTy && !IsWholeAlloca) {
34300b57cec5SDimitry Andric       if (NumElements == 1)
34310b57cec5SDimitry Andric         OtherTy = VecTy->getElementType();
34320b57cec5SDimitry Andric       else
34335ffd83dbSDimitry Andric         OtherTy = FixedVectorType::get(VecTy->getElementType(), NumElements);
34340b57cec5SDimitry Andric     } else if (IntTy && !IsWholeAlloca) {
34350b57cec5SDimitry Andric       OtherTy = SubIntTy;
34360b57cec5SDimitry Andric     } else {
34370b57cec5SDimitry Andric       OtherTy = NewAllocaTy;
34380b57cec5SDimitry Andric     }
34390b57cec5SDimitry Andric 
3440bdd1243dSDimitry Andric     Value *AdjPtr = getAdjustedPtr(IRB, DL, OtherPtr, OtherOffset, OtherPtrTy,
34410b57cec5SDimitry Andric                                    OtherPtr->getName() + ".");
3442480093f4SDimitry Andric     MaybeAlign SrcAlign = OtherAlign;
3443480093f4SDimitry Andric     MaybeAlign DstAlign = SliceAlign;
3444bdd1243dSDimitry Andric     if (!IsDest)
34450b57cec5SDimitry Andric       std::swap(SrcAlign, DstAlign);
3446bdd1243dSDimitry Andric 
3447bdd1243dSDimitry Andric     Value *SrcPtr;
3448bdd1243dSDimitry Andric     Value *DstPtr;
3449bdd1243dSDimitry Andric 
3450bdd1243dSDimitry Andric     if (IsDest) {
3451bdd1243dSDimitry Andric       DstPtr = getPtrToNewAI(II.getDestAddressSpace(), II.isVolatile());
3452bdd1243dSDimitry Andric       SrcPtr = AdjPtr;
3453bdd1243dSDimitry Andric     } else {
3454bdd1243dSDimitry Andric       DstPtr = AdjPtr;
3455bdd1243dSDimitry Andric       SrcPtr = getPtrToNewAI(II.getSourceAddressSpace(), II.isVolatile());
34560b57cec5SDimitry Andric     }
34570b57cec5SDimitry Andric 
34580b57cec5SDimitry Andric     Value *Src;
34590b57cec5SDimitry Andric     if (VecTy && !IsWholeAlloca && !IsDest) {
34600b57cec5SDimitry Andric       Src = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
34615ffd83dbSDimitry Andric                                   NewAI.getAlign(), "load");
34620b57cec5SDimitry Andric       Src = extractVector(IRB, Src, BeginIndex, EndIndex, "vec");
34630b57cec5SDimitry Andric     } else if (IntTy && !IsWholeAlloca && !IsDest) {
34640b57cec5SDimitry Andric       Src = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
34655ffd83dbSDimitry Andric                                   NewAI.getAlign(), "load");
34660b57cec5SDimitry Andric       Src = convertValue(DL, IRB, Src, IntTy);
34670b57cec5SDimitry Andric       uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
34680b57cec5SDimitry Andric       Src = extractInteger(DL, IRB, Src, SubIntTy, Offset, "extract");
34690b57cec5SDimitry Andric     } else {
34700b57cec5SDimitry Andric       LoadInst *Load = IRB.CreateAlignedLoad(OtherTy, SrcPtr, SrcAlign,
34710b57cec5SDimitry Andric                                              II.isVolatile(), "copyload");
3472fe6060f1SDimitry Andric       Load->copyMetadata(II, {LLVMContext::MD_mem_parallel_loop_access,
3473fe6060f1SDimitry Andric                               LLVMContext::MD_access_group});
34740b57cec5SDimitry Andric       if (AATags)
3475*0fca6ea1SDimitry Andric         Load->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
3476*0fca6ea1SDimitry Andric                                                    Load->getType(), DL));
34770b57cec5SDimitry Andric       Src = Load;
34780b57cec5SDimitry Andric     }
34790b57cec5SDimitry Andric 
34800b57cec5SDimitry Andric     if (VecTy && !IsWholeAlloca && IsDest) {
34810b57cec5SDimitry Andric       Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
34825ffd83dbSDimitry Andric                                          NewAI.getAlign(), "oldload");
34830b57cec5SDimitry Andric       Src = insertVector(IRB, Old, Src, BeginIndex, "vec");
34840b57cec5SDimitry Andric     } else if (IntTy && !IsWholeAlloca && IsDest) {
34850b57cec5SDimitry Andric       Value *Old = IRB.CreateAlignedLoad(NewAI.getAllocatedType(), &NewAI,
34865ffd83dbSDimitry Andric                                          NewAI.getAlign(), "oldload");
34870b57cec5SDimitry Andric       Old = convertValue(DL, IRB, Old, IntTy);
34880b57cec5SDimitry Andric       uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
34890b57cec5SDimitry Andric       Src = insertInteger(DL, IRB, Old, Src, Offset, "insert");
34900b57cec5SDimitry Andric       Src = convertValue(DL, IRB, Src, NewAllocaTy);
34910b57cec5SDimitry Andric     }
34920b57cec5SDimitry Andric 
34930b57cec5SDimitry Andric     StoreInst *Store = cast<StoreInst>(
34940b57cec5SDimitry Andric         IRB.CreateAlignedStore(Src, DstPtr, DstAlign, II.isVolatile()));
3495fe6060f1SDimitry Andric     Store->copyMetadata(II, {LLVMContext::MD_mem_parallel_loop_access,
3496fe6060f1SDimitry Andric                              LLVMContext::MD_access_group});
34970b57cec5SDimitry Andric     if (AATags)
3498*0fca6ea1SDimitry Andric       Store->setAAMetadata(AATags.adjustForAccess(NewBeginOffset - BeginOffset,
3499*0fca6ea1SDimitry Andric                                                   Src->getType(), DL));
3500bdd1243dSDimitry Andric 
350106c3fb27SDimitry Andric     APInt Offset(DL.getIndexTypeSizeInBits(DstPtr->getType()), 0);
350206c3fb27SDimitry Andric     if (IsDest) {
350306c3fb27SDimitry Andric 
350406c3fb27SDimitry Andric       migrateDebugInfo(&OldAI, IsSplit, NewBeginOffset * 8, SliceSize * 8, &II,
350506c3fb27SDimitry Andric                        Store, DstPtr, Src, DL);
350606c3fb27SDimitry Andric     } else if (AllocaInst *Base = dyn_cast<AllocaInst>(
350706c3fb27SDimitry Andric                    DstPtr->stripAndAccumulateConstantOffsets(
350806c3fb27SDimitry Andric                        DL, Offset, /*AllowNonInbounds*/ true))) {
350906c3fb27SDimitry Andric       migrateDebugInfo(Base, IsSplit, Offset.getZExtValue() * 8, SliceSize * 8,
351006c3fb27SDimitry Andric                        &II, Store, DstPtr, Src, DL);
351106c3fb27SDimitry Andric     }
351206c3fb27SDimitry Andric 
35130b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *Store << "\n");
35140b57cec5SDimitry Andric     return !II.isVolatile();
35150b57cec5SDimitry Andric   }
35160b57cec5SDimitry Andric 
35170b57cec5SDimitry Andric   bool visitIntrinsicInst(IntrinsicInst &II) {
35185f757f3fSDimitry Andric     assert((II.isLifetimeStartOrEnd() || II.isLaunderOrStripInvariantGroup() ||
35195f757f3fSDimitry Andric             II.isDroppable()) &&
3520e8d8bef9SDimitry Andric            "Unexpected intrinsic!");
35210b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << II << "\n");
35220b57cec5SDimitry Andric 
35230b57cec5SDimitry Andric     // Record this instruction for deletion.
3524e8d8bef9SDimitry Andric     Pass.DeadInsts.push_back(&II);
35250b57cec5SDimitry Andric 
3526e8d8bef9SDimitry Andric     if (II.isDroppable()) {
3527e8d8bef9SDimitry Andric       assert(II.getIntrinsicID() == Intrinsic::assume && "Expected assume");
3528e8d8bef9SDimitry Andric       // TODO For now we forget assumed information, this can be improved.
3529e8d8bef9SDimitry Andric       OldPtr->dropDroppableUsesIn(II);
3530e8d8bef9SDimitry Andric       return true;
3531e8d8bef9SDimitry Andric     }
3532e8d8bef9SDimitry Andric 
35335f757f3fSDimitry Andric     if (II.isLaunderOrStripInvariantGroup())
35345f757f3fSDimitry Andric       return true;
35355f757f3fSDimitry Andric 
3536e8d8bef9SDimitry Andric     assert(II.getArgOperand(1) == OldPtr);
35370b57cec5SDimitry Andric     // Lifetime intrinsics are only promotable if they cover the whole alloca.
35380b57cec5SDimitry Andric     // Therefore, we drop lifetime intrinsics which don't cover the whole
35390b57cec5SDimitry Andric     // alloca.
35400b57cec5SDimitry Andric     // (In theory, intrinsics which partially cover an alloca could be
35410b57cec5SDimitry Andric     // promoted, but PromoteMemToReg doesn't handle that case.)
35420b57cec5SDimitry Andric     // FIXME: Check whether the alloca is promotable before dropping the
35430b57cec5SDimitry Andric     // lifetime intrinsics?
35440b57cec5SDimitry Andric     if (NewBeginOffset != NewAllocaBeginOffset ||
35450b57cec5SDimitry Andric         NewEndOffset != NewAllocaEndOffset)
35460b57cec5SDimitry Andric       return true;
35470b57cec5SDimitry Andric 
35480b57cec5SDimitry Andric     ConstantInt *Size =
35490b57cec5SDimitry Andric         ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
35500b57cec5SDimitry Andric                          NewEndOffset - NewBeginOffset);
35510b57cec5SDimitry Andric     // Lifetime intrinsics always expect an i8* so directly get such a pointer
35520b57cec5SDimitry Andric     // for the new alloca slice.
35535f757f3fSDimitry Andric     Type *PointerTy = IRB.getPtrTy(OldPtr->getType()->getPointerAddressSpace());
35540b57cec5SDimitry Andric     Value *Ptr = getNewAllocaSlicePtr(IRB, PointerTy);
35550b57cec5SDimitry Andric     Value *New;
35560b57cec5SDimitry Andric     if (II.getIntrinsicID() == Intrinsic::lifetime_start)
35570b57cec5SDimitry Andric       New = IRB.CreateLifetimeStart(Ptr, Size);
35580b57cec5SDimitry Andric     else
35590b57cec5SDimitry Andric       New = IRB.CreateLifetimeEnd(Ptr, Size);
35600b57cec5SDimitry Andric 
35610b57cec5SDimitry Andric     (void)New;
35620b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *New << "\n");
35630b57cec5SDimitry Andric 
35640b57cec5SDimitry Andric     return true;
35650b57cec5SDimitry Andric   }
35660b57cec5SDimitry Andric 
35670b57cec5SDimitry Andric   void fixLoadStoreAlign(Instruction &Root) {
35680b57cec5SDimitry Andric     // This algorithm implements the same visitor loop as
35690b57cec5SDimitry Andric     // hasUnsafePHIOrSelectUse, and fixes the alignment of each load
35700b57cec5SDimitry Andric     // or store found.
35710b57cec5SDimitry Andric     SmallPtrSet<Instruction *, 4> Visited;
35720b57cec5SDimitry Andric     SmallVector<Instruction *, 4> Uses;
35730b57cec5SDimitry Andric     Visited.insert(&Root);
35740b57cec5SDimitry Andric     Uses.push_back(&Root);
35750b57cec5SDimitry Andric     do {
35760b57cec5SDimitry Andric       Instruction *I = Uses.pop_back_val();
35770b57cec5SDimitry Andric 
35780b57cec5SDimitry Andric       if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
35795ffd83dbSDimitry Andric         LI->setAlignment(std::min(LI->getAlign(), getSliceAlign()));
35800b57cec5SDimitry Andric         continue;
35810b57cec5SDimitry Andric       }
35820b57cec5SDimitry Andric       if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
35835ffd83dbSDimitry Andric         SI->setAlignment(std::min(SI->getAlign(), getSliceAlign()));
35840b57cec5SDimitry Andric         continue;
35850b57cec5SDimitry Andric       }
35860b57cec5SDimitry Andric 
35870b57cec5SDimitry Andric       assert(isa<BitCastInst>(I) || isa<AddrSpaceCastInst>(I) ||
35880b57cec5SDimitry Andric              isa<PHINode>(I) || isa<SelectInst>(I) ||
35890b57cec5SDimitry Andric              isa<GetElementPtrInst>(I));
35900b57cec5SDimitry Andric       for (User *U : I->users())
35910b57cec5SDimitry Andric         if (Visited.insert(cast<Instruction>(U)).second)
35920b57cec5SDimitry Andric           Uses.push_back(cast<Instruction>(U));
35930b57cec5SDimitry Andric     } while (!Uses.empty());
35940b57cec5SDimitry Andric   }
35950b57cec5SDimitry Andric 
35960b57cec5SDimitry Andric   bool visitPHINode(PHINode &PN) {
35970b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << PN << "\n");
35980b57cec5SDimitry Andric     assert(BeginOffset >= NewAllocaBeginOffset && "PHIs are unsplittable");
35990b57cec5SDimitry Andric     assert(EndOffset <= NewAllocaEndOffset && "PHIs are unsplittable");
36000b57cec5SDimitry Andric 
36010b57cec5SDimitry Andric     // We would like to compute a new pointer in only one place, but have it be
36020b57cec5SDimitry Andric     // as local as possible to the PHI. To do that, we re-use the location of
36030b57cec5SDimitry Andric     // the old pointer, which necessarily must be in the right position to
36040b57cec5SDimitry Andric     // dominate the PHI.
36055ffd83dbSDimitry Andric     IRBuilderBase::InsertPointGuard Guard(IRB);
36060b57cec5SDimitry Andric     if (isa<PHINode>(OldPtr))
36075f757f3fSDimitry Andric       IRB.SetInsertPoint(OldPtr->getParent(),
36085f757f3fSDimitry Andric                          OldPtr->getParent()->getFirstInsertionPt());
36090b57cec5SDimitry Andric     else
36105ffd83dbSDimitry Andric       IRB.SetInsertPoint(OldPtr);
36115ffd83dbSDimitry Andric     IRB.SetCurrentDebugLocation(OldPtr->getDebugLoc());
36120b57cec5SDimitry Andric 
36135ffd83dbSDimitry Andric     Value *NewPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
36140b57cec5SDimitry Andric     // Replace the operands which were using the old pointer.
36150b57cec5SDimitry Andric     std::replace(PN.op_begin(), PN.op_end(), cast<Value>(OldPtr), NewPtr);
36160b57cec5SDimitry Andric 
36170b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << PN << "\n");
36180b57cec5SDimitry Andric     deleteIfTriviallyDead(OldPtr);
36190b57cec5SDimitry Andric 
36200b57cec5SDimitry Andric     // Fix the alignment of any loads or stores using this PHI node.
36210b57cec5SDimitry Andric     fixLoadStoreAlign(PN);
36220b57cec5SDimitry Andric 
36230b57cec5SDimitry Andric     // PHIs can't be promoted on their own, but often can be speculated. We
36240b57cec5SDimitry Andric     // check the speculation outside of the rewriter so that we see the
36250b57cec5SDimitry Andric     // fully-rewritten alloca.
36260b57cec5SDimitry Andric     PHIUsers.insert(&PN);
36270b57cec5SDimitry Andric     return true;
36280b57cec5SDimitry Andric   }
36290b57cec5SDimitry Andric 
36300b57cec5SDimitry Andric   bool visitSelectInst(SelectInst &SI) {
36310b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << SI << "\n");
36320b57cec5SDimitry Andric     assert((SI.getTrueValue() == OldPtr || SI.getFalseValue() == OldPtr) &&
36330b57cec5SDimitry Andric            "Pointer isn't an operand!");
36340b57cec5SDimitry Andric     assert(BeginOffset >= NewAllocaBeginOffset && "Selects are unsplittable");
36350b57cec5SDimitry Andric     assert(EndOffset <= NewAllocaEndOffset && "Selects are unsplittable");
36360b57cec5SDimitry Andric 
36370b57cec5SDimitry Andric     Value *NewPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
36380b57cec5SDimitry Andric     // Replace the operands which were using the old pointer.
36390b57cec5SDimitry Andric     if (SI.getOperand(1) == OldPtr)
36400b57cec5SDimitry Andric       SI.setOperand(1, NewPtr);
36410b57cec5SDimitry Andric     if (SI.getOperand(2) == OldPtr)
36420b57cec5SDimitry Andric       SI.setOperand(2, NewPtr);
36430b57cec5SDimitry Andric 
36440b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << SI << "\n");
36450b57cec5SDimitry Andric     deleteIfTriviallyDead(OldPtr);
36460b57cec5SDimitry Andric 
36470b57cec5SDimitry Andric     // Fix the alignment of any loads or stores using this select.
36480b57cec5SDimitry Andric     fixLoadStoreAlign(SI);
36490b57cec5SDimitry Andric 
36500b57cec5SDimitry Andric     // Selects can't be promoted on their own, but often can be speculated. We
36510b57cec5SDimitry Andric     // check the speculation outside of the rewriter so that we see the
36520b57cec5SDimitry Andric     // fully-rewritten alloca.
36530b57cec5SDimitry Andric     SelectUsers.insert(&SI);
36540b57cec5SDimitry Andric     return true;
36550b57cec5SDimitry Andric   }
36560b57cec5SDimitry Andric };
36570b57cec5SDimitry Andric 
36580b57cec5SDimitry Andric /// Visitor to rewrite aggregate loads and stores as scalar.
36590b57cec5SDimitry Andric ///
36600b57cec5SDimitry Andric /// This pass aggressively rewrites all aggregate loads and stores on
36610b57cec5SDimitry Andric /// a particular pointer (or any pointer derived from it which we can identify)
36620b57cec5SDimitry Andric /// with scalar loads and stores.
36630b57cec5SDimitry Andric class AggLoadStoreRewriter : public InstVisitor<AggLoadStoreRewriter, bool> {
36640b57cec5SDimitry Andric   // Befriend the base class so it can delegate to private visit methods.
36650b57cec5SDimitry Andric   friend class InstVisitor<AggLoadStoreRewriter, bool>;
36660b57cec5SDimitry Andric 
36670b57cec5SDimitry Andric   /// Queue of pointer uses to analyze and potentially rewrite.
36680b57cec5SDimitry Andric   SmallVector<Use *, 8> Queue;
36690b57cec5SDimitry Andric 
36700b57cec5SDimitry Andric   /// Set to prevent us from cycling with phi nodes and loops.
36710b57cec5SDimitry Andric   SmallPtrSet<User *, 8> Visited;
36720b57cec5SDimitry Andric 
36730b57cec5SDimitry Andric   /// The current pointer use being rewritten. This is used to dig up the used
36740b57cec5SDimitry Andric   /// value (as opposed to the user).
3675480093f4SDimitry Andric   Use *U = nullptr;
36760b57cec5SDimitry Andric 
36770b57cec5SDimitry Andric   /// Used to calculate offsets, and hence alignment, of subobjects.
36780b57cec5SDimitry Andric   const DataLayout &DL;
36790b57cec5SDimitry Andric 
368004eeddc0SDimitry Andric   IRBuilderTy &IRB;
368104eeddc0SDimitry Andric 
36820b57cec5SDimitry Andric public:
368304eeddc0SDimitry Andric   AggLoadStoreRewriter(const DataLayout &DL, IRBuilderTy &IRB)
368404eeddc0SDimitry Andric       : DL(DL), IRB(IRB) {}
36850b57cec5SDimitry Andric 
36860b57cec5SDimitry Andric   /// Rewrite loads and stores through a pointer and all pointers derived from
36870b57cec5SDimitry Andric   /// it.
36880b57cec5SDimitry Andric   bool rewrite(Instruction &I) {
36890b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "  Rewriting FCA loads and stores...\n");
36900b57cec5SDimitry Andric     enqueueUsers(I);
36910b57cec5SDimitry Andric     bool Changed = false;
36920b57cec5SDimitry Andric     while (!Queue.empty()) {
36930b57cec5SDimitry Andric       U = Queue.pop_back_val();
36940b57cec5SDimitry Andric       Changed |= visit(cast<Instruction>(U->getUser()));
36950b57cec5SDimitry Andric     }
36960b57cec5SDimitry Andric     return Changed;
36970b57cec5SDimitry Andric   }
36980b57cec5SDimitry Andric 
36990b57cec5SDimitry Andric private:
37000b57cec5SDimitry Andric   /// Enqueue all the users of the given instruction for further processing.
37010b57cec5SDimitry Andric   /// This uses a set to de-duplicate users.
37020b57cec5SDimitry Andric   void enqueueUsers(Instruction &I) {
37030b57cec5SDimitry Andric     for (Use &U : I.uses())
37040b57cec5SDimitry Andric       if (Visited.insert(U.getUser()).second)
37050b57cec5SDimitry Andric         Queue.push_back(&U);
37060b57cec5SDimitry Andric   }
37070b57cec5SDimitry Andric 
37080b57cec5SDimitry Andric   // Conservative default is to not rewrite anything.
37090b57cec5SDimitry Andric   bool visitInstruction(Instruction &I) { return false; }
37100b57cec5SDimitry Andric 
37110b57cec5SDimitry Andric   /// Generic recursive split emission class.
37120b57cec5SDimitry Andric   template <typename Derived> class OpSplitter {
37130b57cec5SDimitry Andric   protected:
37140b57cec5SDimitry Andric     /// The builder used to form new instructions.
371504eeddc0SDimitry Andric     IRBuilderTy &IRB;
37160b57cec5SDimitry Andric 
37170b57cec5SDimitry Andric     /// The indices which to be used with insert- or extractvalue to select the
37180b57cec5SDimitry Andric     /// appropriate value within the aggregate.
37190b57cec5SDimitry Andric     SmallVector<unsigned, 4> Indices;
37200b57cec5SDimitry Andric 
37210b57cec5SDimitry Andric     /// The indices to a GEP instruction which will move Ptr to the correct slot
37220b57cec5SDimitry Andric     /// within the aggregate.
37230b57cec5SDimitry Andric     SmallVector<Value *, 4> GEPIndices;
37240b57cec5SDimitry Andric 
37250b57cec5SDimitry Andric     /// The base pointer of the original op, used as a base for GEPing the
37260b57cec5SDimitry Andric     /// split operations.
37270b57cec5SDimitry Andric     Value *Ptr;
37280b57cec5SDimitry Andric 
37290b57cec5SDimitry Andric     /// The base pointee type being GEPed into.
37300b57cec5SDimitry Andric     Type *BaseTy;
37310b57cec5SDimitry Andric 
37320b57cec5SDimitry Andric     /// Known alignment of the base pointer.
3733480093f4SDimitry Andric     Align BaseAlign;
37340b57cec5SDimitry Andric 
37350b57cec5SDimitry Andric     /// To calculate offset of each component so we can correctly deduce
37360b57cec5SDimitry Andric     /// alignments.
37370b57cec5SDimitry Andric     const DataLayout &DL;
37380b57cec5SDimitry Andric 
37390b57cec5SDimitry Andric     /// Initialize the splitter with an insertion point, Ptr and start with a
37400b57cec5SDimitry Andric     /// single zero GEP index.
37410b57cec5SDimitry Andric     OpSplitter(Instruction *InsertionPoint, Value *Ptr, Type *BaseTy,
374204eeddc0SDimitry Andric                Align BaseAlign, const DataLayout &DL, IRBuilderTy &IRB)
374304eeddc0SDimitry Andric         : IRB(IRB), GEPIndices(1, IRB.getInt32(0)), Ptr(Ptr), BaseTy(BaseTy),
374404eeddc0SDimitry Andric           BaseAlign(BaseAlign), DL(DL) {
374504eeddc0SDimitry Andric       IRB.SetInsertPoint(InsertionPoint);
374604eeddc0SDimitry Andric     }
37470b57cec5SDimitry Andric 
37480b57cec5SDimitry Andric   public:
37490b57cec5SDimitry Andric     /// Generic recursive split emission routine.
37500b57cec5SDimitry Andric     ///
37510b57cec5SDimitry Andric     /// This method recursively splits an aggregate op (load or store) into
37520b57cec5SDimitry Andric     /// scalar or vector ops. It splits recursively until it hits a single value
37530b57cec5SDimitry Andric     /// and emits that single value operation via the template argument.
37540b57cec5SDimitry Andric     ///
37550b57cec5SDimitry Andric     /// The logic of this routine relies on GEPs and insertvalue and
37560b57cec5SDimitry Andric     /// extractvalue all operating with the same fundamental index list, merely
37570b57cec5SDimitry Andric     /// formatted differently (GEPs need actual values).
37580b57cec5SDimitry Andric     ///
37590b57cec5SDimitry Andric     /// \param Ty  The type being split recursively into smaller ops.
37600b57cec5SDimitry Andric     /// \param Agg The aggregate value being built up or stored, depending on
37610b57cec5SDimitry Andric     /// whether this is splitting a load or a store respectively.
37620b57cec5SDimitry Andric     void emitSplitOps(Type *Ty, Value *&Agg, const Twine &Name) {
37630b57cec5SDimitry Andric       if (Ty->isSingleValueType()) {
37640b57cec5SDimitry Andric         unsigned Offset = DL.getIndexedOffsetInType(BaseTy, GEPIndices);
37650b57cec5SDimitry Andric         return static_cast<Derived *>(this)->emitFunc(
3766480093f4SDimitry Andric             Ty, Agg, commonAlignment(BaseAlign, Offset), Name);
37670b57cec5SDimitry Andric       }
37680b57cec5SDimitry Andric 
37690b57cec5SDimitry Andric       if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
37700b57cec5SDimitry Andric         unsigned OldSize = Indices.size();
37710b57cec5SDimitry Andric         (void)OldSize;
37720b57cec5SDimitry Andric         for (unsigned Idx = 0, Size = ATy->getNumElements(); Idx != Size;
37730b57cec5SDimitry Andric              ++Idx) {
37740b57cec5SDimitry Andric           assert(Indices.size() == OldSize && "Did not return to the old size");
37750b57cec5SDimitry Andric           Indices.push_back(Idx);
37760b57cec5SDimitry Andric           GEPIndices.push_back(IRB.getInt32(Idx));
37770b57cec5SDimitry Andric           emitSplitOps(ATy->getElementType(), Agg, Name + "." + Twine(Idx));
37780b57cec5SDimitry Andric           GEPIndices.pop_back();
37790b57cec5SDimitry Andric           Indices.pop_back();
37800b57cec5SDimitry Andric         }
37810b57cec5SDimitry Andric         return;
37820b57cec5SDimitry Andric       }
37830b57cec5SDimitry Andric 
37840b57cec5SDimitry Andric       if (StructType *STy = dyn_cast<StructType>(Ty)) {
37850b57cec5SDimitry Andric         unsigned OldSize = Indices.size();
37860b57cec5SDimitry Andric         (void)OldSize;
37870b57cec5SDimitry Andric         for (unsigned Idx = 0, Size = STy->getNumElements(); Idx != Size;
37880b57cec5SDimitry Andric              ++Idx) {
37890b57cec5SDimitry Andric           assert(Indices.size() == OldSize && "Did not return to the old size");
37900b57cec5SDimitry Andric           Indices.push_back(Idx);
37910b57cec5SDimitry Andric           GEPIndices.push_back(IRB.getInt32(Idx));
37920b57cec5SDimitry Andric           emitSplitOps(STy->getElementType(Idx), Agg, Name + "." + Twine(Idx));
37930b57cec5SDimitry Andric           GEPIndices.pop_back();
37940b57cec5SDimitry Andric           Indices.pop_back();
37950b57cec5SDimitry Andric         }
37960b57cec5SDimitry Andric         return;
37970b57cec5SDimitry Andric       }
37980b57cec5SDimitry Andric 
37990b57cec5SDimitry Andric       llvm_unreachable("Only arrays and structs are aggregate loadable types");
38000b57cec5SDimitry Andric     }
38010b57cec5SDimitry Andric   };
38020b57cec5SDimitry Andric 
38030b57cec5SDimitry Andric   struct LoadOpSplitter : public OpSplitter<LoadOpSplitter> {
38040b57cec5SDimitry Andric     AAMDNodes AATags;
38050b57cec5SDimitry Andric 
38060b57cec5SDimitry Andric     LoadOpSplitter(Instruction *InsertionPoint, Value *Ptr, Type *BaseTy,
380704eeddc0SDimitry Andric                    AAMDNodes AATags, Align BaseAlign, const DataLayout &DL,
380804eeddc0SDimitry Andric                    IRBuilderTy &IRB)
380904eeddc0SDimitry Andric         : OpSplitter<LoadOpSplitter>(InsertionPoint, Ptr, BaseTy, BaseAlign, DL,
381004eeddc0SDimitry Andric                                      IRB),
3811480093f4SDimitry Andric           AATags(AATags) {}
38120b57cec5SDimitry Andric 
38130b57cec5SDimitry Andric     /// Emit a leaf load of a single value. This is called at the leaves of the
38140b57cec5SDimitry Andric     /// recursive emission to actually load values.
3815480093f4SDimitry Andric     void emitFunc(Type *Ty, Value *&Agg, Align Alignment, const Twine &Name) {
38160b57cec5SDimitry Andric       assert(Ty->isSingleValueType());
38170b57cec5SDimitry Andric       // Load the single value and insert it using the indices.
38180b57cec5SDimitry Andric       Value *GEP =
38190b57cec5SDimitry Andric           IRB.CreateInBoundsGEP(BaseTy, Ptr, GEPIndices, Name + ".gep");
3820480093f4SDimitry Andric       LoadInst *Load =
38215ffd83dbSDimitry Andric           IRB.CreateAlignedLoad(Ty, GEP, Alignment, Name + ".load");
3822d409305fSDimitry Andric 
3823d409305fSDimitry Andric       APInt Offset(
3824d409305fSDimitry Andric           DL.getIndexSizeInBits(Ptr->getType()->getPointerAddressSpace()), 0);
3825d409305fSDimitry Andric       if (AATags &&
3826d409305fSDimitry Andric           GEPOperator::accumulateConstantOffset(BaseTy, GEPIndices, DL, Offset))
3827*0fca6ea1SDimitry Andric         Load->setAAMetadata(
3828*0fca6ea1SDimitry Andric             AATags.adjustForAccess(Offset.getZExtValue(), Load->getType(), DL));
3829d409305fSDimitry Andric 
38300b57cec5SDimitry Andric       Agg = IRB.CreateInsertValue(Agg, Load, Indices, Name + ".insert");
38310b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          to: " << *Load << "\n");
38320b57cec5SDimitry Andric     }
38330b57cec5SDimitry Andric   };
38340b57cec5SDimitry Andric 
38350b57cec5SDimitry Andric   bool visitLoadInst(LoadInst &LI) {
38360b57cec5SDimitry Andric     assert(LI.getPointerOperand() == *U);
38370b57cec5SDimitry Andric     if (!LI.isSimple() || LI.getType()->isSingleValueType())
38380b57cec5SDimitry Andric       return false;
38390b57cec5SDimitry Andric 
38400b57cec5SDimitry Andric     // We have an aggregate being loaded, split it apart.
38410b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << LI << "\n");
3842349cc55cSDimitry Andric     LoadOpSplitter Splitter(&LI, *U, LI.getType(), LI.getAAMetadata(),
384304eeddc0SDimitry Andric                             getAdjustedAlignment(&LI, 0), DL, IRB);
384404eeddc0SDimitry Andric     Value *V = PoisonValue::get(LI.getType());
38450b57cec5SDimitry Andric     Splitter.emitSplitOps(LI.getType(), V, LI.getName() + ".fca");
38465ffd83dbSDimitry Andric     Visited.erase(&LI);
38470b57cec5SDimitry Andric     LI.replaceAllUsesWith(V);
38480b57cec5SDimitry Andric     LI.eraseFromParent();
38490b57cec5SDimitry Andric     return true;
38500b57cec5SDimitry Andric   }
38510b57cec5SDimitry Andric 
38520b57cec5SDimitry Andric   struct StoreOpSplitter : public OpSplitter<StoreOpSplitter> {
38530b57cec5SDimitry Andric     StoreOpSplitter(Instruction *InsertionPoint, Value *Ptr, Type *BaseTy,
3854bdd1243dSDimitry Andric                     AAMDNodes AATags, StoreInst *AggStore, Align BaseAlign,
3855bdd1243dSDimitry Andric                     const DataLayout &DL, IRBuilderTy &IRB)
38560b57cec5SDimitry Andric         : OpSplitter<StoreOpSplitter>(InsertionPoint, Ptr, BaseTy, BaseAlign,
385704eeddc0SDimitry Andric                                       DL, IRB),
3858bdd1243dSDimitry Andric           AATags(AATags), AggStore(AggStore) {}
38590b57cec5SDimitry Andric     AAMDNodes AATags;
3860bdd1243dSDimitry Andric     StoreInst *AggStore;
38610b57cec5SDimitry Andric     /// Emit a leaf store of a single value. This is called at the leaves of the
38620b57cec5SDimitry Andric     /// recursive emission to actually produce stores.
3863480093f4SDimitry Andric     void emitFunc(Type *Ty, Value *&Agg, Align Alignment, const Twine &Name) {
38640b57cec5SDimitry Andric       assert(Ty->isSingleValueType());
38650b57cec5SDimitry Andric       // Extract the single value and store it using the indices.
38660b57cec5SDimitry Andric       //
38670b57cec5SDimitry Andric       // The gep and extractvalue values are factored out of the CreateStore
38680b57cec5SDimitry Andric       // call to make the output independent of the argument evaluation order.
38690b57cec5SDimitry Andric       Value *ExtractValue =
38700b57cec5SDimitry Andric           IRB.CreateExtractValue(Agg, Indices, Name + ".extract");
38710b57cec5SDimitry Andric       Value *InBoundsGEP =
38720b57cec5SDimitry Andric           IRB.CreateInBoundsGEP(BaseTy, Ptr, GEPIndices, Name + ".gep");
38730b57cec5SDimitry Andric       StoreInst *Store =
38745ffd83dbSDimitry Andric           IRB.CreateAlignedStore(ExtractValue, InBoundsGEP, Alignment);
3875d409305fSDimitry Andric 
3876d409305fSDimitry Andric       APInt Offset(
3877d409305fSDimitry Andric           DL.getIndexSizeInBits(Ptr->getType()->getPointerAddressSpace()), 0);
387806c3fb27SDimitry Andric       GEPOperator::accumulateConstantOffset(BaseTy, GEPIndices, DL, Offset);
3879*0fca6ea1SDimitry Andric       if (AATags) {
3880*0fca6ea1SDimitry Andric         Store->setAAMetadata(AATags.adjustForAccess(
3881*0fca6ea1SDimitry Andric             Offset.getZExtValue(), ExtractValue->getType(), DL));
3882*0fca6ea1SDimitry Andric       }
3883d409305fSDimitry Andric 
3884bdd1243dSDimitry Andric       // migrateDebugInfo requires the base Alloca. Walk to it from this gep.
3885bdd1243dSDimitry Andric       // If we cannot (because there's an intervening non-const or unbounded
3886bdd1243dSDimitry Andric       // gep) then we wouldn't expect to see dbg.assign intrinsics linked to
3887bdd1243dSDimitry Andric       // this instruction.
388806c3fb27SDimitry Andric       Value *Base = AggStore->getPointerOperand()->stripInBoundsOffsets();
3889bdd1243dSDimitry Andric       if (auto *OldAI = dyn_cast<AllocaInst>(Base)) {
3890bdd1243dSDimitry Andric         uint64_t SizeInBits =
3891bdd1243dSDimitry Andric             DL.getTypeSizeInBits(Store->getValueOperand()->getType());
389206c3fb27SDimitry Andric         migrateDebugInfo(OldAI, /*IsSplit*/ true, Offset.getZExtValue() * 8,
389306c3fb27SDimitry Andric                          SizeInBits, AggStore, Store,
389406c3fb27SDimitry Andric                          Store->getPointerOperand(), Store->getValueOperand(),
389506c3fb27SDimitry Andric                          DL);
3896bdd1243dSDimitry Andric       } else {
3897bdd1243dSDimitry Andric         assert(at::getAssignmentMarkers(Store).empty() &&
3898*0fca6ea1SDimitry Andric                at::getDVRAssignmentMarkers(Store).empty() &&
3899bdd1243dSDimitry Andric                "AT: unexpected debug.assign linked to store through "
3900bdd1243dSDimitry Andric                "unbounded GEP");
3901bdd1243dSDimitry Andric       }
39020b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          to: " << *Store << "\n");
39030b57cec5SDimitry Andric     }
39040b57cec5SDimitry Andric   };
39050b57cec5SDimitry Andric 
39060b57cec5SDimitry Andric   bool visitStoreInst(StoreInst &SI) {
39070b57cec5SDimitry Andric     if (!SI.isSimple() || SI.getPointerOperand() != *U)
39080b57cec5SDimitry Andric       return false;
39090b57cec5SDimitry Andric     Value *V = SI.getValueOperand();
39100b57cec5SDimitry Andric     if (V->getType()->isSingleValueType())
39110b57cec5SDimitry Andric       return false;
39120b57cec5SDimitry Andric 
39130b57cec5SDimitry Andric     // We have an aggregate being stored, split it apart.
39140b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "    original: " << SI << "\n");
3915bdd1243dSDimitry Andric     StoreOpSplitter Splitter(&SI, *U, V->getType(), SI.getAAMetadata(), &SI,
391604eeddc0SDimitry Andric                              getAdjustedAlignment(&SI, 0), DL, IRB);
39170b57cec5SDimitry Andric     Splitter.emitSplitOps(V->getType(), V, V->getName() + ".fca");
39185ffd83dbSDimitry Andric     Visited.erase(&SI);
391906c3fb27SDimitry Andric     // The stores replacing SI each have markers describing fragments of the
392006c3fb27SDimitry Andric     // assignment so delete the assignment markers linked to SI.
392106c3fb27SDimitry Andric     at::deleteAssignmentMarkers(&SI);
39220b57cec5SDimitry Andric     SI.eraseFromParent();
39230b57cec5SDimitry Andric     return true;
39240b57cec5SDimitry Andric   }
39250b57cec5SDimitry Andric 
39260b57cec5SDimitry Andric   bool visitBitCastInst(BitCastInst &BC) {
39270b57cec5SDimitry Andric     enqueueUsers(BC);
39280b57cec5SDimitry Andric     return false;
39290b57cec5SDimitry Andric   }
39300b57cec5SDimitry Andric 
39310b57cec5SDimitry Andric   bool visitAddrSpaceCastInst(AddrSpaceCastInst &ASC) {
39320b57cec5SDimitry Andric     enqueueUsers(ASC);
39330b57cec5SDimitry Andric     return false;
39340b57cec5SDimitry Andric   }
39350b57cec5SDimitry Andric 
3936*0fca6ea1SDimitry Andric   // Unfold gep (select cond, ptr1, ptr2), idx
3937*0fca6ea1SDimitry Andric   //   => select cond, gep(ptr1, idx), gep(ptr2, idx)
3938*0fca6ea1SDimitry Andric   // and  gep ptr, (select cond, idx1, idx2)
3939*0fca6ea1SDimitry Andric   //   => select cond, gep(ptr, idx1), gep(ptr, idx2)
3940*0fca6ea1SDimitry Andric   bool unfoldGEPSelect(GetElementPtrInst &GEPI) {
3941*0fca6ea1SDimitry Andric     // Check whether the GEP has exactly one select operand and all indices
3942*0fca6ea1SDimitry Andric     // will become constant after the transform.
3943*0fca6ea1SDimitry Andric     SelectInst *Sel = dyn_cast<SelectInst>(GEPI.getPointerOperand());
3944*0fca6ea1SDimitry Andric     for (Value *Op : GEPI.indices()) {
3945*0fca6ea1SDimitry Andric       if (auto *SI = dyn_cast<SelectInst>(Op)) {
3946*0fca6ea1SDimitry Andric         if (Sel)
39475ffd83dbSDimitry Andric           return false;
39485ffd83dbSDimitry Andric 
3949*0fca6ea1SDimitry Andric         Sel = SI;
3950*0fca6ea1SDimitry Andric         if (!isa<ConstantInt>(Sel->getTrueValue()) ||
3951*0fca6ea1SDimitry Andric             !isa<ConstantInt>(Sel->getFalseValue()))
3952*0fca6ea1SDimitry Andric           return false;
3953*0fca6ea1SDimitry Andric         continue;
3954*0fca6ea1SDimitry Andric       }
39555ffd83dbSDimitry Andric 
3956*0fca6ea1SDimitry Andric       if (!isa<ConstantInt>(Op))
3957*0fca6ea1SDimitry Andric         return false;
3958*0fca6ea1SDimitry Andric     }
3959*0fca6ea1SDimitry Andric 
3960*0fca6ea1SDimitry Andric     if (!Sel)
3961*0fca6ea1SDimitry Andric       return false;
3962*0fca6ea1SDimitry Andric 
3963*0fca6ea1SDimitry Andric     LLVM_DEBUG(dbgs() << "  Rewriting gep(select) -> select(gep):\n";
3964*0fca6ea1SDimitry Andric                dbgs() << "    original: " << *Sel << "\n";
3965*0fca6ea1SDimitry Andric                dbgs() << "              " << GEPI << "\n";);
3966*0fca6ea1SDimitry Andric 
3967*0fca6ea1SDimitry Andric     auto GetNewOps = [&](Value *SelOp) {
3968*0fca6ea1SDimitry Andric       SmallVector<Value *> NewOps;
3969*0fca6ea1SDimitry Andric       for (Value *Op : GEPI.operands())
3970*0fca6ea1SDimitry Andric         if (Op == Sel)
3971*0fca6ea1SDimitry Andric           NewOps.push_back(SelOp);
3972*0fca6ea1SDimitry Andric         else
3973*0fca6ea1SDimitry Andric           NewOps.push_back(Op);
3974*0fca6ea1SDimitry Andric       return NewOps;
3975*0fca6ea1SDimitry Andric     };
3976*0fca6ea1SDimitry Andric 
3977*0fca6ea1SDimitry Andric     Value *True = Sel->getTrueValue();
3978*0fca6ea1SDimitry Andric     Value *False = Sel->getFalseValue();
3979*0fca6ea1SDimitry Andric     SmallVector<Value *> TrueOps = GetNewOps(True);
3980*0fca6ea1SDimitry Andric     SmallVector<Value *> FalseOps = GetNewOps(False);
39815ffd83dbSDimitry Andric 
398204eeddc0SDimitry Andric     IRB.SetInsertPoint(&GEPI);
3983*0fca6ea1SDimitry Andric     GEPNoWrapFlags NW = GEPI.getNoWrapFlags();
39845ffd83dbSDimitry Andric 
3985fe6060f1SDimitry Andric     Type *Ty = GEPI.getSourceElementType();
3986*0fca6ea1SDimitry Andric     Value *NTrue = IRB.CreateGEP(Ty, TrueOps[0], ArrayRef(TrueOps).drop_front(),
3987*0fca6ea1SDimitry Andric                                  True->getName() + ".sroa.gep", NW);
39885ffd83dbSDimitry Andric 
3989*0fca6ea1SDimitry Andric     Value *NFalse =
3990*0fca6ea1SDimitry Andric         IRB.CreateGEP(Ty, FalseOps[0], ArrayRef(FalseOps).drop_front(),
3991*0fca6ea1SDimitry Andric                       False->getName() + ".sroa.gep", NW);
39925ffd83dbSDimitry Andric 
399304eeddc0SDimitry Andric     Value *NSel = IRB.CreateSelect(Sel->getCondition(), NTrue, NFalse,
39945ffd83dbSDimitry Andric                                    Sel->getName() + ".sroa.sel");
39955ffd83dbSDimitry Andric     Visited.erase(&GEPI);
39965ffd83dbSDimitry Andric     GEPI.replaceAllUsesWith(NSel);
39975ffd83dbSDimitry Andric     GEPI.eraseFromParent();
39985ffd83dbSDimitry Andric     Instruction *NSelI = cast<Instruction>(NSel);
39995ffd83dbSDimitry Andric     Visited.insert(NSelI);
40005ffd83dbSDimitry Andric     enqueueUsers(*NSelI);
40015ffd83dbSDimitry Andric 
4002*0fca6ea1SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: " << *NTrue << "\n";
4003*0fca6ea1SDimitry Andric                dbgs() << "              " << *NFalse << "\n";
4004*0fca6ea1SDimitry Andric                dbgs() << "              " << *NSel << "\n";);
40055ffd83dbSDimitry Andric 
40065ffd83dbSDimitry Andric     return true;
40075ffd83dbSDimitry Andric   }
40085ffd83dbSDimitry Andric 
4009*0fca6ea1SDimitry Andric   // Unfold gep (phi ptr1, ptr2), idx
4010*0fca6ea1SDimitry Andric   //   => phi ((gep ptr1, idx), (gep ptr2, idx))
4011*0fca6ea1SDimitry Andric   // and  gep ptr, (phi idx1, idx2)
4012*0fca6ea1SDimitry Andric   //   => phi ((gep ptr, idx1), (gep ptr, idx2))
4013*0fca6ea1SDimitry Andric   bool unfoldGEPPhi(GetElementPtrInst &GEPI) {
4014*0fca6ea1SDimitry Andric     // To prevent infinitely expanding recursive phis, bail if the GEP pointer
4015*0fca6ea1SDimitry Andric     // operand (looking through the phi if it is the phi we want to unfold) is
4016*0fca6ea1SDimitry Andric     // an instruction besides a static alloca.
4017*0fca6ea1SDimitry Andric     PHINode *Phi = dyn_cast<PHINode>(GEPI.getPointerOperand());
4018*0fca6ea1SDimitry Andric     auto IsInvalidPointerOperand = [](Value *V) {
4019*0fca6ea1SDimitry Andric       if (!isa<Instruction>(V))
40205ffd83dbSDimitry Andric         return false;
4021*0fca6ea1SDimitry Andric       if (auto *AI = dyn_cast<AllocaInst>(V))
4022*0fca6ea1SDimitry Andric         return !AI->isStaticAlloca();
4023*0fca6ea1SDimitry Andric       return true;
4024*0fca6ea1SDimitry Andric     };
4025*0fca6ea1SDimitry Andric     if (Phi) {
4026*0fca6ea1SDimitry Andric       if (any_of(Phi->operands(), IsInvalidPointerOperand))
40275ffd83dbSDimitry Andric         return false;
4028e8d8bef9SDimitry Andric     } else {
4029*0fca6ea1SDimitry Andric       if (IsInvalidPointerOperand(GEPI.getPointerOperand()))
4030*0fca6ea1SDimitry Andric         return false;
4031e8d8bef9SDimitry Andric     }
4032*0fca6ea1SDimitry Andric     // Check whether the GEP has exactly one phi operand (including the pointer
4033*0fca6ea1SDimitry Andric     // operand) and all indices will become constant after the transform.
4034*0fca6ea1SDimitry Andric     for (Value *Op : GEPI.indices()) {
4035*0fca6ea1SDimitry Andric       if (auto *SI = dyn_cast<PHINode>(Op)) {
4036*0fca6ea1SDimitry Andric         if (Phi)
4037*0fca6ea1SDimitry Andric           return false;
4038*0fca6ea1SDimitry Andric 
4039*0fca6ea1SDimitry Andric         Phi = SI;
4040*0fca6ea1SDimitry Andric         if (!all_of(Phi->incoming_values(),
4041*0fca6ea1SDimitry Andric                     [](Value *V) { return isa<ConstantInt>(V); }))
4042*0fca6ea1SDimitry Andric           return false;
4043*0fca6ea1SDimitry Andric         continue;
4044*0fca6ea1SDimitry Andric       }
4045*0fca6ea1SDimitry Andric 
4046*0fca6ea1SDimitry Andric       if (!isa<ConstantInt>(Op))
4047*0fca6ea1SDimitry Andric         return false;
4048*0fca6ea1SDimitry Andric     }
4049*0fca6ea1SDimitry Andric 
4050*0fca6ea1SDimitry Andric     if (!Phi)
4051*0fca6ea1SDimitry Andric       return false;
4052*0fca6ea1SDimitry Andric 
4053*0fca6ea1SDimitry Andric     LLVM_DEBUG(dbgs() << "  Rewriting gep(phi) -> phi(gep):\n";
4054*0fca6ea1SDimitry Andric                dbgs() << "    original: " << *Phi << "\n";
4055*0fca6ea1SDimitry Andric                dbgs() << "              " << GEPI << "\n";);
4056*0fca6ea1SDimitry Andric 
4057*0fca6ea1SDimitry Andric     auto GetNewOps = [&](Value *PhiOp) {
4058*0fca6ea1SDimitry Andric       SmallVector<Value *> NewOps;
4059*0fca6ea1SDimitry Andric       for (Value *Op : GEPI.operands())
4060*0fca6ea1SDimitry Andric         if (Op == Phi)
4061*0fca6ea1SDimitry Andric           NewOps.push_back(PhiOp);
4062*0fca6ea1SDimitry Andric         else
4063*0fca6ea1SDimitry Andric           NewOps.push_back(Op);
4064*0fca6ea1SDimitry Andric       return NewOps;
4065*0fca6ea1SDimitry Andric     };
4066*0fca6ea1SDimitry Andric 
4067*0fca6ea1SDimitry Andric     IRB.SetInsertPoint(Phi);
4068*0fca6ea1SDimitry Andric     PHINode *NewPhi = IRB.CreatePHI(GEPI.getType(), Phi->getNumIncomingValues(),
4069*0fca6ea1SDimitry Andric                                     Phi->getName() + ".sroa.phi");
4070*0fca6ea1SDimitry Andric 
4071*0fca6ea1SDimitry Andric     Type *SourceTy = GEPI.getSourceElementType();
4072*0fca6ea1SDimitry Andric     // We only handle arguments, constants, and static allocas here, so we can
4073*0fca6ea1SDimitry Andric     // insert GEPs at the end of the entry block.
4074*0fca6ea1SDimitry Andric     IRB.SetInsertPoint(GEPI.getFunction()->getEntryBlock().getTerminator());
4075*0fca6ea1SDimitry Andric     for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
4076*0fca6ea1SDimitry Andric       Value *Op = Phi->getIncomingValue(I);
4077*0fca6ea1SDimitry Andric       BasicBlock *BB = Phi->getIncomingBlock(I);
4078*0fca6ea1SDimitry Andric       Value *NewGEP;
4079*0fca6ea1SDimitry Andric       if (int NI = NewPhi->getBasicBlockIndex(BB); NI >= 0) {
4080*0fca6ea1SDimitry Andric         NewGEP = NewPhi->getIncomingValue(NI);
4081*0fca6ea1SDimitry Andric       } else {
4082*0fca6ea1SDimitry Andric         SmallVector<Value *> NewOps = GetNewOps(Op);
4083*0fca6ea1SDimitry Andric         NewGEP =
4084*0fca6ea1SDimitry Andric             IRB.CreateGEP(SourceTy, NewOps[0], ArrayRef(NewOps).drop_front(),
4085*0fca6ea1SDimitry Andric                           Phi->getName() + ".sroa.gep", GEPI.getNoWrapFlags());
4086*0fca6ea1SDimitry Andric       }
4087*0fca6ea1SDimitry Andric       NewPhi->addIncoming(NewGEP, BB);
40885ffd83dbSDimitry Andric     }
40895ffd83dbSDimitry Andric 
40905ffd83dbSDimitry Andric     Visited.erase(&GEPI);
4091*0fca6ea1SDimitry Andric     GEPI.replaceAllUsesWith(NewPhi);
40925ffd83dbSDimitry Andric     GEPI.eraseFromParent();
4093*0fca6ea1SDimitry Andric     Visited.insert(NewPhi);
4094*0fca6ea1SDimitry Andric     enqueueUsers(*NewPhi);
40955ffd83dbSDimitry Andric 
4096*0fca6ea1SDimitry Andric     LLVM_DEBUG(dbgs() << "          to: ";
4097*0fca6ea1SDimitry Andric                for (Value *In
4098*0fca6ea1SDimitry Andric                     : NewPhi->incoming_values()) dbgs()
4099*0fca6ea1SDimitry Andric                << "\n              " << *In;
4100*0fca6ea1SDimitry Andric                dbgs() << "\n              " << *NewPhi << '\n');
41015ffd83dbSDimitry Andric 
41025ffd83dbSDimitry Andric     return true;
41035ffd83dbSDimitry Andric   }
41045ffd83dbSDimitry Andric 
41050b57cec5SDimitry Andric   bool visitGetElementPtrInst(GetElementPtrInst &GEPI) {
4106*0fca6ea1SDimitry Andric     if (unfoldGEPSelect(GEPI))
41075ffd83dbSDimitry Andric       return true;
41085ffd83dbSDimitry Andric 
4109*0fca6ea1SDimitry Andric     if (unfoldGEPPhi(GEPI))
41105ffd83dbSDimitry Andric       return true;
41115ffd83dbSDimitry Andric 
41120b57cec5SDimitry Andric     enqueueUsers(GEPI);
41130b57cec5SDimitry Andric     return false;
41140b57cec5SDimitry Andric   }
41150b57cec5SDimitry Andric 
41160b57cec5SDimitry Andric   bool visitPHINode(PHINode &PN) {
41170b57cec5SDimitry Andric     enqueueUsers(PN);
41180b57cec5SDimitry Andric     return false;
41190b57cec5SDimitry Andric   }
41200b57cec5SDimitry Andric 
41210b57cec5SDimitry Andric   bool visitSelectInst(SelectInst &SI) {
41220b57cec5SDimitry Andric     enqueueUsers(SI);
41230b57cec5SDimitry Andric     return false;
41240b57cec5SDimitry Andric   }
41250b57cec5SDimitry Andric };
41260b57cec5SDimitry Andric 
41270b57cec5SDimitry Andric } // end anonymous namespace
41280b57cec5SDimitry Andric 
41290b57cec5SDimitry Andric /// Strip aggregate type wrapping.
41300b57cec5SDimitry Andric ///
41310b57cec5SDimitry Andric /// This removes no-op aggregate types wrapping an underlying type. It will
41320b57cec5SDimitry Andric /// strip as many layers of types as it can without changing either the type
41330b57cec5SDimitry Andric /// size or the allocated size.
41340b57cec5SDimitry Andric static Type *stripAggregateTypeWrapping(const DataLayout &DL, Type *Ty) {
41350b57cec5SDimitry Andric   if (Ty->isSingleValueType())
41360b57cec5SDimitry Andric     return Ty;
41370b57cec5SDimitry Andric 
4138bdd1243dSDimitry Andric   uint64_t AllocSize = DL.getTypeAllocSize(Ty).getFixedValue();
4139bdd1243dSDimitry Andric   uint64_t TypeSize = DL.getTypeSizeInBits(Ty).getFixedValue();
41400b57cec5SDimitry Andric 
41410b57cec5SDimitry Andric   Type *InnerTy;
41420b57cec5SDimitry Andric   if (ArrayType *ArrTy = dyn_cast<ArrayType>(Ty)) {
41430b57cec5SDimitry Andric     InnerTy = ArrTy->getElementType();
41440b57cec5SDimitry Andric   } else if (StructType *STy = dyn_cast<StructType>(Ty)) {
41450b57cec5SDimitry Andric     const StructLayout *SL = DL.getStructLayout(STy);
41460b57cec5SDimitry Andric     unsigned Index = SL->getElementContainingOffset(0);
41470b57cec5SDimitry Andric     InnerTy = STy->getElementType(Index);
41480b57cec5SDimitry Andric   } else {
41490b57cec5SDimitry Andric     return Ty;
41500b57cec5SDimitry Andric   }
41510b57cec5SDimitry Andric 
4152bdd1243dSDimitry Andric   if (AllocSize > DL.getTypeAllocSize(InnerTy).getFixedValue() ||
4153bdd1243dSDimitry Andric       TypeSize > DL.getTypeSizeInBits(InnerTy).getFixedValue())
41540b57cec5SDimitry Andric     return Ty;
41550b57cec5SDimitry Andric 
41560b57cec5SDimitry Andric   return stripAggregateTypeWrapping(DL, InnerTy);
41570b57cec5SDimitry Andric }
41580b57cec5SDimitry Andric 
41590b57cec5SDimitry Andric /// Try to find a partition of the aggregate type passed in for a given
41600b57cec5SDimitry Andric /// offset and size.
41610b57cec5SDimitry Andric ///
41620b57cec5SDimitry Andric /// This recurses through the aggregate type and tries to compute a subtype
41630b57cec5SDimitry Andric /// based on the offset and size. When the offset and size span a sub-section
41640b57cec5SDimitry Andric /// of an array, it will even compute a new array type for that sub-section,
41650b57cec5SDimitry Andric /// and the same for structs.
41660b57cec5SDimitry Andric ///
41670b57cec5SDimitry Andric /// Note that this routine is very strict and tries to find a partition of the
41680b57cec5SDimitry Andric /// type which produces the *exact* right offset and size. It is not forgiving
41690b57cec5SDimitry Andric /// when the size or offset cause either end of type-based partition to be off.
41700b57cec5SDimitry Andric /// Also, this is a best-effort routine. It is reasonable to give up and not
41710b57cec5SDimitry Andric /// return a type if necessary.
41720b57cec5SDimitry Andric static Type *getTypePartition(const DataLayout &DL, Type *Ty, uint64_t Offset,
41730b57cec5SDimitry Andric                               uint64_t Size) {
4174bdd1243dSDimitry Andric   if (Offset == 0 && DL.getTypeAllocSize(Ty).getFixedValue() == Size)
41750b57cec5SDimitry Andric     return stripAggregateTypeWrapping(DL, Ty);
4176bdd1243dSDimitry Andric   if (Offset > DL.getTypeAllocSize(Ty).getFixedValue() ||
4177bdd1243dSDimitry Andric       (DL.getTypeAllocSize(Ty).getFixedValue() - Offset) < Size)
41780b57cec5SDimitry Andric     return nullptr;
41790b57cec5SDimitry Andric 
41805ffd83dbSDimitry Andric   if (isa<ArrayType>(Ty) || isa<VectorType>(Ty)) {
41815ffd83dbSDimitry Andric     Type *ElementTy;
41825ffd83dbSDimitry Andric     uint64_t TyNumElements;
41835ffd83dbSDimitry Andric     if (auto *AT = dyn_cast<ArrayType>(Ty)) {
41845ffd83dbSDimitry Andric       ElementTy = AT->getElementType();
41855ffd83dbSDimitry Andric       TyNumElements = AT->getNumElements();
41865ffd83dbSDimitry Andric     } else {
41875ffd83dbSDimitry Andric       // FIXME: This isn't right for vectors with non-byte-sized or
41885ffd83dbSDimitry Andric       // non-power-of-two sized elements.
41895ffd83dbSDimitry Andric       auto *VT = cast<FixedVectorType>(Ty);
41905ffd83dbSDimitry Andric       ElementTy = VT->getElementType();
41915ffd83dbSDimitry Andric       TyNumElements = VT->getNumElements();
41925ffd83dbSDimitry Andric     }
4193bdd1243dSDimitry Andric     uint64_t ElementSize = DL.getTypeAllocSize(ElementTy).getFixedValue();
41940b57cec5SDimitry Andric     uint64_t NumSkippedElements = Offset / ElementSize;
41955ffd83dbSDimitry Andric     if (NumSkippedElements >= TyNumElements)
41960b57cec5SDimitry Andric       return nullptr;
41970b57cec5SDimitry Andric     Offset -= NumSkippedElements * ElementSize;
41980b57cec5SDimitry Andric 
41990b57cec5SDimitry Andric     // First check if we need to recurse.
42000b57cec5SDimitry Andric     if (Offset > 0 || Size < ElementSize) {
42010b57cec5SDimitry Andric       // Bail if the partition ends in a different array element.
42020b57cec5SDimitry Andric       if ((Offset + Size) > ElementSize)
42030b57cec5SDimitry Andric         return nullptr;
42040b57cec5SDimitry Andric       // Recurse through the element type trying to peel off offset bytes.
42050b57cec5SDimitry Andric       return getTypePartition(DL, ElementTy, Offset, Size);
42060b57cec5SDimitry Andric     }
42070b57cec5SDimitry Andric     assert(Offset == 0);
42080b57cec5SDimitry Andric 
42090b57cec5SDimitry Andric     if (Size == ElementSize)
42100b57cec5SDimitry Andric       return stripAggregateTypeWrapping(DL, ElementTy);
42110b57cec5SDimitry Andric     assert(Size > ElementSize);
42120b57cec5SDimitry Andric     uint64_t NumElements = Size / ElementSize;
42130b57cec5SDimitry Andric     if (NumElements * ElementSize != Size)
42140b57cec5SDimitry Andric       return nullptr;
42150b57cec5SDimitry Andric     return ArrayType::get(ElementTy, NumElements);
42160b57cec5SDimitry Andric   }
42170b57cec5SDimitry Andric 
42180b57cec5SDimitry Andric   StructType *STy = dyn_cast<StructType>(Ty);
42190b57cec5SDimitry Andric   if (!STy)
42200b57cec5SDimitry Andric     return nullptr;
42210b57cec5SDimitry Andric 
42220b57cec5SDimitry Andric   const StructLayout *SL = DL.getStructLayout(STy);
422306c3fb27SDimitry Andric 
422406c3fb27SDimitry Andric   if (SL->getSizeInBits().isScalable())
422506c3fb27SDimitry Andric     return nullptr;
422606c3fb27SDimitry Andric 
42270b57cec5SDimitry Andric   if (Offset >= SL->getSizeInBytes())
42280b57cec5SDimitry Andric     return nullptr;
42290b57cec5SDimitry Andric   uint64_t EndOffset = Offset + Size;
42300b57cec5SDimitry Andric   if (EndOffset > SL->getSizeInBytes())
42310b57cec5SDimitry Andric     return nullptr;
42320b57cec5SDimitry Andric 
42330b57cec5SDimitry Andric   unsigned Index = SL->getElementContainingOffset(Offset);
42340b57cec5SDimitry Andric   Offset -= SL->getElementOffset(Index);
42350b57cec5SDimitry Andric 
42360b57cec5SDimitry Andric   Type *ElementTy = STy->getElementType(Index);
4237bdd1243dSDimitry Andric   uint64_t ElementSize = DL.getTypeAllocSize(ElementTy).getFixedValue();
42380b57cec5SDimitry Andric   if (Offset >= ElementSize)
42390b57cec5SDimitry Andric     return nullptr; // The offset points into alignment padding.
42400b57cec5SDimitry Andric 
42410b57cec5SDimitry Andric   // See if any partition must be contained by the element.
42420b57cec5SDimitry Andric   if (Offset > 0 || Size < ElementSize) {
42430b57cec5SDimitry Andric     if ((Offset + Size) > ElementSize)
42440b57cec5SDimitry Andric       return nullptr;
42450b57cec5SDimitry Andric     return getTypePartition(DL, ElementTy, Offset, Size);
42460b57cec5SDimitry Andric   }
42470b57cec5SDimitry Andric   assert(Offset == 0);
42480b57cec5SDimitry Andric 
42490b57cec5SDimitry Andric   if (Size == ElementSize)
42500b57cec5SDimitry Andric     return stripAggregateTypeWrapping(DL, ElementTy);
42510b57cec5SDimitry Andric 
42520b57cec5SDimitry Andric   StructType::element_iterator EI = STy->element_begin() + Index,
42530b57cec5SDimitry Andric                                EE = STy->element_end();
42540b57cec5SDimitry Andric   if (EndOffset < SL->getSizeInBytes()) {
42550b57cec5SDimitry Andric     unsigned EndIndex = SL->getElementContainingOffset(EndOffset);
42560b57cec5SDimitry Andric     if (Index == EndIndex)
42570b57cec5SDimitry Andric       return nullptr; // Within a single element and its padding.
42580b57cec5SDimitry Andric 
42590b57cec5SDimitry Andric     // Don't try to form "natural" types if the elements don't line up with the
42600b57cec5SDimitry Andric     // expected size.
42610b57cec5SDimitry Andric     // FIXME: We could potentially recurse down through the last element in the
42620b57cec5SDimitry Andric     // sub-struct to find a natural end point.
42630b57cec5SDimitry Andric     if (SL->getElementOffset(EndIndex) != EndOffset)
42640b57cec5SDimitry Andric       return nullptr;
42650b57cec5SDimitry Andric 
42660b57cec5SDimitry Andric     assert(Index < EndIndex);
42670b57cec5SDimitry Andric     EE = STy->element_begin() + EndIndex;
42680b57cec5SDimitry Andric   }
42690b57cec5SDimitry Andric 
42700b57cec5SDimitry Andric   // Try to build up a sub-structure.
42710b57cec5SDimitry Andric   StructType *SubTy =
4272bdd1243dSDimitry Andric       StructType::get(STy->getContext(), ArrayRef(EI, EE), STy->isPacked());
42730b57cec5SDimitry Andric   const StructLayout *SubSL = DL.getStructLayout(SubTy);
42740b57cec5SDimitry Andric   if (Size != SubSL->getSizeInBytes())
42750b57cec5SDimitry Andric     return nullptr; // The sub-struct doesn't have quite the size needed.
42760b57cec5SDimitry Andric 
42770b57cec5SDimitry Andric   return SubTy;
42780b57cec5SDimitry Andric }
42790b57cec5SDimitry Andric 
42800b57cec5SDimitry Andric /// Pre-split loads and stores to simplify rewriting.
42810b57cec5SDimitry Andric ///
42820b57cec5SDimitry Andric /// We want to break up the splittable load+store pairs as much as
42830b57cec5SDimitry Andric /// possible. This is important to do as a preprocessing step, as once we
42840b57cec5SDimitry Andric /// start rewriting the accesses to partitions of the alloca we lose the
42850b57cec5SDimitry Andric /// necessary information to correctly split apart paired loads and stores
42860b57cec5SDimitry Andric /// which both point into this alloca. The case to consider is something like
42870b57cec5SDimitry Andric /// the following:
42880b57cec5SDimitry Andric ///
42890b57cec5SDimitry Andric ///   %a = alloca [12 x i8]
4290bdd1243dSDimitry Andric ///   %gep1 = getelementptr i8, ptr %a, i32 0
4291bdd1243dSDimitry Andric ///   %gep2 = getelementptr i8, ptr %a, i32 4
4292bdd1243dSDimitry Andric ///   %gep3 = getelementptr i8, ptr %a, i32 8
4293bdd1243dSDimitry Andric ///   store float 0.0, ptr %gep1
4294bdd1243dSDimitry Andric ///   store float 1.0, ptr %gep2
4295bdd1243dSDimitry Andric ///   %v = load i64, ptr %gep1
4296bdd1243dSDimitry Andric ///   store i64 %v, ptr %gep2
4297bdd1243dSDimitry Andric ///   %f1 = load float, ptr %gep2
4298bdd1243dSDimitry Andric ///   %f2 = load float, ptr %gep3
42990b57cec5SDimitry Andric ///
43000b57cec5SDimitry Andric /// Here we want to form 3 partitions of the alloca, each 4 bytes large, and
43010b57cec5SDimitry Andric /// promote everything so we recover the 2 SSA values that should have been
43020b57cec5SDimitry Andric /// there all along.
43030b57cec5SDimitry Andric ///
43040b57cec5SDimitry Andric /// \returns true if any changes are made.
43055f757f3fSDimitry Andric bool SROA::presplitLoadsAndStores(AllocaInst &AI, AllocaSlices &AS) {
43060b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "Pre-splitting loads and stores\n");
43070b57cec5SDimitry Andric 
43080b57cec5SDimitry Andric   // Track the loads and stores which are candidates for pre-splitting here, in
43090b57cec5SDimitry Andric   // the order they first appear during the partition scan. These give stable
43100b57cec5SDimitry Andric   // iteration order and a basis for tracking which loads and stores we
43110b57cec5SDimitry Andric   // actually split.
43120b57cec5SDimitry Andric   SmallVector<LoadInst *, 4> Loads;
43130b57cec5SDimitry Andric   SmallVector<StoreInst *, 4> Stores;
43140b57cec5SDimitry Andric 
43150b57cec5SDimitry Andric   // We need to accumulate the splits required of each load or store where we
43160b57cec5SDimitry Andric   // can find them via a direct lookup. This is important to cross-check loads
43170b57cec5SDimitry Andric   // and stores against each other. We also track the slice so that we can kill
43180b57cec5SDimitry Andric   // all the slices that end up split.
43190b57cec5SDimitry Andric   struct SplitOffsets {
43200b57cec5SDimitry Andric     Slice *S;
43210b57cec5SDimitry Andric     std::vector<uint64_t> Splits;
43220b57cec5SDimitry Andric   };
43230b57cec5SDimitry Andric   SmallDenseMap<Instruction *, SplitOffsets, 8> SplitOffsetsMap;
43240b57cec5SDimitry Andric 
43250b57cec5SDimitry Andric   // Track loads out of this alloca which cannot, for any reason, be pre-split.
43260b57cec5SDimitry Andric   // This is important as we also cannot pre-split stores of those loads!
43270b57cec5SDimitry Andric   // FIXME: This is all pretty gross. It means that we can be more aggressive
43280b57cec5SDimitry Andric   // in pre-splitting when the load feeding the store happens to come from
43290b57cec5SDimitry Andric   // a separate alloca. Put another way, the effectiveness of SROA would be
43300b57cec5SDimitry Andric   // decreased by a frontend which just concatenated all of its local allocas
43310b57cec5SDimitry Andric   // into one big flat alloca. But defeating such patterns is exactly the job
43320b57cec5SDimitry Andric   // SROA is tasked with! Sadly, to not have this discrepancy we would have
43330b57cec5SDimitry Andric   // change store pre-splitting to actually force pre-splitting of the load
43340b57cec5SDimitry Andric   // that feeds it *and all stores*. That makes pre-splitting much harder, but
43350b57cec5SDimitry Andric   // maybe it would make it more principled?
43360b57cec5SDimitry Andric   SmallPtrSet<LoadInst *, 8> UnsplittableLoads;
43370b57cec5SDimitry Andric 
43380b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "  Searching for candidate loads and stores\n");
43390b57cec5SDimitry Andric   for (auto &P : AS.partitions()) {
43400b57cec5SDimitry Andric     for (Slice &S : P) {
43410b57cec5SDimitry Andric       Instruction *I = cast<Instruction>(S.getUse()->getUser());
43420b57cec5SDimitry Andric       if (!S.isSplittable() || S.endOffset() <= P.endOffset()) {
43430b57cec5SDimitry Andric         // If this is a load we have to track that it can't participate in any
43440b57cec5SDimitry Andric         // pre-splitting. If this is a store of a load we have to track that
43450b57cec5SDimitry Andric         // that load also can't participate in any pre-splitting.
43460b57cec5SDimitry Andric         if (auto *LI = dyn_cast<LoadInst>(I))
43470b57cec5SDimitry Andric           UnsplittableLoads.insert(LI);
43480b57cec5SDimitry Andric         else if (auto *SI = dyn_cast<StoreInst>(I))
43490b57cec5SDimitry Andric           if (auto *LI = dyn_cast<LoadInst>(SI->getValueOperand()))
43500b57cec5SDimitry Andric             UnsplittableLoads.insert(LI);
43510b57cec5SDimitry Andric         continue;
43520b57cec5SDimitry Andric       }
43530b57cec5SDimitry Andric       assert(P.endOffset() > S.beginOffset() &&
43540b57cec5SDimitry Andric              "Empty or backwards partition!");
43550b57cec5SDimitry Andric 
43560b57cec5SDimitry Andric       // Determine if this is a pre-splittable slice.
43570b57cec5SDimitry Andric       if (auto *LI = dyn_cast<LoadInst>(I)) {
43580b57cec5SDimitry Andric         assert(!LI->isVolatile() && "Cannot split volatile loads!");
43590b57cec5SDimitry Andric 
43600b57cec5SDimitry Andric         // The load must be used exclusively to store into other pointers for
43610b57cec5SDimitry Andric         // us to be able to arbitrarily pre-split it. The stores must also be
43620b57cec5SDimitry Andric         // simple to avoid changing semantics.
43630b57cec5SDimitry Andric         auto IsLoadSimplyStored = [](LoadInst *LI) {
43640b57cec5SDimitry Andric           for (User *LU : LI->users()) {
43650b57cec5SDimitry Andric             auto *SI = dyn_cast<StoreInst>(LU);
43660b57cec5SDimitry Andric             if (!SI || !SI->isSimple())
43670b57cec5SDimitry Andric               return false;
43680b57cec5SDimitry Andric           }
43690b57cec5SDimitry Andric           return true;
43700b57cec5SDimitry Andric         };
43710b57cec5SDimitry Andric         if (!IsLoadSimplyStored(LI)) {
43720b57cec5SDimitry Andric           UnsplittableLoads.insert(LI);
43730b57cec5SDimitry Andric           continue;
43740b57cec5SDimitry Andric         }
43750b57cec5SDimitry Andric 
43760b57cec5SDimitry Andric         Loads.push_back(LI);
43770b57cec5SDimitry Andric       } else if (auto *SI = dyn_cast<StoreInst>(I)) {
43780b57cec5SDimitry Andric         if (S.getUse() != &SI->getOperandUse(SI->getPointerOperandIndex()))
43790b57cec5SDimitry Andric           // Skip stores *of* pointers. FIXME: This shouldn't even be possible!
43800b57cec5SDimitry Andric           continue;
43810b57cec5SDimitry Andric         auto *StoredLoad = dyn_cast<LoadInst>(SI->getValueOperand());
43820b57cec5SDimitry Andric         if (!StoredLoad || !StoredLoad->isSimple())
43830b57cec5SDimitry Andric           continue;
43840b57cec5SDimitry Andric         assert(!SI->isVolatile() && "Cannot split volatile stores!");
43850b57cec5SDimitry Andric 
43860b57cec5SDimitry Andric         Stores.push_back(SI);
43870b57cec5SDimitry Andric       } else {
43880b57cec5SDimitry Andric         // Other uses cannot be pre-split.
43890b57cec5SDimitry Andric         continue;
43900b57cec5SDimitry Andric       }
43910b57cec5SDimitry Andric 
43920b57cec5SDimitry Andric       // Record the initial split.
43930b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "    Candidate: " << *I << "\n");
43940b57cec5SDimitry Andric       auto &Offsets = SplitOffsetsMap[I];
43950b57cec5SDimitry Andric       assert(Offsets.Splits.empty() &&
43960b57cec5SDimitry Andric              "Should not have splits the first time we see an instruction!");
43970b57cec5SDimitry Andric       Offsets.S = &S;
43980b57cec5SDimitry Andric       Offsets.Splits.push_back(P.endOffset() - S.beginOffset());
43990b57cec5SDimitry Andric     }
44000b57cec5SDimitry Andric 
44010b57cec5SDimitry Andric     // Now scan the already split slices, and add a split for any of them which
44020b57cec5SDimitry Andric     // we're going to pre-split.
44030b57cec5SDimitry Andric     for (Slice *S : P.splitSliceTails()) {
44040b57cec5SDimitry Andric       auto SplitOffsetsMapI =
44050b57cec5SDimitry Andric           SplitOffsetsMap.find(cast<Instruction>(S->getUse()->getUser()));
44060b57cec5SDimitry Andric       if (SplitOffsetsMapI == SplitOffsetsMap.end())
44070b57cec5SDimitry Andric         continue;
44080b57cec5SDimitry Andric       auto &Offsets = SplitOffsetsMapI->second;
44090b57cec5SDimitry Andric 
44100b57cec5SDimitry Andric       assert(Offsets.S == S && "Found a mismatched slice!");
44110b57cec5SDimitry Andric       assert(!Offsets.Splits.empty() &&
44120b57cec5SDimitry Andric              "Cannot have an empty set of splits on the second partition!");
44130b57cec5SDimitry Andric       assert(Offsets.Splits.back() ==
44140b57cec5SDimitry Andric                  P.beginOffset() - Offsets.S->beginOffset() &&
44150b57cec5SDimitry Andric              "Previous split does not end where this one begins!");
44160b57cec5SDimitry Andric 
44170b57cec5SDimitry Andric       // Record each split. The last partition's end isn't needed as the size
44180b57cec5SDimitry Andric       // of the slice dictates that.
44190b57cec5SDimitry Andric       if (S->endOffset() > P.endOffset())
44200b57cec5SDimitry Andric         Offsets.Splits.push_back(P.endOffset() - Offsets.S->beginOffset());
44210b57cec5SDimitry Andric     }
44220b57cec5SDimitry Andric   }
44230b57cec5SDimitry Andric 
44240b57cec5SDimitry Andric   // We may have split loads where some of their stores are split stores. For
44250b57cec5SDimitry Andric   // such loads and stores, we can only pre-split them if their splits exactly
44260b57cec5SDimitry Andric   // match relative to their starting offset. We have to verify this prior to
44270b57cec5SDimitry Andric   // any rewriting.
4428e8d8bef9SDimitry Andric   llvm::erase_if(Stores, [&UnsplittableLoads, &SplitOffsetsMap](StoreInst *SI) {
44290b57cec5SDimitry Andric     // Lookup the load we are storing in our map of split
44300b57cec5SDimitry Andric     // offsets.
44310b57cec5SDimitry Andric     auto *LI = cast<LoadInst>(SI->getValueOperand());
44320b57cec5SDimitry Andric     // If it was completely unsplittable, then we're done,
44330b57cec5SDimitry Andric     // and this store can't be pre-split.
44340b57cec5SDimitry Andric     if (UnsplittableLoads.count(LI))
44350b57cec5SDimitry Andric       return true;
44360b57cec5SDimitry Andric 
44370b57cec5SDimitry Andric     auto LoadOffsetsI = SplitOffsetsMap.find(LI);
44380b57cec5SDimitry Andric     if (LoadOffsetsI == SplitOffsetsMap.end())
44390b57cec5SDimitry Andric       return false; // Unrelated loads are definitely safe.
44400b57cec5SDimitry Andric     auto &LoadOffsets = LoadOffsetsI->second;
44410b57cec5SDimitry Andric 
44420b57cec5SDimitry Andric     // Now lookup the store's offsets.
44430b57cec5SDimitry Andric     auto &StoreOffsets = SplitOffsetsMap[SI];
44440b57cec5SDimitry Andric 
44450b57cec5SDimitry Andric     // If the relative offsets of each split in the load and
44460b57cec5SDimitry Andric     // store match exactly, then we can split them and we
44470b57cec5SDimitry Andric     // don't need to remove them here.
44480b57cec5SDimitry Andric     if (LoadOffsets.Splits == StoreOffsets.Splits)
44490b57cec5SDimitry Andric       return false;
44500b57cec5SDimitry Andric 
4451e8d8bef9SDimitry Andric     LLVM_DEBUG(dbgs() << "    Mismatched splits for load and store:\n"
44520b57cec5SDimitry Andric                       << "      " << *LI << "\n"
44530b57cec5SDimitry Andric                       << "      " << *SI << "\n");
44540b57cec5SDimitry Andric 
44550b57cec5SDimitry Andric     // We've found a store and load that we need to split
44560b57cec5SDimitry Andric     // with mismatched relative splits. Just give up on them
44570b57cec5SDimitry Andric     // and remove both instructions from our list of
44580b57cec5SDimitry Andric     // candidates.
44590b57cec5SDimitry Andric     UnsplittableLoads.insert(LI);
44600b57cec5SDimitry Andric     return true;
4461e8d8bef9SDimitry Andric   });
44620b57cec5SDimitry Andric   // Now we have to go *back* through all the stores, because a later store may
44630b57cec5SDimitry Andric   // have caused an earlier store's load to become unsplittable and if it is
44640b57cec5SDimitry Andric   // unsplittable for the later store, then we can't rely on it being split in
44650b57cec5SDimitry Andric   // the earlier store either.
4466e8d8bef9SDimitry Andric   llvm::erase_if(Stores, [&UnsplittableLoads](StoreInst *SI) {
4467e8d8bef9SDimitry Andric     auto *LI = cast<LoadInst>(SI->getValueOperand());
44680b57cec5SDimitry Andric     return UnsplittableLoads.count(LI);
4469e8d8bef9SDimitry Andric   });
44700b57cec5SDimitry Andric   // Once we've established all the loads that can't be split for some reason,
44710b57cec5SDimitry Andric   // filter any that made it into our list out.
4472e8d8bef9SDimitry Andric   llvm::erase_if(Loads, [&UnsplittableLoads](LoadInst *LI) {
44730b57cec5SDimitry Andric     return UnsplittableLoads.count(LI);
4474e8d8bef9SDimitry Andric   });
44750b57cec5SDimitry Andric 
44760b57cec5SDimitry Andric   // If no loads or stores are left, there is no pre-splitting to be done for
44770b57cec5SDimitry Andric   // this alloca.
44780b57cec5SDimitry Andric   if (Loads.empty() && Stores.empty())
44790b57cec5SDimitry Andric     return false;
44800b57cec5SDimitry Andric 
44810b57cec5SDimitry Andric   // From here on, we can't fail and will be building new accesses, so rig up
44820b57cec5SDimitry Andric   // an IR builder.
44830b57cec5SDimitry Andric   IRBuilderTy IRB(&AI);
44840b57cec5SDimitry Andric 
44850b57cec5SDimitry Andric   // Collect the new slices which we will merge into the alloca slices.
44860b57cec5SDimitry Andric   SmallVector<Slice, 4> NewSlices;
44870b57cec5SDimitry Andric 
44880b57cec5SDimitry Andric   // Track any allocas we end up splitting loads and stores for so we iterate
44890b57cec5SDimitry Andric   // on them.
44900b57cec5SDimitry Andric   SmallPtrSet<AllocaInst *, 4> ResplitPromotableAllocas;
44910b57cec5SDimitry Andric 
44920b57cec5SDimitry Andric   // At this point, we have collected all of the loads and stores we can
44930b57cec5SDimitry Andric   // pre-split, and the specific splits needed for them. We actually do the
44940b57cec5SDimitry Andric   // splitting in a specific order in order to handle when one of the loads in
44950b57cec5SDimitry Andric   // the value operand to one of the stores.
44960b57cec5SDimitry Andric   //
44970b57cec5SDimitry Andric   // First, we rewrite all of the split loads, and just accumulate each split
44980b57cec5SDimitry Andric   // load in a parallel structure. We also build the slices for them and append
44990b57cec5SDimitry Andric   // them to the alloca slices.
45000b57cec5SDimitry Andric   SmallDenseMap<LoadInst *, std::vector<LoadInst *>, 1> SplitLoadsMap;
45010b57cec5SDimitry Andric   std::vector<LoadInst *> SplitLoads;
4502*0fca6ea1SDimitry Andric   const DataLayout &DL = AI.getDataLayout();
45030b57cec5SDimitry Andric   for (LoadInst *LI : Loads) {
45040b57cec5SDimitry Andric     SplitLoads.clear();
45050b57cec5SDimitry Andric 
45060b57cec5SDimitry Andric     auto &Offsets = SplitOffsetsMap[LI];
450781ad6265SDimitry Andric     unsigned SliceSize = Offsets.S->endOffset() - Offsets.S->beginOffset();
450881ad6265SDimitry Andric     assert(LI->getType()->getIntegerBitWidth() % 8 == 0 &&
450981ad6265SDimitry Andric            "Load must have type size equal to store size");
451081ad6265SDimitry Andric     assert(LI->getType()->getIntegerBitWidth() / 8 >= SliceSize &&
451181ad6265SDimitry Andric            "Load must be >= slice size");
451281ad6265SDimitry Andric 
45130b57cec5SDimitry Andric     uint64_t BaseOffset = Offsets.S->beginOffset();
451481ad6265SDimitry Andric     assert(BaseOffset + SliceSize > BaseOffset &&
45150b57cec5SDimitry Andric            "Cannot represent alloca access size using 64-bit integers!");
45160b57cec5SDimitry Andric 
45170b57cec5SDimitry Andric     Instruction *BasePtr = cast<Instruction>(LI->getPointerOperand());
45180b57cec5SDimitry Andric     IRB.SetInsertPoint(LI);
45190b57cec5SDimitry Andric 
45200b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "  Splitting load: " << *LI << "\n");
45210b57cec5SDimitry Andric 
45220b57cec5SDimitry Andric     uint64_t PartOffset = 0, PartSize = Offsets.Splits.front();
45230b57cec5SDimitry Andric     int Idx = 0, Size = Offsets.Splits.size();
45240b57cec5SDimitry Andric     for (;;) {
452581ad6265SDimitry Andric       auto *PartTy = Type::getIntNTy(LI->getContext(), PartSize * 8);
45260b57cec5SDimitry Andric       auto AS = LI->getPointerAddressSpace();
45275f757f3fSDimitry Andric       auto *PartPtrTy = LI->getPointerOperandType();
45280b57cec5SDimitry Andric       LoadInst *PLoad = IRB.CreateAlignedLoad(
45290b57cec5SDimitry Andric           PartTy,
45300b57cec5SDimitry Andric           getAdjustedPtr(IRB, DL, BasePtr,
45310b57cec5SDimitry Andric                          APInt(DL.getIndexSizeInBits(AS), PartOffset),
45320b57cec5SDimitry Andric                          PartPtrTy, BasePtr->getName() + "."),
45335ffd83dbSDimitry Andric           getAdjustedAlignment(LI, PartOffset),
4534480093f4SDimitry Andric           /*IsVolatile*/ false, LI->getName());
45350b57cec5SDimitry Andric       PLoad->copyMetadata(*LI, {LLVMContext::MD_mem_parallel_loop_access,
45360b57cec5SDimitry Andric                                 LLVMContext::MD_access_group});
45370b57cec5SDimitry Andric 
45380b57cec5SDimitry Andric       // Append this load onto the list of split loads so we can find it later
45390b57cec5SDimitry Andric       // to rewrite the stores.
45400b57cec5SDimitry Andric       SplitLoads.push_back(PLoad);
45410b57cec5SDimitry Andric 
45420b57cec5SDimitry Andric       // Now build a new slice for the alloca.
45430b57cec5SDimitry Andric       NewSlices.push_back(
45440b57cec5SDimitry Andric           Slice(BaseOffset + PartOffset, BaseOffset + PartOffset + PartSize,
45450b57cec5SDimitry Andric                 &PLoad->getOperandUse(PLoad->getPointerOperandIndex()),
45460b57cec5SDimitry Andric                 /*IsSplittable*/ false));
45470b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "    new slice [" << NewSlices.back().beginOffset()
45480b57cec5SDimitry Andric                         << ", " << NewSlices.back().endOffset()
45490b57cec5SDimitry Andric                         << "): " << *PLoad << "\n");
45500b57cec5SDimitry Andric 
45510b57cec5SDimitry Andric       // See if we've handled all the splits.
45520b57cec5SDimitry Andric       if (Idx >= Size)
45530b57cec5SDimitry Andric         break;
45540b57cec5SDimitry Andric 
45550b57cec5SDimitry Andric       // Setup the next partition.
45560b57cec5SDimitry Andric       PartOffset = Offsets.Splits[Idx];
45570b57cec5SDimitry Andric       ++Idx;
455881ad6265SDimitry Andric       PartSize = (Idx < Size ? Offsets.Splits[Idx] : SliceSize) - PartOffset;
45590b57cec5SDimitry Andric     }
45600b57cec5SDimitry Andric 
45610b57cec5SDimitry Andric     // Now that we have the split loads, do the slow walk over all uses of the
45620b57cec5SDimitry Andric     // load and rewrite them as split stores, or save the split loads to use
45630b57cec5SDimitry Andric     // below if the store is going to be split there anyways.
45640b57cec5SDimitry Andric     bool DeferredStores = false;
45650b57cec5SDimitry Andric     for (User *LU : LI->users()) {
45660b57cec5SDimitry Andric       StoreInst *SI = cast<StoreInst>(LU);
45670b57cec5SDimitry Andric       if (!Stores.empty() && SplitOffsetsMap.count(SI)) {
45680b57cec5SDimitry Andric         DeferredStores = true;
45690b57cec5SDimitry Andric         LLVM_DEBUG(dbgs() << "    Deferred splitting of store: " << *SI
45700b57cec5SDimitry Andric                           << "\n");
45710b57cec5SDimitry Andric         continue;
45720b57cec5SDimitry Andric       }
45730b57cec5SDimitry Andric 
45740b57cec5SDimitry Andric       Value *StoreBasePtr = SI->getPointerOperand();
45750b57cec5SDimitry Andric       IRB.SetInsertPoint(SI);
4576*0fca6ea1SDimitry Andric       AAMDNodes AATags = SI->getAAMetadata();
45770b57cec5SDimitry Andric 
45780b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "    Splitting store of load: " << *SI << "\n");
45790b57cec5SDimitry Andric 
45800b57cec5SDimitry Andric       for (int Idx = 0, Size = SplitLoads.size(); Idx < Size; ++Idx) {
45810b57cec5SDimitry Andric         LoadInst *PLoad = SplitLoads[Idx];
45820b57cec5SDimitry Andric         uint64_t PartOffset = Idx == 0 ? 0 : Offsets.Splits[Idx - 1];
45835f757f3fSDimitry Andric         auto *PartPtrTy = SI->getPointerOperandType();
45840b57cec5SDimitry Andric 
45850b57cec5SDimitry Andric         auto AS = SI->getPointerAddressSpace();
45860b57cec5SDimitry Andric         StoreInst *PStore = IRB.CreateAlignedStore(
45870b57cec5SDimitry Andric             PLoad,
45880b57cec5SDimitry Andric             getAdjustedPtr(IRB, DL, StoreBasePtr,
45890b57cec5SDimitry Andric                            APInt(DL.getIndexSizeInBits(AS), PartOffset),
45900b57cec5SDimitry Andric                            PartPtrTy, StoreBasePtr->getName() + "."),
45915ffd83dbSDimitry Andric             getAdjustedAlignment(SI, PartOffset),
4592480093f4SDimitry Andric             /*IsVolatile*/ false);
4593fe6060f1SDimitry Andric         PStore->copyMetadata(*SI, {LLVMContext::MD_mem_parallel_loop_access,
4594bdd1243dSDimitry Andric                                    LLVMContext::MD_access_group,
4595bdd1243dSDimitry Andric                                    LLVMContext::MD_DIAssignID});
4596*0fca6ea1SDimitry Andric 
4597*0fca6ea1SDimitry Andric         if (AATags)
4598*0fca6ea1SDimitry Andric           PStore->setAAMetadata(
4599*0fca6ea1SDimitry Andric               AATags.adjustForAccess(PartOffset, PLoad->getType(), DL));
46000b57cec5SDimitry Andric         LLVM_DEBUG(dbgs() << "      +" << PartOffset << ":" << *PStore << "\n");
46010b57cec5SDimitry Andric       }
46020b57cec5SDimitry Andric 
46030b57cec5SDimitry Andric       // We want to immediately iterate on any allocas impacted by splitting
46040b57cec5SDimitry Andric       // this store, and we have to track any promotable alloca (indicated by
46050b57cec5SDimitry Andric       // a direct store) as needing to be resplit because it is no longer
46060b57cec5SDimitry Andric       // promotable.
46070b57cec5SDimitry Andric       if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(StoreBasePtr)) {
46080b57cec5SDimitry Andric         ResplitPromotableAllocas.insert(OtherAI);
46090b57cec5SDimitry Andric         Worklist.insert(OtherAI);
46100b57cec5SDimitry Andric       } else if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(
46110b57cec5SDimitry Andric                      StoreBasePtr->stripInBoundsOffsets())) {
46120b57cec5SDimitry Andric         Worklist.insert(OtherAI);
46130b57cec5SDimitry Andric       }
46140b57cec5SDimitry Andric 
46150b57cec5SDimitry Andric       // Mark the original store as dead.
4616e8d8bef9SDimitry Andric       DeadInsts.push_back(SI);
46170b57cec5SDimitry Andric     }
46180b57cec5SDimitry Andric 
46190b57cec5SDimitry Andric     // Save the split loads if there are deferred stores among the users.
46200b57cec5SDimitry Andric     if (DeferredStores)
46210b57cec5SDimitry Andric       SplitLoadsMap.insert(std::make_pair(LI, std::move(SplitLoads)));
46220b57cec5SDimitry Andric 
46230b57cec5SDimitry Andric     // Mark the original load as dead and kill the original slice.
4624e8d8bef9SDimitry Andric     DeadInsts.push_back(LI);
46250b57cec5SDimitry Andric     Offsets.S->kill();
46260b57cec5SDimitry Andric   }
46270b57cec5SDimitry Andric 
46280b57cec5SDimitry Andric   // Second, we rewrite all of the split stores. At this point, we know that
46290b57cec5SDimitry Andric   // all loads from this alloca have been split already. For stores of such
46300b57cec5SDimitry Andric   // loads, we can simply look up the pre-existing split loads. For stores of
46310b57cec5SDimitry Andric   // other loads, we split those loads first and then write split stores of
46320b57cec5SDimitry Andric   // them.
46330b57cec5SDimitry Andric   for (StoreInst *SI : Stores) {
46340b57cec5SDimitry Andric     auto *LI = cast<LoadInst>(SI->getValueOperand());
46350b57cec5SDimitry Andric     IntegerType *Ty = cast<IntegerType>(LI->getType());
4636fe6060f1SDimitry Andric     assert(Ty->getBitWidth() % 8 == 0);
46370b57cec5SDimitry Andric     uint64_t StoreSize = Ty->getBitWidth() / 8;
46380b57cec5SDimitry Andric     assert(StoreSize > 0 && "Cannot have a zero-sized integer store!");
46390b57cec5SDimitry Andric 
46400b57cec5SDimitry Andric     auto &Offsets = SplitOffsetsMap[SI];
46410b57cec5SDimitry Andric     assert(StoreSize == Offsets.S->endOffset() - Offsets.S->beginOffset() &&
46420b57cec5SDimitry Andric            "Slice size should always match load size exactly!");
46430b57cec5SDimitry Andric     uint64_t BaseOffset = Offsets.S->beginOffset();
46440b57cec5SDimitry Andric     assert(BaseOffset + StoreSize > BaseOffset &&
46450b57cec5SDimitry Andric            "Cannot represent alloca access size using 64-bit integers!");
46460b57cec5SDimitry Andric 
46470b57cec5SDimitry Andric     Value *LoadBasePtr = LI->getPointerOperand();
46480b57cec5SDimitry Andric     Instruction *StoreBasePtr = cast<Instruction>(SI->getPointerOperand());
46490b57cec5SDimitry Andric 
46500b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "  Splitting store: " << *SI << "\n");
46510b57cec5SDimitry Andric 
46520b57cec5SDimitry Andric     // Check whether we have an already split load.
46530b57cec5SDimitry Andric     auto SplitLoadsMapI = SplitLoadsMap.find(LI);
46540b57cec5SDimitry Andric     std::vector<LoadInst *> *SplitLoads = nullptr;
46550b57cec5SDimitry Andric     if (SplitLoadsMapI != SplitLoadsMap.end()) {
46560b57cec5SDimitry Andric       SplitLoads = &SplitLoadsMapI->second;
46570b57cec5SDimitry Andric       assert(SplitLoads->size() == Offsets.Splits.size() + 1 &&
46580b57cec5SDimitry Andric              "Too few split loads for the number of splits in the store!");
46590b57cec5SDimitry Andric     } else {
46600b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "          of load: " << *LI << "\n");
46610b57cec5SDimitry Andric     }
46620b57cec5SDimitry Andric 
46630b57cec5SDimitry Andric     uint64_t PartOffset = 0, PartSize = Offsets.Splits.front();
46640b57cec5SDimitry Andric     int Idx = 0, Size = Offsets.Splits.size();
46650b57cec5SDimitry Andric     for (;;) {
46660b57cec5SDimitry Andric       auto *PartTy = Type::getIntNTy(Ty->getContext(), PartSize * 8);
46675f757f3fSDimitry Andric       auto *LoadPartPtrTy = LI->getPointerOperandType();
46685f757f3fSDimitry Andric       auto *StorePartPtrTy = SI->getPointerOperandType();
46690b57cec5SDimitry Andric 
46700b57cec5SDimitry Andric       // Either lookup a split load or create one.
46710b57cec5SDimitry Andric       LoadInst *PLoad;
46720b57cec5SDimitry Andric       if (SplitLoads) {
46730b57cec5SDimitry Andric         PLoad = (*SplitLoads)[Idx];
46740b57cec5SDimitry Andric       } else {
46750b57cec5SDimitry Andric         IRB.SetInsertPoint(LI);
46760b57cec5SDimitry Andric         auto AS = LI->getPointerAddressSpace();
46770b57cec5SDimitry Andric         PLoad = IRB.CreateAlignedLoad(
46780b57cec5SDimitry Andric             PartTy,
46790b57cec5SDimitry Andric             getAdjustedPtr(IRB, DL, LoadBasePtr,
46800b57cec5SDimitry Andric                            APInt(DL.getIndexSizeInBits(AS), PartOffset),
46810b57cec5SDimitry Andric                            LoadPartPtrTy, LoadBasePtr->getName() + "."),
46825ffd83dbSDimitry Andric             getAdjustedAlignment(LI, PartOffset),
4683480093f4SDimitry Andric             /*IsVolatile*/ false, LI->getName());
4684fe6060f1SDimitry Andric         PLoad->copyMetadata(*LI, {LLVMContext::MD_mem_parallel_loop_access,
4685fe6060f1SDimitry Andric                                   LLVMContext::MD_access_group});
46860b57cec5SDimitry Andric       }
46870b57cec5SDimitry Andric 
46880b57cec5SDimitry Andric       // And store this partition.
46890b57cec5SDimitry Andric       IRB.SetInsertPoint(SI);
46900b57cec5SDimitry Andric       auto AS = SI->getPointerAddressSpace();
46910b57cec5SDimitry Andric       StoreInst *PStore = IRB.CreateAlignedStore(
46920b57cec5SDimitry Andric           PLoad,
46930b57cec5SDimitry Andric           getAdjustedPtr(IRB, DL, StoreBasePtr,
46940b57cec5SDimitry Andric                          APInt(DL.getIndexSizeInBits(AS), PartOffset),
46950b57cec5SDimitry Andric                          StorePartPtrTy, StoreBasePtr->getName() + "."),
46965ffd83dbSDimitry Andric           getAdjustedAlignment(SI, PartOffset),
4697480093f4SDimitry Andric           /*IsVolatile*/ false);
4698fe6060f1SDimitry Andric       PStore->copyMetadata(*SI, {LLVMContext::MD_mem_parallel_loop_access,
4699fe6060f1SDimitry Andric                                  LLVMContext::MD_access_group});
47000b57cec5SDimitry Andric 
47010b57cec5SDimitry Andric       // Now build a new slice for the alloca.
47020b57cec5SDimitry Andric       NewSlices.push_back(
47030b57cec5SDimitry Andric           Slice(BaseOffset + PartOffset, BaseOffset + PartOffset + PartSize,
47040b57cec5SDimitry Andric                 &PStore->getOperandUse(PStore->getPointerOperandIndex()),
47050b57cec5SDimitry Andric                 /*IsSplittable*/ false));
47060b57cec5SDimitry Andric       LLVM_DEBUG(dbgs() << "    new slice [" << NewSlices.back().beginOffset()
47070b57cec5SDimitry Andric                         << ", " << NewSlices.back().endOffset()
47080b57cec5SDimitry Andric                         << "): " << *PStore << "\n");
47090b57cec5SDimitry Andric       if (!SplitLoads) {
47100b57cec5SDimitry Andric         LLVM_DEBUG(dbgs() << "      of split load: " << *PLoad << "\n");
47110b57cec5SDimitry Andric       }
47120b57cec5SDimitry Andric 
47130b57cec5SDimitry Andric       // See if we've finished all the splits.
47140b57cec5SDimitry Andric       if (Idx >= Size)
47150b57cec5SDimitry Andric         break;
47160b57cec5SDimitry Andric 
47170b57cec5SDimitry Andric       // Setup the next partition.
47180b57cec5SDimitry Andric       PartOffset = Offsets.Splits[Idx];
47190b57cec5SDimitry Andric       ++Idx;
47200b57cec5SDimitry Andric       PartSize = (Idx < Size ? Offsets.Splits[Idx] : StoreSize) - PartOffset;
47210b57cec5SDimitry Andric     }
47220b57cec5SDimitry Andric 
47230b57cec5SDimitry Andric     // We want to immediately iterate on any allocas impacted by splitting
47240b57cec5SDimitry Andric     // this load, which is only relevant if it isn't a load of this alloca and
47250b57cec5SDimitry Andric     // thus we didn't already split the loads above. We also have to keep track
47260b57cec5SDimitry Andric     // of any promotable allocas we split loads on as they can no longer be
47270b57cec5SDimitry Andric     // promoted.
47280b57cec5SDimitry Andric     if (!SplitLoads) {
47290b57cec5SDimitry Andric       if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(LoadBasePtr)) {
47300b57cec5SDimitry Andric         assert(OtherAI != &AI && "We can't re-split our own alloca!");
47310b57cec5SDimitry Andric         ResplitPromotableAllocas.insert(OtherAI);
47320b57cec5SDimitry Andric         Worklist.insert(OtherAI);
47330b57cec5SDimitry Andric       } else if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(
47340b57cec5SDimitry Andric                      LoadBasePtr->stripInBoundsOffsets())) {
47350b57cec5SDimitry Andric         assert(OtherAI != &AI && "We can't re-split our own alloca!");
47360b57cec5SDimitry Andric         Worklist.insert(OtherAI);
47370b57cec5SDimitry Andric       }
47380b57cec5SDimitry Andric     }
47390b57cec5SDimitry Andric 
47400b57cec5SDimitry Andric     // Mark the original store as dead now that we've split it up and kill its
47410b57cec5SDimitry Andric     // slice. Note that we leave the original load in place unless this store
47420b57cec5SDimitry Andric     // was its only use. It may in turn be split up if it is an alloca load
47430b57cec5SDimitry Andric     // for some other alloca, but it may be a normal load. This may introduce
47440b57cec5SDimitry Andric     // redundant loads, but where those can be merged the rest of the optimizer
47450b57cec5SDimitry Andric     // should handle the merging, and this uncovers SSA splits which is more
47460b57cec5SDimitry Andric     // important. In practice, the original loads will almost always be fully
47470b57cec5SDimitry Andric     // split and removed eventually, and the splits will be merged by any
47480b57cec5SDimitry Andric     // trivial CSE, including instcombine.
47490b57cec5SDimitry Andric     if (LI->hasOneUse()) {
47500b57cec5SDimitry Andric       assert(*LI->user_begin() == SI && "Single use isn't this store!");
4751e8d8bef9SDimitry Andric       DeadInsts.push_back(LI);
47520b57cec5SDimitry Andric     }
4753e8d8bef9SDimitry Andric     DeadInsts.push_back(SI);
47540b57cec5SDimitry Andric     Offsets.S->kill();
47550b57cec5SDimitry Andric   }
47560b57cec5SDimitry Andric 
47570b57cec5SDimitry Andric   // Remove the killed slices that have ben pre-split.
4758e8d8bef9SDimitry Andric   llvm::erase_if(AS, [](const Slice &S) { return S.isDead(); });
47590b57cec5SDimitry Andric 
47600b57cec5SDimitry Andric   // Insert our new slices. This will sort and merge them into the sorted
47610b57cec5SDimitry Andric   // sequence.
47620b57cec5SDimitry Andric   AS.insert(NewSlices);
47630b57cec5SDimitry Andric 
47640b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "  Pre-split slices:\n");
47650b57cec5SDimitry Andric #ifndef NDEBUG
47660b57cec5SDimitry Andric   for (auto I = AS.begin(), E = AS.end(); I != E; ++I)
47670b57cec5SDimitry Andric     LLVM_DEBUG(AS.print(dbgs(), I, "    "));
47680b57cec5SDimitry Andric #endif
47690b57cec5SDimitry Andric 
47700b57cec5SDimitry Andric   // Finally, don't try to promote any allocas that new require re-splitting.
47710b57cec5SDimitry Andric   // They have already been added to the worklist above.
4772e8d8bef9SDimitry Andric   llvm::erase_if(PromotableAllocas, [&](AllocaInst *AI) {
4773e8d8bef9SDimitry Andric     return ResplitPromotableAllocas.count(AI);
4774e8d8bef9SDimitry Andric   });
47750b57cec5SDimitry Andric 
47760b57cec5SDimitry Andric   return true;
47770b57cec5SDimitry Andric }
47780b57cec5SDimitry Andric 
47790b57cec5SDimitry Andric /// Rewrite an alloca partition's users.
47800b57cec5SDimitry Andric ///
47810b57cec5SDimitry Andric /// This routine drives both of the rewriting goals of the SROA pass. It tries
47820b57cec5SDimitry Andric /// to rewrite uses of an alloca partition to be conducive for SSA value
47830b57cec5SDimitry Andric /// promotion. If the partition needs a new, more refined alloca, this will
47840b57cec5SDimitry Andric /// build that new alloca, preserving as much type information as possible, and
47850b57cec5SDimitry Andric /// rewrite the uses of the old alloca to point at the new one and have the
47860b57cec5SDimitry Andric /// appropriate new offsets. It also evaluates how successful the rewrite was
47870b57cec5SDimitry Andric /// at enabling promotion and if it was successful queues the alloca to be
47880b57cec5SDimitry Andric /// promoted.
47895f757f3fSDimitry Andric AllocaInst *SROA::rewritePartition(AllocaInst &AI, AllocaSlices &AS,
47900b57cec5SDimitry Andric                                    Partition &P) {
47910b57cec5SDimitry Andric   // Try to compute a friendly type for this partition of the alloca. This
47920b57cec5SDimitry Andric   // won't always succeed, in which case we fall back to a legal integer type
47930b57cec5SDimitry Andric   // or an i8 array of an appropriate size.
47940b57cec5SDimitry Andric   Type *SliceTy = nullptr;
4795bdd1243dSDimitry Andric   VectorType *SliceVecTy = nullptr;
4796*0fca6ea1SDimitry Andric   const DataLayout &DL = AI.getDataLayout();
4797e8d8bef9SDimitry Andric   std::pair<Type *, IntegerType *> CommonUseTy =
4798e8d8bef9SDimitry Andric       findCommonType(P.begin(), P.end(), P.endOffset());
4799e8d8bef9SDimitry Andric   // Do all uses operate on the same type?
4800e8d8bef9SDimitry Andric   if (CommonUseTy.first)
4801bdd1243dSDimitry Andric     if (DL.getTypeAllocSize(CommonUseTy.first).getFixedValue() >= P.size()) {
4802e8d8bef9SDimitry Andric       SliceTy = CommonUseTy.first;
4803bdd1243dSDimitry Andric       SliceVecTy = dyn_cast<VectorType>(SliceTy);
4804bdd1243dSDimitry Andric     }
4805e8d8bef9SDimitry Andric   // If not, can we find an appropriate subtype in the original allocated type?
48060b57cec5SDimitry Andric   if (!SliceTy)
48070b57cec5SDimitry Andric     if (Type *TypePartitionTy = getTypePartition(DL, AI.getAllocatedType(),
48080b57cec5SDimitry Andric                                                  P.beginOffset(), P.size()))
48090b57cec5SDimitry Andric       SliceTy = TypePartitionTy;
4810bdd1243dSDimitry Andric 
4811e8d8bef9SDimitry Andric   // If still not, can we use the largest bitwidth integer type used?
4812e8d8bef9SDimitry Andric   if (!SliceTy && CommonUseTy.second)
4813bdd1243dSDimitry Andric     if (DL.getTypeAllocSize(CommonUseTy.second).getFixedValue() >= P.size()) {
4814e8d8bef9SDimitry Andric       SliceTy = CommonUseTy.second;
4815bdd1243dSDimitry Andric       SliceVecTy = dyn_cast<VectorType>(SliceTy);
4816bdd1243dSDimitry Andric     }
48170b57cec5SDimitry Andric   if ((!SliceTy || (SliceTy->isArrayTy() &&
48180b57cec5SDimitry Andric                     SliceTy->getArrayElementType()->isIntegerTy())) &&
4819bdd1243dSDimitry Andric       DL.isLegalInteger(P.size() * 8)) {
48200b57cec5SDimitry Andric     SliceTy = Type::getIntNTy(*C, P.size() * 8);
4821bdd1243dSDimitry Andric   }
4822bdd1243dSDimitry Andric 
4823bdd1243dSDimitry Andric   // If the common use types are not viable for promotion then attempt to find
4824bdd1243dSDimitry Andric   // another type that is viable.
4825bdd1243dSDimitry Andric   if (SliceVecTy && !checkVectorTypeForPromotion(P, SliceVecTy, DL))
4826bdd1243dSDimitry Andric     if (Type *TypePartitionTy = getTypePartition(DL, AI.getAllocatedType(),
4827bdd1243dSDimitry Andric                                                  P.beginOffset(), P.size())) {
4828bdd1243dSDimitry Andric       VectorType *TypePartitionVecTy = dyn_cast<VectorType>(TypePartitionTy);
4829bdd1243dSDimitry Andric       if (TypePartitionVecTy &&
4830bdd1243dSDimitry Andric           checkVectorTypeForPromotion(P, TypePartitionVecTy, DL))
4831bdd1243dSDimitry Andric         SliceTy = TypePartitionTy;
4832bdd1243dSDimitry Andric     }
4833bdd1243dSDimitry Andric 
48340b57cec5SDimitry Andric   if (!SliceTy)
48350b57cec5SDimitry Andric     SliceTy = ArrayType::get(Type::getInt8Ty(*C), P.size());
4836bdd1243dSDimitry Andric   assert(DL.getTypeAllocSize(SliceTy).getFixedValue() >= P.size());
48370b57cec5SDimitry Andric 
48380b57cec5SDimitry Andric   bool IsIntegerPromotable = isIntegerWideningViable(P, SliceTy, DL);
48390b57cec5SDimitry Andric 
48400b57cec5SDimitry Andric   VectorType *VecTy =
48410b57cec5SDimitry Andric       IsIntegerPromotable ? nullptr : isVectorPromotionViable(P, DL);
48420b57cec5SDimitry Andric   if (VecTy)
48430b57cec5SDimitry Andric     SliceTy = VecTy;
48440b57cec5SDimitry Andric 
48450b57cec5SDimitry Andric   // Check for the case where we're going to rewrite to a new alloca of the
48460b57cec5SDimitry Andric   // exact same type as the original, and with the same access offsets. In that
48470b57cec5SDimitry Andric   // case, re-use the existing alloca, but still run through the rewriter to
48480b57cec5SDimitry Andric   // perform phi and select speculation.
48490b57cec5SDimitry Andric   // P.beginOffset() can be non-zero even with the same type in a case with
48500b57cec5SDimitry Andric   // out-of-bounds access (e.g. @PR35657 function in SROA/basictest.ll).
48510b57cec5SDimitry Andric   AllocaInst *NewAI;
48520b57cec5SDimitry Andric   if (SliceTy == AI.getAllocatedType() && P.beginOffset() == 0) {
48530b57cec5SDimitry Andric     NewAI = &AI;
48540b57cec5SDimitry Andric     // FIXME: We should be able to bail at this point with "nothing changed".
48550b57cec5SDimitry Andric     // FIXME: We might want to defer PHI speculation until after here.
48560b57cec5SDimitry Andric     // FIXME: return nullptr;
48570b57cec5SDimitry Andric   } else {
48585ffd83dbSDimitry Andric     // Make sure the alignment is compatible with P.beginOffset().
48595ffd83dbSDimitry Andric     const Align Alignment = commonAlignment(AI.getAlign(), P.beginOffset());
48600b57cec5SDimitry Andric     // If we will get at least this much alignment from the type alone, leave
48610b57cec5SDimitry Andric     // the alloca's alignment unconstrained.
48625ffd83dbSDimitry Andric     const bool IsUnconstrained = Alignment <= DL.getABITypeAlign(SliceTy);
48630b57cec5SDimitry Andric     NewAI = new AllocaInst(
4864bdd1243dSDimitry Andric         SliceTy, AI.getAddressSpace(), nullptr,
48655ffd83dbSDimitry Andric         IsUnconstrained ? DL.getPrefTypeAlign(SliceTy) : Alignment,
4866*0fca6ea1SDimitry Andric         AI.getName() + ".sroa." + Twine(P.begin() - AS.begin()),
4867*0fca6ea1SDimitry Andric         AI.getIterator());
48680b57cec5SDimitry Andric     // Copy the old AI debug location over to the new one.
48690b57cec5SDimitry Andric     NewAI->setDebugLoc(AI.getDebugLoc());
48700b57cec5SDimitry Andric     ++NumNewAllocas;
48710b57cec5SDimitry Andric   }
48720b57cec5SDimitry Andric 
4873*0fca6ea1SDimitry Andric   LLVM_DEBUG(dbgs() << "Rewriting alloca partition " << "[" << P.beginOffset()
4874*0fca6ea1SDimitry Andric                     << "," << P.endOffset() << ") to: " << *NewAI << "\n");
48750b57cec5SDimitry Andric 
48760b57cec5SDimitry Andric   // Track the high watermark on the worklist as it is only relevant for
48770b57cec5SDimitry Andric   // promoted allocas. We will reset it to this point if the alloca is not in
48780b57cec5SDimitry Andric   // fact scheduled for promotion.
48790b57cec5SDimitry Andric   unsigned PPWOldSize = PostPromotionWorklist.size();
48800b57cec5SDimitry Andric   unsigned NumUses = 0;
48810b57cec5SDimitry Andric   SmallSetVector<PHINode *, 8> PHIUsers;
48820b57cec5SDimitry Andric   SmallSetVector<SelectInst *, 8> SelectUsers;
48830b57cec5SDimitry Andric 
48840b57cec5SDimitry Andric   AllocaSliceRewriter Rewriter(DL, AS, *this, AI, *NewAI, P.beginOffset(),
48850b57cec5SDimitry Andric                                P.endOffset(), IsIntegerPromotable, VecTy,
48860b57cec5SDimitry Andric                                PHIUsers, SelectUsers);
48870b57cec5SDimitry Andric   bool Promotable = true;
48880b57cec5SDimitry Andric   for (Slice *S : P.splitSliceTails()) {
48890b57cec5SDimitry Andric     Promotable &= Rewriter.visit(S);
48900b57cec5SDimitry Andric     ++NumUses;
48910b57cec5SDimitry Andric   }
48920b57cec5SDimitry Andric   for (Slice &S : P) {
48930b57cec5SDimitry Andric     Promotable &= Rewriter.visit(&S);
48940b57cec5SDimitry Andric     ++NumUses;
48950b57cec5SDimitry Andric   }
48960b57cec5SDimitry Andric 
48970b57cec5SDimitry Andric   NumAllocaPartitionUses += NumUses;
48980b57cec5SDimitry Andric   MaxUsesPerAllocaPartition.updateMax(NumUses);
48990b57cec5SDimitry Andric 
49000b57cec5SDimitry Andric   // Now that we've processed all the slices in the new partition, check if any
49010b57cec5SDimitry Andric   // PHIs or Selects would block promotion.
49020b57cec5SDimitry Andric   for (PHINode *PHI : PHIUsers)
49030b57cec5SDimitry Andric     if (!isSafePHIToSpeculate(*PHI)) {
49040b57cec5SDimitry Andric       Promotable = false;
49050b57cec5SDimitry Andric       PHIUsers.clear();
49060b57cec5SDimitry Andric       SelectUsers.clear();
49070b57cec5SDimitry Andric       break;
49080b57cec5SDimitry Andric     }
49090b57cec5SDimitry Andric 
4910bdd1243dSDimitry Andric   SmallVector<std::pair<SelectInst *, RewriteableMemOps>, 2>
4911bdd1243dSDimitry Andric       NewSelectsToRewrite;
4912bdd1243dSDimitry Andric   NewSelectsToRewrite.reserve(SelectUsers.size());
4913bdd1243dSDimitry Andric   for (SelectInst *Sel : SelectUsers) {
4914bdd1243dSDimitry Andric     std::optional<RewriteableMemOps> Ops =
4915bdd1243dSDimitry Andric         isSafeSelectToSpeculate(*Sel, PreserveCFG);
4916bdd1243dSDimitry Andric     if (!Ops) {
49170b57cec5SDimitry Andric       Promotable = false;
49180b57cec5SDimitry Andric       PHIUsers.clear();
49190b57cec5SDimitry Andric       SelectUsers.clear();
4920bdd1243dSDimitry Andric       NewSelectsToRewrite.clear();
49210b57cec5SDimitry Andric       break;
49220b57cec5SDimitry Andric     }
4923bdd1243dSDimitry Andric     NewSelectsToRewrite.emplace_back(std::make_pair(Sel, *Ops));
4924bdd1243dSDimitry Andric   }
49250b57cec5SDimitry Andric 
49260b57cec5SDimitry Andric   if (Promotable) {
4927e8d8bef9SDimitry Andric     for (Use *U : AS.getDeadUsesIfPromotable()) {
4928e8d8bef9SDimitry Andric       auto *OldInst = dyn_cast<Instruction>(U->get());
4929e8d8bef9SDimitry Andric       Value::dropDroppableUse(*U);
4930e8d8bef9SDimitry Andric       if (OldInst)
4931e8d8bef9SDimitry Andric         if (isInstructionTriviallyDead(OldInst))
4932e8d8bef9SDimitry Andric           DeadInsts.push_back(OldInst);
4933e8d8bef9SDimitry Andric     }
49340b57cec5SDimitry Andric     if (PHIUsers.empty() && SelectUsers.empty()) {
49350b57cec5SDimitry Andric       // Promote the alloca.
49360b57cec5SDimitry Andric       PromotableAllocas.push_back(NewAI);
49370b57cec5SDimitry Andric     } else {
49380b57cec5SDimitry Andric       // If we have either PHIs or Selects to speculate, add them to those
49390b57cec5SDimitry Andric       // worklists and re-queue the new alloca so that we promote in on the
49400b57cec5SDimitry Andric       // next iteration.
49410b57cec5SDimitry Andric       for (PHINode *PHIUser : PHIUsers)
49420b57cec5SDimitry Andric         SpeculatablePHIs.insert(PHIUser);
4943bdd1243dSDimitry Andric       SelectsToRewrite.reserve(SelectsToRewrite.size() +
4944bdd1243dSDimitry Andric                                NewSelectsToRewrite.size());
4945bdd1243dSDimitry Andric       for (auto &&KV : llvm::make_range(
4946bdd1243dSDimitry Andric                std::make_move_iterator(NewSelectsToRewrite.begin()),
4947bdd1243dSDimitry Andric                std::make_move_iterator(NewSelectsToRewrite.end())))
4948bdd1243dSDimitry Andric         SelectsToRewrite.insert(std::move(KV));
49490b57cec5SDimitry Andric       Worklist.insert(NewAI);
49500b57cec5SDimitry Andric     }
49510b57cec5SDimitry Andric   } else {
49520b57cec5SDimitry Andric     // Drop any post-promotion work items if promotion didn't happen.
49530b57cec5SDimitry Andric     while (PostPromotionWorklist.size() > PPWOldSize)
49540b57cec5SDimitry Andric       PostPromotionWorklist.pop_back();
49550b57cec5SDimitry Andric 
49560b57cec5SDimitry Andric     // We couldn't promote and we didn't create a new partition, nothing
49570b57cec5SDimitry Andric     // happened.
49580b57cec5SDimitry Andric     if (NewAI == &AI)
49590b57cec5SDimitry Andric       return nullptr;
49600b57cec5SDimitry Andric 
49610b57cec5SDimitry Andric     // If we can't promote the alloca, iterate on it to check for new
49620b57cec5SDimitry Andric     // refinements exposed by splitting the current alloca. Don't iterate on an
49630b57cec5SDimitry Andric     // alloca which didn't actually change and didn't get promoted.
49640b57cec5SDimitry Andric     Worklist.insert(NewAI);
49650b57cec5SDimitry Andric   }
49660b57cec5SDimitry Andric 
49670b57cec5SDimitry Andric   return NewAI;
49680b57cec5SDimitry Andric }
49690b57cec5SDimitry Andric 
4970*0fca6ea1SDimitry Andric // There isn't a shared interface to get the "address" parts out of a
4971*0fca6ea1SDimitry Andric // dbg.declare and dbg.assign, so provide some wrappers now for
4972*0fca6ea1SDimitry Andric // both debug intrinsics and records.
4973*0fca6ea1SDimitry Andric const Value *getAddress(const DbgVariableIntrinsic *DVI) {
4974*0fca6ea1SDimitry Andric   if (const auto *DAI = dyn_cast<DbgAssignIntrinsic>(DVI))
4975*0fca6ea1SDimitry Andric     return DAI->getAddress();
4976*0fca6ea1SDimitry Andric   return cast<DbgDeclareInst>(DVI)->getAddress();
4977*0fca6ea1SDimitry Andric }
4978*0fca6ea1SDimitry Andric 
4979*0fca6ea1SDimitry Andric const Value *getAddress(const DbgVariableRecord *DVR) {
4980*0fca6ea1SDimitry Andric   assert(DVR->getType() == DbgVariableRecord::LocationType::Declare ||
4981*0fca6ea1SDimitry Andric          DVR->getType() == DbgVariableRecord::LocationType::Assign);
4982*0fca6ea1SDimitry Andric   return DVR->getAddress();
4983*0fca6ea1SDimitry Andric }
4984*0fca6ea1SDimitry Andric 
4985*0fca6ea1SDimitry Andric bool isKillAddress(const DbgVariableIntrinsic *DVI) {
4986*0fca6ea1SDimitry Andric   if (const auto *DAI = dyn_cast<DbgAssignIntrinsic>(DVI))
4987*0fca6ea1SDimitry Andric     return DAI->isKillAddress();
4988*0fca6ea1SDimitry Andric   return cast<DbgDeclareInst>(DVI)->isKillLocation();
4989*0fca6ea1SDimitry Andric }
4990*0fca6ea1SDimitry Andric 
4991*0fca6ea1SDimitry Andric bool isKillAddress(const DbgVariableRecord *DVR) {
4992*0fca6ea1SDimitry Andric   assert(DVR->getType() == DbgVariableRecord::LocationType::Declare ||
4993*0fca6ea1SDimitry Andric          DVR->getType() == DbgVariableRecord::LocationType::Assign);
4994*0fca6ea1SDimitry Andric   if (DVR->getType() == DbgVariableRecord::LocationType::Assign)
4995*0fca6ea1SDimitry Andric     return DVR->isKillAddress();
4996*0fca6ea1SDimitry Andric   return DVR->isKillLocation();
4997*0fca6ea1SDimitry Andric }
4998*0fca6ea1SDimitry Andric 
4999*0fca6ea1SDimitry Andric const DIExpression *getAddressExpression(const DbgVariableIntrinsic *DVI) {
5000*0fca6ea1SDimitry Andric   if (const auto *DAI = dyn_cast<DbgAssignIntrinsic>(DVI))
5001*0fca6ea1SDimitry Andric     return DAI->getAddressExpression();
5002*0fca6ea1SDimitry Andric   return cast<DbgDeclareInst>(DVI)->getExpression();
5003*0fca6ea1SDimitry Andric }
5004*0fca6ea1SDimitry Andric 
5005*0fca6ea1SDimitry Andric const DIExpression *getAddressExpression(const DbgVariableRecord *DVR) {
5006*0fca6ea1SDimitry Andric   assert(DVR->getType() == DbgVariableRecord::LocationType::Declare ||
5007*0fca6ea1SDimitry Andric          DVR->getType() == DbgVariableRecord::LocationType::Assign);
5008*0fca6ea1SDimitry Andric   if (DVR->getType() == DbgVariableRecord::LocationType::Assign)
5009*0fca6ea1SDimitry Andric     return DVR->getAddressExpression();
5010*0fca6ea1SDimitry Andric   return DVR->getExpression();
5011*0fca6ea1SDimitry Andric }
5012*0fca6ea1SDimitry Andric 
5013*0fca6ea1SDimitry Andric /// Create or replace an existing fragment in a DIExpression with \p Frag.
5014*0fca6ea1SDimitry Andric /// If the expression already contains a DW_OP_LLVM_extract_bits_[sz]ext
5015*0fca6ea1SDimitry Andric /// operation, add \p BitExtractOffset to the offset part.
5016*0fca6ea1SDimitry Andric ///
5017*0fca6ea1SDimitry Andric /// Returns the new expression, or nullptr if this fails (see details below).
5018*0fca6ea1SDimitry Andric ///
5019*0fca6ea1SDimitry Andric /// This function is similar to DIExpression::createFragmentExpression except
5020*0fca6ea1SDimitry Andric /// for 3 important distinctions:
5021*0fca6ea1SDimitry Andric ///   1. The new fragment isn't relative to an existing fragment.
5022*0fca6ea1SDimitry Andric ///   2. It assumes the computed location is a memory location. This means we
5023*0fca6ea1SDimitry Andric ///      don't need to perform checks that creating the fragment preserves the
5024*0fca6ea1SDimitry Andric ///      expression semantics.
5025*0fca6ea1SDimitry Andric ///   3. Existing extract_bits are modified independently of fragment changes
5026*0fca6ea1SDimitry Andric ///      using \p BitExtractOffset. A change to the fragment offset or size
5027*0fca6ea1SDimitry Andric ///      may affect a bit extract. But a bit extract offset can change
5028*0fca6ea1SDimitry Andric ///      independently of the fragment dimensions.
5029*0fca6ea1SDimitry Andric ///
5030*0fca6ea1SDimitry Andric /// Returns the new expression, or nullptr if one couldn't be created.
5031*0fca6ea1SDimitry Andric /// Ideally this is only used to signal that a bit-extract has become
5032*0fca6ea1SDimitry Andric /// zero-sized (and thus the new debug record has no size and can be
5033*0fca6ea1SDimitry Andric /// dropped), however, it fails for other reasons too - see the FIXME below.
5034*0fca6ea1SDimitry Andric ///
5035*0fca6ea1SDimitry Andric /// FIXME: To keep the change that introduces this function NFC it bails
5036*0fca6ea1SDimitry Andric /// in some situations unecessarily, e.g. when fragment and bit extract
5037*0fca6ea1SDimitry Andric /// sizes differ.
5038*0fca6ea1SDimitry Andric static DIExpression *createOrReplaceFragment(const DIExpression *Expr,
5039*0fca6ea1SDimitry Andric                                              DIExpression::FragmentInfo Frag,
5040*0fca6ea1SDimitry Andric                                              int64_t BitExtractOffset) {
5041*0fca6ea1SDimitry Andric   SmallVector<uint64_t, 8> Ops;
5042*0fca6ea1SDimitry Andric   bool HasFragment = false;
5043*0fca6ea1SDimitry Andric   bool HasBitExtract = false;
5044*0fca6ea1SDimitry Andric 
5045*0fca6ea1SDimitry Andric   for (auto &Op : Expr->expr_ops()) {
5046*0fca6ea1SDimitry Andric     if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
5047*0fca6ea1SDimitry Andric       HasFragment = true;
5048*0fca6ea1SDimitry Andric       continue;
5049*0fca6ea1SDimitry Andric     }
5050*0fca6ea1SDimitry Andric     if (Op.getOp() == dwarf::DW_OP_LLVM_extract_bits_zext ||
5051*0fca6ea1SDimitry Andric         Op.getOp() == dwarf::DW_OP_LLVM_extract_bits_sext) {
5052*0fca6ea1SDimitry Andric       HasBitExtract = true;
5053*0fca6ea1SDimitry Andric       int64_t ExtractOffsetInBits = Op.getArg(0);
5054*0fca6ea1SDimitry Andric       int64_t ExtractSizeInBits = Op.getArg(1);
5055*0fca6ea1SDimitry Andric 
5056*0fca6ea1SDimitry Andric       // DIExpression::createFragmentExpression doesn't know how to handle
5057*0fca6ea1SDimitry Andric       // a fragment that is smaller than the extract. Copy the behaviour
5058*0fca6ea1SDimitry Andric       // (bail) to avoid non-NFC changes.
5059*0fca6ea1SDimitry Andric       // FIXME: Don't do this.
5060*0fca6ea1SDimitry Andric       if (Frag.SizeInBits < uint64_t(ExtractSizeInBits))
5061*0fca6ea1SDimitry Andric         return nullptr;
5062*0fca6ea1SDimitry Andric 
5063*0fca6ea1SDimitry Andric       assert(BitExtractOffset <= 0);
5064*0fca6ea1SDimitry Andric       int64_t AdjustedOffset = ExtractOffsetInBits + BitExtractOffset;
5065*0fca6ea1SDimitry Andric 
5066*0fca6ea1SDimitry Andric       // DIExpression::createFragmentExpression doesn't know what to do
5067*0fca6ea1SDimitry Andric       // if the new extract starts "outside" the existing one. Copy the
5068*0fca6ea1SDimitry Andric       // behaviour (bail) to avoid non-NFC changes.
5069*0fca6ea1SDimitry Andric       // FIXME: Don't do this.
5070*0fca6ea1SDimitry Andric       if (AdjustedOffset < 0)
5071*0fca6ea1SDimitry Andric         return nullptr;
5072*0fca6ea1SDimitry Andric 
5073*0fca6ea1SDimitry Andric       Ops.push_back(Op.getOp());
5074*0fca6ea1SDimitry Andric       Ops.push_back(std::max<int64_t>(0, AdjustedOffset));
5075*0fca6ea1SDimitry Andric       Ops.push_back(ExtractSizeInBits);
5076*0fca6ea1SDimitry Andric       continue;
5077*0fca6ea1SDimitry Andric     }
5078*0fca6ea1SDimitry Andric     Op.appendToVector(Ops);
5079*0fca6ea1SDimitry Andric   }
5080*0fca6ea1SDimitry Andric 
5081*0fca6ea1SDimitry Andric   // Unsupported by createFragmentExpression, so don't support it here yet to
5082*0fca6ea1SDimitry Andric   // preserve NFC-ness.
5083*0fca6ea1SDimitry Andric   if (HasFragment && HasBitExtract)
5084*0fca6ea1SDimitry Andric     return nullptr;
5085*0fca6ea1SDimitry Andric 
5086*0fca6ea1SDimitry Andric   if (!HasBitExtract) {
5087*0fca6ea1SDimitry Andric     Ops.push_back(dwarf::DW_OP_LLVM_fragment);
5088*0fca6ea1SDimitry Andric     Ops.push_back(Frag.OffsetInBits);
5089*0fca6ea1SDimitry Andric     Ops.push_back(Frag.SizeInBits);
5090*0fca6ea1SDimitry Andric   }
5091*0fca6ea1SDimitry Andric   return DIExpression::get(Expr->getContext(), Ops);
5092*0fca6ea1SDimitry Andric }
5093*0fca6ea1SDimitry Andric 
5094*0fca6ea1SDimitry Andric /// Insert a new dbg.declare.
5095*0fca6ea1SDimitry Andric /// \p Orig Original to copy debug loc and variable from.
5096*0fca6ea1SDimitry Andric /// \p NewAddr Location's new base address.
5097*0fca6ea1SDimitry Andric /// \p NewAddrExpr New expression to apply to address.
5098*0fca6ea1SDimitry Andric /// \p BeforeInst Insert position.
5099*0fca6ea1SDimitry Andric /// \p NewFragment New fragment (absolute, non-relative).
5100*0fca6ea1SDimitry Andric /// \p BitExtractAdjustment Offset to apply to any extract_bits op.
5101*0fca6ea1SDimitry Andric static void
5102*0fca6ea1SDimitry Andric insertNewDbgInst(DIBuilder &DIB, DbgDeclareInst *Orig, AllocaInst *NewAddr,
5103*0fca6ea1SDimitry Andric                  DIExpression *NewAddrExpr, Instruction *BeforeInst,
5104*0fca6ea1SDimitry Andric                  std::optional<DIExpression::FragmentInfo> NewFragment,
5105*0fca6ea1SDimitry Andric                  int64_t BitExtractAdjustment) {
5106*0fca6ea1SDimitry Andric   if (NewFragment)
5107*0fca6ea1SDimitry Andric     NewAddrExpr = createOrReplaceFragment(NewAddrExpr, *NewFragment,
5108*0fca6ea1SDimitry Andric                                           BitExtractAdjustment);
5109*0fca6ea1SDimitry Andric   if (!NewAddrExpr)
5110*0fca6ea1SDimitry Andric     return;
5111*0fca6ea1SDimitry Andric 
5112*0fca6ea1SDimitry Andric   DIB.insertDeclare(NewAddr, Orig->getVariable(), NewAddrExpr,
51135f757f3fSDimitry Andric                     Orig->getDebugLoc(), BeforeInst);
51145f757f3fSDimitry Andric }
5115*0fca6ea1SDimitry Andric 
5116*0fca6ea1SDimitry Andric /// Insert a new dbg.assign.
5117*0fca6ea1SDimitry Andric /// \p Orig Original to copy debug loc, variable, value and value expression
5118*0fca6ea1SDimitry Andric ///    from.
5119*0fca6ea1SDimitry Andric /// \p NewAddr Location's new base address.
5120*0fca6ea1SDimitry Andric /// \p NewAddrExpr New expression to apply to address.
5121*0fca6ea1SDimitry Andric /// \p BeforeInst Insert position.
5122*0fca6ea1SDimitry Andric /// \p NewFragment New fragment (absolute, non-relative).
5123*0fca6ea1SDimitry Andric /// \p BitExtractAdjustment Offset to apply to any extract_bits op.
5124*0fca6ea1SDimitry Andric static void
5125*0fca6ea1SDimitry Andric insertNewDbgInst(DIBuilder &DIB, DbgAssignIntrinsic *Orig, AllocaInst *NewAddr,
5126*0fca6ea1SDimitry Andric                  DIExpression *NewAddrExpr, Instruction *BeforeInst,
5127*0fca6ea1SDimitry Andric                  std::optional<DIExpression::FragmentInfo> NewFragment,
5128*0fca6ea1SDimitry Andric                  int64_t BitExtractAdjustment) {
5129*0fca6ea1SDimitry Andric   // DIBuilder::insertDbgAssign will insert the #dbg_assign after NewAddr.
51305f757f3fSDimitry Andric   (void)BeforeInst;
5131*0fca6ea1SDimitry Andric 
5132*0fca6ea1SDimitry Andric   // A dbg.assign puts fragment info in the value expression only. The address
5133*0fca6ea1SDimitry Andric   // expression has already been built: NewAddrExpr.
5134*0fca6ea1SDimitry Andric   DIExpression *NewFragmentExpr = Orig->getExpression();
5135*0fca6ea1SDimitry Andric   if (NewFragment)
5136*0fca6ea1SDimitry Andric     NewFragmentExpr = createOrReplaceFragment(NewFragmentExpr, *NewFragment,
5137*0fca6ea1SDimitry Andric                                               BitExtractAdjustment);
5138*0fca6ea1SDimitry Andric   if (!NewFragmentExpr)
5139*0fca6ea1SDimitry Andric     return;
5140*0fca6ea1SDimitry Andric 
5141*0fca6ea1SDimitry Andric   // Apply a DIAssignID to the store if it doesn't already have it.
51425f757f3fSDimitry Andric   if (!NewAddr->hasMetadata(LLVMContext::MD_DIAssignID)) {
51435f757f3fSDimitry Andric     NewAddr->setMetadata(LLVMContext::MD_DIAssignID,
51445f757f3fSDimitry Andric                          DIAssignID::getDistinct(NewAddr->getContext()));
51455f757f3fSDimitry Andric   }
5146*0fca6ea1SDimitry Andric 
5147*0fca6ea1SDimitry Andric   Instruction *NewAssign =
5148*0fca6ea1SDimitry Andric       DIB.insertDbgAssign(NewAddr, Orig->getValue(), Orig->getVariable(),
5149*0fca6ea1SDimitry Andric                           NewFragmentExpr, NewAddr, NewAddrExpr,
5150*0fca6ea1SDimitry Andric                           Orig->getDebugLoc())
5151*0fca6ea1SDimitry Andric           .get<Instruction *>();
51525f757f3fSDimitry Andric   LLVM_DEBUG(dbgs() << "Created new assign intrinsic: " << *NewAssign << "\n");
51535f757f3fSDimitry Andric   (void)NewAssign;
51545f757f3fSDimitry Andric }
5155*0fca6ea1SDimitry Andric 
5156*0fca6ea1SDimitry Andric /// Insert a new DbgRecord.
5157*0fca6ea1SDimitry Andric /// \p Orig Original to copy record type, debug loc and variable from, and
5158*0fca6ea1SDimitry Andric ///    additionally value and value expression for dbg_assign records.
5159*0fca6ea1SDimitry Andric /// \p NewAddr Location's new base address.
5160*0fca6ea1SDimitry Andric /// \p NewAddrExpr New expression to apply to address.
5161*0fca6ea1SDimitry Andric /// \p BeforeInst Insert position.
5162*0fca6ea1SDimitry Andric /// \p NewFragment New fragment (absolute, non-relative).
5163*0fca6ea1SDimitry Andric /// \p BitExtractAdjustment Offset to apply to any extract_bits op.
5164*0fca6ea1SDimitry Andric static void
5165*0fca6ea1SDimitry Andric insertNewDbgInst(DIBuilder &DIB, DbgVariableRecord *Orig, AllocaInst *NewAddr,
5166*0fca6ea1SDimitry Andric                  DIExpression *NewAddrExpr, Instruction *BeforeInst,
5167*0fca6ea1SDimitry Andric                  std::optional<DIExpression::FragmentInfo> NewFragment,
5168*0fca6ea1SDimitry Andric                  int64_t BitExtractAdjustment) {
51695f757f3fSDimitry Andric   (void)DIB;
5170*0fca6ea1SDimitry Andric 
5171*0fca6ea1SDimitry Andric   // A dbg_assign puts fragment info in the value expression only. The address
5172*0fca6ea1SDimitry Andric   // expression has already been built: NewAddrExpr. A dbg_declare puts the
5173*0fca6ea1SDimitry Andric   // new fragment info into NewAddrExpr (as it only has one expression).
5174*0fca6ea1SDimitry Andric   DIExpression *NewFragmentExpr =
5175*0fca6ea1SDimitry Andric       Orig->isDbgAssign() ? Orig->getExpression() : NewAddrExpr;
5176*0fca6ea1SDimitry Andric   if (NewFragment)
5177*0fca6ea1SDimitry Andric     NewFragmentExpr = createOrReplaceFragment(NewFragmentExpr, *NewFragment,
5178*0fca6ea1SDimitry Andric                                               BitExtractAdjustment);
5179*0fca6ea1SDimitry Andric   if (!NewFragmentExpr)
5180*0fca6ea1SDimitry Andric     return;
5181*0fca6ea1SDimitry Andric 
51827a6dacacSDimitry Andric   if (Orig->isDbgDeclare()) {
5183*0fca6ea1SDimitry Andric     DbgVariableRecord *DVR = DbgVariableRecord::createDVRDeclare(
51847a6dacacSDimitry Andric         NewAddr, Orig->getVariable(), NewFragmentExpr, Orig->getDebugLoc());
5185*0fca6ea1SDimitry Andric     BeforeInst->getParent()->insertDbgRecordBefore(DVR,
51867a6dacacSDimitry Andric                                                    BeforeInst->getIterator());
51877a6dacacSDimitry Andric     return;
51887a6dacacSDimitry Andric   }
5189*0fca6ea1SDimitry Andric 
5190*0fca6ea1SDimitry Andric   // Apply a DIAssignID to the store if it doesn't already have it.
51917a6dacacSDimitry Andric   if (!NewAddr->hasMetadata(LLVMContext::MD_DIAssignID)) {
51927a6dacacSDimitry Andric     NewAddr->setMetadata(LLVMContext::MD_DIAssignID,
51937a6dacacSDimitry Andric                          DIAssignID::getDistinct(NewAddr->getContext()));
51947a6dacacSDimitry Andric   }
5195*0fca6ea1SDimitry Andric 
5196*0fca6ea1SDimitry Andric   DbgVariableRecord *NewAssign = DbgVariableRecord::createLinkedDVRAssign(
51977a6dacacSDimitry Andric       NewAddr, Orig->getValue(), Orig->getVariable(), NewFragmentExpr, NewAddr,
5198*0fca6ea1SDimitry Andric       NewAddrExpr, Orig->getDebugLoc());
5199*0fca6ea1SDimitry Andric   LLVM_DEBUG(dbgs() << "Created new DVRAssign: " << *NewAssign << "\n");
52007a6dacacSDimitry Andric   (void)NewAssign;
52015f757f3fSDimitry Andric }
52025f757f3fSDimitry Andric 
52030b57cec5SDimitry Andric /// Walks the slices of an alloca and form partitions based on them,
52040b57cec5SDimitry Andric /// rewriting each of their uses.
52055f757f3fSDimitry Andric bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &AS) {
52060b57cec5SDimitry Andric   if (AS.begin() == AS.end())
52070b57cec5SDimitry Andric     return false;
52080b57cec5SDimitry Andric 
52090b57cec5SDimitry Andric   unsigned NumPartitions = 0;
52100b57cec5SDimitry Andric   bool Changed = false;
52110b57cec5SDimitry Andric   const DataLayout &DL = AI.getModule()->getDataLayout();
52120b57cec5SDimitry Andric 
52130b57cec5SDimitry Andric   // First try to pre-split loads and stores.
52140b57cec5SDimitry Andric   Changed |= presplitLoadsAndStores(AI, AS);
52150b57cec5SDimitry Andric 
52160b57cec5SDimitry Andric   // Now that we have identified any pre-splitting opportunities,
52170b57cec5SDimitry Andric   // mark loads and stores unsplittable except for the following case.
52180b57cec5SDimitry Andric   // We leave a slice splittable if all other slices are disjoint or fully
52190b57cec5SDimitry Andric   // included in the slice, such as whole-alloca loads and stores.
52200b57cec5SDimitry Andric   // If we fail to split these during pre-splitting, we want to force them
52210b57cec5SDimitry Andric   // to be rewritten into a partition.
52220b57cec5SDimitry Andric   bool IsSorted = true;
52230b57cec5SDimitry Andric 
52245ffd83dbSDimitry Andric   uint64_t AllocaSize =
5225bdd1243dSDimitry Andric       DL.getTypeAllocSize(AI.getAllocatedType()).getFixedValue();
52260b57cec5SDimitry Andric   const uint64_t MaxBitVectorSize = 1024;
52270b57cec5SDimitry Andric   if (AllocaSize <= MaxBitVectorSize) {
52280b57cec5SDimitry Andric     // If a byte boundary is included in any load or store, a slice starting or
52290b57cec5SDimitry Andric     // ending at the boundary is not splittable.
52300b57cec5SDimitry Andric     SmallBitVector SplittableOffset(AllocaSize + 1, true);
52310b57cec5SDimitry Andric     for (Slice &S : AS)
52320b57cec5SDimitry Andric       for (unsigned O = S.beginOffset() + 1;
52330b57cec5SDimitry Andric            O < S.endOffset() && O < AllocaSize; O++)
52340b57cec5SDimitry Andric         SplittableOffset.reset(O);
52350b57cec5SDimitry Andric 
52360b57cec5SDimitry Andric     for (Slice &S : AS) {
52370b57cec5SDimitry Andric       if (!S.isSplittable())
52380b57cec5SDimitry Andric         continue;
52390b57cec5SDimitry Andric 
52400b57cec5SDimitry Andric       if ((S.beginOffset() > AllocaSize || SplittableOffset[S.beginOffset()]) &&
52410b57cec5SDimitry Andric           (S.endOffset() > AllocaSize || SplittableOffset[S.endOffset()]))
52420b57cec5SDimitry Andric         continue;
52430b57cec5SDimitry Andric 
52440b57cec5SDimitry Andric       if (isa<LoadInst>(S.getUse()->getUser()) ||
52450b57cec5SDimitry Andric           isa<StoreInst>(S.getUse()->getUser())) {
52460b57cec5SDimitry Andric         S.makeUnsplittable();
52470b57cec5SDimitry Andric         IsSorted = false;
52480b57cec5SDimitry Andric       }
52490b57cec5SDimitry Andric     }
5250*0fca6ea1SDimitry Andric   } else {
52510b57cec5SDimitry Andric     // We only allow whole-alloca splittable loads and stores
52520b57cec5SDimitry Andric     // for a large alloca to avoid creating too large BitVector.
52530b57cec5SDimitry Andric     for (Slice &S : AS) {
52540b57cec5SDimitry Andric       if (!S.isSplittable())
52550b57cec5SDimitry Andric         continue;
52560b57cec5SDimitry Andric 
52570b57cec5SDimitry Andric       if (S.beginOffset() == 0 && S.endOffset() >= AllocaSize)
52580b57cec5SDimitry Andric         continue;
52590b57cec5SDimitry Andric 
52600b57cec5SDimitry Andric       if (isa<LoadInst>(S.getUse()->getUser()) ||
52610b57cec5SDimitry Andric           isa<StoreInst>(S.getUse()->getUser())) {
52620b57cec5SDimitry Andric         S.makeUnsplittable();
52630b57cec5SDimitry Andric         IsSorted = false;
52640b57cec5SDimitry Andric       }
52650b57cec5SDimitry Andric     }
52660b57cec5SDimitry Andric   }
52670b57cec5SDimitry Andric 
52680b57cec5SDimitry Andric   if (!IsSorted)
5269*0fca6ea1SDimitry Andric     llvm::stable_sort(AS);
52700b57cec5SDimitry Andric 
52710b57cec5SDimitry Andric   /// Describes the allocas introduced by rewritePartition in order to migrate
52720b57cec5SDimitry Andric   /// the debug info.
52730b57cec5SDimitry Andric   struct Fragment {
52740b57cec5SDimitry Andric     AllocaInst *Alloca;
52750b57cec5SDimitry Andric     uint64_t Offset;
52760b57cec5SDimitry Andric     uint64_t Size;
52770b57cec5SDimitry Andric     Fragment(AllocaInst *AI, uint64_t O, uint64_t S)
52780b57cec5SDimitry Andric         : Alloca(AI), Offset(O), Size(S) {}
52790b57cec5SDimitry Andric   };
52800b57cec5SDimitry Andric   SmallVector<Fragment, 4> Fragments;
52810b57cec5SDimitry Andric 
52820b57cec5SDimitry Andric   // Rewrite each partition.
52830b57cec5SDimitry Andric   for (auto &P : AS.partitions()) {
52840b57cec5SDimitry Andric     if (AllocaInst *NewAI = rewritePartition(AI, AS, P)) {
52850b57cec5SDimitry Andric       Changed = true;
52860b57cec5SDimitry Andric       if (NewAI != &AI) {
52870b57cec5SDimitry Andric         uint64_t SizeOfByte = 8;
52885ffd83dbSDimitry Andric         uint64_t AllocaSize =
5289bdd1243dSDimitry Andric             DL.getTypeSizeInBits(NewAI->getAllocatedType()).getFixedValue();
52900b57cec5SDimitry Andric         // Don't include any padding.
52910b57cec5SDimitry Andric         uint64_t Size = std::min(AllocaSize, P.size() * SizeOfByte);
5292*0fca6ea1SDimitry Andric         Fragments.push_back(
5293*0fca6ea1SDimitry Andric             Fragment(NewAI, P.beginOffset() * SizeOfByte, Size));
52940b57cec5SDimitry Andric       }
52950b57cec5SDimitry Andric     }
52960b57cec5SDimitry Andric     ++NumPartitions;
52970b57cec5SDimitry Andric   }
52980b57cec5SDimitry Andric 
52990b57cec5SDimitry Andric   NumAllocaPartitions += NumPartitions;
53000b57cec5SDimitry Andric   MaxPartitionsPerAlloca.updateMax(NumPartitions);
53010b57cec5SDimitry Andric 
53020b57cec5SDimitry Andric   // Migrate debug information from the old alloca to the new alloca(s)
53030b57cec5SDimitry Andric   // and the individual partitions.
53045f757f3fSDimitry Andric   auto MigrateOne = [&](auto *DbgVariable) {
5305*0fca6ea1SDimitry Andric     // Can't overlap with undef memory.
5306*0fca6ea1SDimitry Andric     if (isKillAddress(DbgVariable))
5307*0fca6ea1SDimitry Andric       return;
5308*0fca6ea1SDimitry Andric 
5309*0fca6ea1SDimitry Andric     const Value *DbgPtr = getAddress(DbgVariable);
5310*0fca6ea1SDimitry Andric     DIExpression::FragmentInfo VarFrag =
5311*0fca6ea1SDimitry Andric         DbgVariable->getFragmentOrEntireVariable();
5312*0fca6ea1SDimitry Andric     // Get the address expression constant offset if one exists and the ops
5313*0fca6ea1SDimitry Andric     // that come after it.
5314*0fca6ea1SDimitry Andric     int64_t CurrentExprOffsetInBytes = 0;
5315*0fca6ea1SDimitry Andric     SmallVector<uint64_t> PostOffsetOps;
5316*0fca6ea1SDimitry Andric     if (!getAddressExpression(DbgVariable)
5317*0fca6ea1SDimitry Andric              ->extractLeadingOffset(CurrentExprOffsetInBytes, PostOffsetOps))
5318*0fca6ea1SDimitry Andric       return; // Couldn't interpret this DIExpression - drop the var.
5319*0fca6ea1SDimitry Andric 
5320*0fca6ea1SDimitry Andric     // Offset defined by a DW_OP_LLVM_extract_bits_[sz]ext.
5321*0fca6ea1SDimitry Andric     int64_t ExtractOffsetInBits = 0;
5322*0fca6ea1SDimitry Andric     for (auto Op : getAddressExpression(DbgVariable)->expr_ops()) {
5323*0fca6ea1SDimitry Andric       if (Op.getOp() == dwarf::DW_OP_LLVM_extract_bits_zext ||
5324*0fca6ea1SDimitry Andric           Op.getOp() == dwarf::DW_OP_LLVM_extract_bits_sext) {
5325*0fca6ea1SDimitry Andric         ExtractOffsetInBits = Op.getArg(0);
5326*0fca6ea1SDimitry Andric         break;
5327*0fca6ea1SDimitry Andric       }
5328*0fca6ea1SDimitry Andric     }
5329*0fca6ea1SDimitry Andric 
53300b57cec5SDimitry Andric     DIBuilder DIB(*AI.getModule(), /*AllowUnresolved*/ false);
53310b57cec5SDimitry Andric     for (auto Fragment : Fragments) {
5332*0fca6ea1SDimitry Andric       int64_t OffsetFromLocationInBits;
5333*0fca6ea1SDimitry Andric       std::optional<DIExpression::FragmentInfo> NewDbgFragment;
5334*0fca6ea1SDimitry Andric       // Find the variable fragment that the new alloca slice covers.
5335*0fca6ea1SDimitry Andric       // Drop debug info for this variable fragment if we can't compute an
5336*0fca6ea1SDimitry Andric       // intersect between it and the alloca slice.
5337*0fca6ea1SDimitry Andric       if (!DIExpression::calculateFragmentIntersect(
5338*0fca6ea1SDimitry Andric               DL, &AI, Fragment.Offset, Fragment.Size, DbgPtr,
5339*0fca6ea1SDimitry Andric               CurrentExprOffsetInBytes * 8, ExtractOffsetInBits, VarFrag,
5340*0fca6ea1SDimitry Andric               NewDbgFragment, OffsetFromLocationInBits))
5341*0fca6ea1SDimitry Andric         continue; // Do not migrate this fragment to this slice.
53420b57cec5SDimitry Andric 
5343*0fca6ea1SDimitry Andric       // Zero sized fragment indicates there's no intersect between the variable
5344*0fca6ea1SDimitry Andric       // fragment and the alloca slice. Skip this slice for this variable
5345*0fca6ea1SDimitry Andric       // fragment.
5346*0fca6ea1SDimitry Andric       if (NewDbgFragment && !NewDbgFragment->SizeInBits)
5347*0fca6ea1SDimitry Andric         continue; // Do not migrate this fragment to this slice.
53480b57cec5SDimitry Andric 
5349*0fca6ea1SDimitry Andric       // No fragment indicates DbgVariable's variable or fragment exactly
5350*0fca6ea1SDimitry Andric       // overlaps the slice; copy its fragment (or nullopt if there isn't one).
5351*0fca6ea1SDimitry Andric       if (!NewDbgFragment)
5352*0fca6ea1SDimitry Andric         NewDbgFragment = DbgVariable->getFragment();
5353*0fca6ea1SDimitry Andric 
5354*0fca6ea1SDimitry Andric       // Reduce the new expression offset by the bit-extract offset since
5355*0fca6ea1SDimitry Andric       // we'll be keeping that.
5356*0fca6ea1SDimitry Andric       int64_t OffestFromNewAllocaInBits =
5357*0fca6ea1SDimitry Andric           OffsetFromLocationInBits - ExtractOffsetInBits;
5358*0fca6ea1SDimitry Andric       // We need to adjust an existing bit extract if the offset expression
5359*0fca6ea1SDimitry Andric       // can't eat the slack (i.e., if the new offset would be negative).
5360*0fca6ea1SDimitry Andric       int64_t BitExtractOffset =
5361*0fca6ea1SDimitry Andric           std::min<int64_t>(0, OffestFromNewAllocaInBits);
5362*0fca6ea1SDimitry Andric       // The magnitude of a negative value indicates the number of bits into
5363*0fca6ea1SDimitry Andric       // the existing variable fragment that the memory region begins. The new
5364*0fca6ea1SDimitry Andric       // variable fragment already excludes those bits - the new DbgPtr offset
5365*0fca6ea1SDimitry Andric       // only needs to be applied if it's positive.
5366*0fca6ea1SDimitry Andric       OffestFromNewAllocaInBits =
5367*0fca6ea1SDimitry Andric           std::max(int64_t(0), OffestFromNewAllocaInBits);
5368*0fca6ea1SDimitry Andric 
5369*0fca6ea1SDimitry Andric       // Rebuild the expression:
5370*0fca6ea1SDimitry Andric       //    {Offset(OffestFromNewAllocaInBits), PostOffsetOps, NewDbgFragment}
5371*0fca6ea1SDimitry Andric       // Add NewDbgFragment later, because dbg.assigns don't want it in the
5372*0fca6ea1SDimitry Andric       // address expression but the value expression instead.
5373*0fca6ea1SDimitry Andric       DIExpression *NewExpr = DIExpression::get(AI.getContext(), PostOffsetOps);
5374*0fca6ea1SDimitry Andric       if (OffestFromNewAllocaInBits > 0) {
5375*0fca6ea1SDimitry Andric         int64_t OffsetInBytes = (OffestFromNewAllocaInBits + 7) / 8;
5376*0fca6ea1SDimitry Andric         NewExpr = DIExpression::prepend(NewExpr, /*flags=*/0, OffsetInBytes);
53770b57cec5SDimitry Andric       }
53780b57cec5SDimitry Andric 
5379e8d8bef9SDimitry Andric       // Remove any existing intrinsics on the new alloca describing
5380e8d8bef9SDimitry Andric       // the variable fragment.
53815f757f3fSDimitry Andric       auto RemoveOne = [DbgVariable](auto *OldDII) {
53825f757f3fSDimitry Andric         auto SameVariableFragment = [](const auto *LHS, const auto *RHS) {
5383e8d8bef9SDimitry Andric           return LHS->getVariable() == RHS->getVariable() &&
5384e8d8bef9SDimitry Andric                  LHS->getDebugLoc()->getInlinedAt() ==
5385e8d8bef9SDimitry Andric                      RHS->getDebugLoc()->getInlinedAt();
5386e8d8bef9SDimitry Andric         };
538706c3fb27SDimitry Andric         if (SameVariableFragment(OldDII, DbgVariable))
53880b57cec5SDimitry Andric           OldDII->eraseFromParent();
53895f757f3fSDimitry Andric       };
53907a6dacacSDimitry Andric       for_each(findDbgDeclares(Fragment.Alloca), RemoveOne);
5391*0fca6ea1SDimitry Andric       for_each(findDVRDeclares(Fragment.Alloca), RemoveOne);
53920b57cec5SDimitry Andric 
5393*0fca6ea1SDimitry Andric       insertNewDbgInst(DIB, DbgVariable, Fragment.Alloca, NewExpr, &AI,
5394*0fca6ea1SDimitry Andric                        NewDbgFragment, BitExtractOffset);
5395bdd1243dSDimitry Andric     }
53965f757f3fSDimitry Andric   };
53975f757f3fSDimitry Andric 
53985f757f3fSDimitry Andric   // Migrate debug information from the old alloca to the new alloca(s)
53995f757f3fSDimitry Andric   // and the individual partitions.
54007a6dacacSDimitry Andric   for_each(findDbgDeclares(&AI), MigrateOne);
5401*0fca6ea1SDimitry Andric   for_each(findDVRDeclares(&AI), MigrateOne);
54025f757f3fSDimitry Andric   for_each(at::getAssignmentMarkers(&AI), MigrateOne);
5403*0fca6ea1SDimitry Andric   for_each(at::getDVRAssignmentMarkers(&AI), MigrateOne);
54045f757f3fSDimitry Andric 
54050b57cec5SDimitry Andric   return Changed;
54060b57cec5SDimitry Andric }
54070b57cec5SDimitry Andric 
540804eeddc0SDimitry Andric /// Clobber a use with poison, deleting the used value if it becomes dead.
54095f757f3fSDimitry Andric void SROA::clobberUse(Use &U) {
54100b57cec5SDimitry Andric   Value *OldV = U;
541104eeddc0SDimitry Andric   // Replace the use with an poison value.
541204eeddc0SDimitry Andric   U = PoisonValue::get(OldV->getType());
54130b57cec5SDimitry Andric 
54140b57cec5SDimitry Andric   // Check for this making an instruction dead. We have to garbage collect
54150b57cec5SDimitry Andric   // all the dead instructions to ensure the uses of any alloca end up being
54160b57cec5SDimitry Andric   // minimal.
54170b57cec5SDimitry Andric   if (Instruction *OldI = dyn_cast<Instruction>(OldV))
54180b57cec5SDimitry Andric     if (isInstructionTriviallyDead(OldI)) {
5419e8d8bef9SDimitry Andric       DeadInsts.push_back(OldI);
54200b57cec5SDimitry Andric     }
54210b57cec5SDimitry Andric }
54220b57cec5SDimitry Andric 
54230b57cec5SDimitry Andric /// Analyze an alloca for SROA.
54240b57cec5SDimitry Andric ///
54250b57cec5SDimitry Andric /// This analyzes the alloca to ensure we can reason about it, builds
54260b57cec5SDimitry Andric /// the slices of the alloca, and then hands it off to be split and
54270b57cec5SDimitry Andric /// rewritten as needed.
5428bdd1243dSDimitry Andric std::pair<bool /*Changed*/, bool /*CFGChanged*/>
54295f757f3fSDimitry Andric SROA::runOnAlloca(AllocaInst &AI) {
5430bdd1243dSDimitry Andric   bool Changed = false;
5431bdd1243dSDimitry Andric   bool CFGChanged = false;
5432bdd1243dSDimitry Andric 
54330b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "SROA alloca: " << AI << "\n");
54340b57cec5SDimitry Andric   ++NumAllocasAnalyzed;
54350b57cec5SDimitry Andric 
54360b57cec5SDimitry Andric   // Special case dead allocas, as they're trivial.
54370b57cec5SDimitry Andric   if (AI.use_empty()) {
54380b57cec5SDimitry Andric     AI.eraseFromParent();
5439bdd1243dSDimitry Andric     Changed = true;
5440bdd1243dSDimitry Andric     return {Changed, CFGChanged};
54410b57cec5SDimitry Andric   }
5442*0fca6ea1SDimitry Andric   const DataLayout &DL = AI.getDataLayout();
54430b57cec5SDimitry Andric 
54440b57cec5SDimitry Andric   // Skip alloca forms that this analysis can't handle.
54455ffd83dbSDimitry Andric   auto *AT = AI.getAllocatedType();
544606c3fb27SDimitry Andric   TypeSize Size = DL.getTypeAllocSize(AT);
544706c3fb27SDimitry Andric   if (AI.isArrayAllocation() || !AT->isSized() || Size.isScalable() ||
544806c3fb27SDimitry Andric       Size.getFixedValue() == 0)
5449bdd1243dSDimitry Andric     return {Changed, CFGChanged};
54500b57cec5SDimitry Andric 
54510b57cec5SDimitry Andric   // First, split any FCA loads and stores touching this alloca to promote
54520b57cec5SDimitry Andric   // better splitting and promotion opportunities.
545304eeddc0SDimitry Andric   IRBuilderTy IRB(&AI);
545404eeddc0SDimitry Andric   AggLoadStoreRewriter AggRewriter(DL, IRB);
54550b57cec5SDimitry Andric   Changed |= AggRewriter.rewrite(AI);
54560b57cec5SDimitry Andric 
54570b57cec5SDimitry Andric   // Build the slices using a recursive instruction-visiting builder.
54580b57cec5SDimitry Andric   AllocaSlices AS(DL, AI);
54590b57cec5SDimitry Andric   LLVM_DEBUG(AS.print(dbgs()));
54600b57cec5SDimitry Andric   if (AS.isEscaped())
5461bdd1243dSDimitry Andric     return {Changed, CFGChanged};
54620b57cec5SDimitry Andric 
54630b57cec5SDimitry Andric   // Delete all the dead users of this alloca before splitting and rewriting it.
54640b57cec5SDimitry Andric   for (Instruction *DeadUser : AS.getDeadUsers()) {
54650b57cec5SDimitry Andric     // Free up everything used by this instruction.
54660b57cec5SDimitry Andric     for (Use &DeadOp : DeadUser->operands())
54670b57cec5SDimitry Andric       clobberUse(DeadOp);
54680b57cec5SDimitry Andric 
54690b57cec5SDimitry Andric     // Now replace the uses of this instruction.
547004eeddc0SDimitry Andric     DeadUser->replaceAllUsesWith(PoisonValue::get(DeadUser->getType()));
54710b57cec5SDimitry Andric 
54720b57cec5SDimitry Andric     // And mark it for deletion.
5473e8d8bef9SDimitry Andric     DeadInsts.push_back(DeadUser);
54740b57cec5SDimitry Andric     Changed = true;
54750b57cec5SDimitry Andric   }
54760b57cec5SDimitry Andric   for (Use *DeadOp : AS.getDeadOperands()) {
54770b57cec5SDimitry Andric     clobberUse(*DeadOp);
54780b57cec5SDimitry Andric     Changed = true;
54790b57cec5SDimitry Andric   }
54800b57cec5SDimitry Andric 
54810b57cec5SDimitry Andric   // No slices to split. Leave the dead alloca for a later pass to clean up.
54820b57cec5SDimitry Andric   if (AS.begin() == AS.end())
5483bdd1243dSDimitry Andric     return {Changed, CFGChanged};
54840b57cec5SDimitry Andric 
54850b57cec5SDimitry Andric   Changed |= splitAlloca(AI, AS);
54860b57cec5SDimitry Andric 
54870b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "  Speculating PHIs\n");
54880b57cec5SDimitry Andric   while (!SpeculatablePHIs.empty())
548904eeddc0SDimitry Andric     speculatePHINodeLoads(IRB, *SpeculatablePHIs.pop_back_val());
54900b57cec5SDimitry Andric 
5491bdd1243dSDimitry Andric   LLVM_DEBUG(dbgs() << "  Rewriting Selects\n");
5492bdd1243dSDimitry Andric   auto RemainingSelectsToRewrite = SelectsToRewrite.takeVector();
5493bdd1243dSDimitry Andric   while (!RemainingSelectsToRewrite.empty()) {
5494bdd1243dSDimitry Andric     const auto [K, V] = RemainingSelectsToRewrite.pop_back_val();
5495bdd1243dSDimitry Andric     CFGChanged |=
5496bdd1243dSDimitry Andric         rewriteSelectInstMemOps(*K, V, IRB, PreserveCFG ? nullptr : DTU);
5497bdd1243dSDimitry Andric   }
54980b57cec5SDimitry Andric 
5499bdd1243dSDimitry Andric   return {Changed, CFGChanged};
55000b57cec5SDimitry Andric }
55010b57cec5SDimitry Andric 
55020b57cec5SDimitry Andric /// Delete the dead instructions accumulated in this run.
55030b57cec5SDimitry Andric ///
55040b57cec5SDimitry Andric /// Recursively deletes the dead instructions we've accumulated. This is done
55050b57cec5SDimitry Andric /// at the very end to maximize locality of the recursive delete and to
55060b57cec5SDimitry Andric /// minimize the problems of invalidated instruction pointers as such pointers
55070b57cec5SDimitry Andric /// are used heavily in the intermediate stages of the algorithm.
55080b57cec5SDimitry Andric ///
55090b57cec5SDimitry Andric /// We also record the alloca instructions deleted here so that they aren't
55100b57cec5SDimitry Andric /// subsequently handed to mem2reg to promote.
55115f757f3fSDimitry Andric bool SROA::deleteDeadInstructions(
55120b57cec5SDimitry Andric     SmallPtrSetImpl<AllocaInst *> &DeletedAllocas) {
55130b57cec5SDimitry Andric   bool Changed = false;
55140b57cec5SDimitry Andric   while (!DeadInsts.empty()) {
5515e8d8bef9SDimitry Andric     Instruction *I = dyn_cast_or_null<Instruction>(DeadInsts.pop_back_val());
5516bdd1243dSDimitry Andric     if (!I)
5517bdd1243dSDimitry Andric       continue;
55180b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "Deleting dead instruction: " << *I << "\n");
55190b57cec5SDimitry Andric 
55200b57cec5SDimitry Andric     // If the instruction is an alloca, find the possible dbg.declare connected
55210b57cec5SDimitry Andric     // to it, and remove it too. We must do this before calling RAUW or we will
55220b57cec5SDimitry Andric     // not be able to find it.
55230b57cec5SDimitry Andric     if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
55240b57cec5SDimitry Andric       DeletedAllocas.insert(AI);
55257a6dacacSDimitry Andric       for (DbgDeclareInst *OldDII : findDbgDeclares(AI))
55265f757f3fSDimitry Andric         OldDII->eraseFromParent();
5527*0fca6ea1SDimitry Andric       for (DbgVariableRecord *OldDII : findDVRDeclares(AI))
55280b57cec5SDimitry Andric         OldDII->eraseFromParent();
55290b57cec5SDimitry Andric     }
55300b57cec5SDimitry Andric 
5531bdd1243dSDimitry Andric     at::deleteAssignmentMarkers(I);
55320b57cec5SDimitry Andric     I->replaceAllUsesWith(UndefValue::get(I->getType()));
55330b57cec5SDimitry Andric 
55340b57cec5SDimitry Andric     for (Use &Operand : I->operands())
55350b57cec5SDimitry Andric       if (Instruction *U = dyn_cast<Instruction>(Operand)) {
55360b57cec5SDimitry Andric         // Zero out the operand and see if it becomes trivially dead.
55370b57cec5SDimitry Andric         Operand = nullptr;
55380b57cec5SDimitry Andric         if (isInstructionTriviallyDead(U))
5539e8d8bef9SDimitry Andric           DeadInsts.push_back(U);
55400b57cec5SDimitry Andric       }
55410b57cec5SDimitry Andric 
55420b57cec5SDimitry Andric     ++NumDeleted;
55430b57cec5SDimitry Andric     I->eraseFromParent();
55440b57cec5SDimitry Andric     Changed = true;
55450b57cec5SDimitry Andric   }
55460b57cec5SDimitry Andric   return Changed;
55470b57cec5SDimitry Andric }
55480b57cec5SDimitry Andric 
55490b57cec5SDimitry Andric /// Promote the allocas, using the best available technique.
55500b57cec5SDimitry Andric ///
55510b57cec5SDimitry Andric /// This attempts to promote whatever allocas have been identified as viable in
55520b57cec5SDimitry Andric /// the PromotableAllocas list. If that list is empty, there is nothing to do.
55530b57cec5SDimitry Andric /// This function returns whether any promotion occurred.
55545f757f3fSDimitry Andric bool SROA::promoteAllocas(Function &F) {
55550b57cec5SDimitry Andric   if (PromotableAllocas.empty())
55560b57cec5SDimitry Andric     return false;
55570b57cec5SDimitry Andric 
55580b57cec5SDimitry Andric   NumPromoted += PromotableAllocas.size();
55590b57cec5SDimitry Andric 
556006c3fb27SDimitry Andric   if (SROASkipMem2Reg) {
556106c3fb27SDimitry Andric     LLVM_DEBUG(dbgs() << "Not promoting allocas with mem2reg!\n");
556206c3fb27SDimitry Andric   } else {
55630b57cec5SDimitry Andric     LLVM_DEBUG(dbgs() << "Promoting allocas with mem2reg...\n");
5564bdd1243dSDimitry Andric     PromoteMemToReg(PromotableAllocas, DTU->getDomTree(), AC);
556506c3fb27SDimitry Andric   }
556606c3fb27SDimitry Andric 
55670b57cec5SDimitry Andric   PromotableAllocas.clear();
55680b57cec5SDimitry Andric   return true;
55690b57cec5SDimitry Andric }
55700b57cec5SDimitry Andric 
55715f757f3fSDimitry Andric std::pair<bool /*Changed*/, bool /*CFGChanged*/> SROA::runSROA(Function &F) {
55720b57cec5SDimitry Andric   LLVM_DEBUG(dbgs() << "SROA function: " << F.getName() << "\n");
55730b57cec5SDimitry Andric 
5574*0fca6ea1SDimitry Andric   const DataLayout &DL = F.getDataLayout();
55750b57cec5SDimitry Andric   BasicBlock &EntryBB = F.getEntryBlock();
55760b57cec5SDimitry Andric   for (BasicBlock::iterator I = EntryBB.begin(), E = std::prev(EntryBB.end());
55770b57cec5SDimitry Andric        I != E; ++I) {
55785ffd83dbSDimitry Andric     if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
557906c3fb27SDimitry Andric       if (DL.getTypeAllocSize(AI->getAllocatedType()).isScalable() &&
558006c3fb27SDimitry Andric           isAllocaPromotable(AI))
55815ffd83dbSDimitry Andric         PromotableAllocas.push_back(AI);
558206c3fb27SDimitry Andric       else
55830b57cec5SDimitry Andric         Worklist.insert(AI);
55840b57cec5SDimitry Andric     }
55855ffd83dbSDimitry Andric   }
55860b57cec5SDimitry Andric 
55870b57cec5SDimitry Andric   bool Changed = false;
5588bdd1243dSDimitry Andric   bool CFGChanged = false;
55890b57cec5SDimitry Andric   // A set of deleted alloca instruction pointers which should be removed from
55900b57cec5SDimitry Andric   // the list of promotable allocas.
55910b57cec5SDimitry Andric   SmallPtrSet<AllocaInst *, 4> DeletedAllocas;
55920b57cec5SDimitry Andric 
55930b57cec5SDimitry Andric   do {
55940b57cec5SDimitry Andric     while (!Worklist.empty()) {
5595bdd1243dSDimitry Andric       auto [IterationChanged, IterationCFGChanged] =
5596bdd1243dSDimitry Andric           runOnAlloca(*Worklist.pop_back_val());
5597bdd1243dSDimitry Andric       Changed |= IterationChanged;
5598bdd1243dSDimitry Andric       CFGChanged |= IterationCFGChanged;
5599bdd1243dSDimitry Andric 
56000b57cec5SDimitry Andric       Changed |= deleteDeadInstructions(DeletedAllocas);
56010b57cec5SDimitry Andric 
56020b57cec5SDimitry Andric       // Remove the deleted allocas from various lists so that we don't try to
56030b57cec5SDimitry Andric       // continue processing them.
56040b57cec5SDimitry Andric       if (!DeletedAllocas.empty()) {
56050b57cec5SDimitry Andric         auto IsInSet = [&](AllocaInst *AI) { return DeletedAllocas.count(AI); };
56060b57cec5SDimitry Andric         Worklist.remove_if(IsInSet);
56070b57cec5SDimitry Andric         PostPromotionWorklist.remove_if(IsInSet);
5608e8d8bef9SDimitry Andric         llvm::erase_if(PromotableAllocas, IsInSet);
56090b57cec5SDimitry Andric         DeletedAllocas.clear();
56100b57cec5SDimitry Andric       }
56110b57cec5SDimitry Andric     }
56120b57cec5SDimitry Andric 
56130b57cec5SDimitry Andric     Changed |= promoteAllocas(F);
56140b57cec5SDimitry Andric 
56150b57cec5SDimitry Andric     Worklist = PostPromotionWorklist;
56160b57cec5SDimitry Andric     PostPromotionWorklist.clear();
56170b57cec5SDimitry Andric   } while (!Worklist.empty());
56180b57cec5SDimitry Andric 
5619bdd1243dSDimitry Andric   assert((!CFGChanged || Changed) && "Can not only modify the CFG.");
5620bdd1243dSDimitry Andric   assert((!CFGChanged || !PreserveCFG) &&
5621bdd1243dSDimitry Andric          "Should not have modified the CFG when told to preserve it.");
5622bdd1243dSDimitry Andric 
56235f757f3fSDimitry Andric   if (Changed && isAssignmentTrackingEnabled(*F.getParent())) {
56247a6dacacSDimitry Andric     for (auto &BB : F) {
562506c3fb27SDimitry Andric       RemoveRedundantDbgInstrs(&BB);
562606c3fb27SDimitry Andric     }
56277a6dacacSDimitry Andric   }
562806c3fb27SDimitry Andric 
56295f757f3fSDimitry Andric   return {Changed, CFGChanged};
56305f757f3fSDimitry Andric }
56315f757f3fSDimitry Andric 
56325f757f3fSDimitry Andric PreservedAnalyses SROAPass::run(Function &F, FunctionAnalysisManager &AM) {
56335f757f3fSDimitry Andric   DominatorTree &DT = AM.getResult<DominatorTreeAnalysis>(F);
56345f757f3fSDimitry Andric   AssumptionCache &AC = AM.getResult<AssumptionAnalysis>(F);
56355f757f3fSDimitry Andric   DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
56365f757f3fSDimitry Andric   auto [Changed, CFGChanged] =
56375f757f3fSDimitry Andric       SROA(&F.getContext(), &DTU, &AC, PreserveCFG).runSROA(F);
56385f757f3fSDimitry Andric   if (!Changed)
56395f757f3fSDimitry Andric     return PreservedAnalyses::all();
56400b57cec5SDimitry Andric   PreservedAnalyses PA;
5641bdd1243dSDimitry Andric   if (!CFGChanged)
56420b57cec5SDimitry Andric     PA.preserveSet<CFGAnalyses>();
5643bdd1243dSDimitry Andric   PA.preserve<DominatorTreeAnalysis>();
56440b57cec5SDimitry Andric   return PA;
56450b57cec5SDimitry Andric }
56460b57cec5SDimitry Andric 
5647bdd1243dSDimitry Andric void SROAPass::printPipeline(
5648bdd1243dSDimitry Andric     raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) {
5649bdd1243dSDimitry Andric   static_cast<PassInfoMixin<SROAPass> *>(this)->printPipeline(
5650bdd1243dSDimitry Andric       OS, MapClassName2PassName);
56515f757f3fSDimitry Andric   OS << (PreserveCFG == SROAOptions::PreserveCFG ? "<preserve-cfg>"
56525f757f3fSDimitry Andric                                                  : "<modify-cfg>");
5653bdd1243dSDimitry Andric }
5654bdd1243dSDimitry Andric 
56555f757f3fSDimitry Andric SROAPass::SROAPass(SROAOptions PreserveCFG) : PreserveCFG(PreserveCFG) {}
56565f757f3fSDimitry Andric 
56575f757f3fSDimitry Andric namespace {
5658bdd1243dSDimitry Andric 
56590b57cec5SDimitry Andric /// A legacy pass for the legacy pass manager that wraps the \c SROA pass.
56605f757f3fSDimitry Andric class SROALegacyPass : public FunctionPass {
56615f757f3fSDimitry Andric   SROAOptions PreserveCFG;
56620b57cec5SDimitry Andric 
56630b57cec5SDimitry Andric public:
56640b57cec5SDimitry Andric   static char ID;
56650b57cec5SDimitry Andric 
5666bdd1243dSDimitry Andric   SROALegacyPass(SROAOptions PreserveCFG = SROAOptions::PreserveCFG)
56675f757f3fSDimitry Andric       : FunctionPass(ID), PreserveCFG(PreserveCFG) {
56680b57cec5SDimitry Andric     initializeSROALegacyPassPass(*PassRegistry::getPassRegistry());
56690b57cec5SDimitry Andric   }
56700b57cec5SDimitry Andric 
56710b57cec5SDimitry Andric   bool runOnFunction(Function &F) override {
56720b57cec5SDimitry Andric     if (skipFunction(F))
56730b57cec5SDimitry Andric       return false;
56740b57cec5SDimitry Andric 
56755f757f3fSDimitry Andric     DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
56765f757f3fSDimitry Andric     AssumptionCache &AC =
56775f757f3fSDimitry Andric         getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
56785f757f3fSDimitry Andric     DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
56795f757f3fSDimitry Andric     auto [Changed, _] =
56805f757f3fSDimitry Andric         SROA(&F.getContext(), &DTU, &AC, PreserveCFG).runSROA(F);
56815f757f3fSDimitry Andric     return Changed;
56820b57cec5SDimitry Andric   }
56830b57cec5SDimitry Andric 
56840b57cec5SDimitry Andric   void getAnalysisUsage(AnalysisUsage &AU) const override {
56850b57cec5SDimitry Andric     AU.addRequired<AssumptionCacheTracker>();
56860b57cec5SDimitry Andric     AU.addRequired<DominatorTreeWrapperPass>();
56870b57cec5SDimitry Andric     AU.addPreserved<GlobalsAAWrapperPass>();
5688bdd1243dSDimitry Andric     AU.addPreserved<DominatorTreeWrapperPass>();
56890b57cec5SDimitry Andric   }
56900b57cec5SDimitry Andric 
56910b57cec5SDimitry Andric   StringRef getPassName() const override { return "SROA"; }
56920b57cec5SDimitry Andric };
56930b57cec5SDimitry Andric 
56945f757f3fSDimitry Andric } // end anonymous namespace
56955f757f3fSDimitry Andric 
56960b57cec5SDimitry Andric char SROALegacyPass::ID = 0;
56970b57cec5SDimitry Andric 
5698bdd1243dSDimitry Andric FunctionPass *llvm::createSROAPass(bool PreserveCFG) {
5699bdd1243dSDimitry Andric   return new SROALegacyPass(PreserveCFG ? SROAOptions::PreserveCFG
5700bdd1243dSDimitry Andric                                         : SROAOptions::ModifyCFG);
5701bdd1243dSDimitry Andric }
57020b57cec5SDimitry Andric 
57030b57cec5SDimitry Andric INITIALIZE_PASS_BEGIN(SROALegacyPass, "sroa",
57040b57cec5SDimitry Andric                       "Scalar Replacement Of Aggregates", false, false)
57050b57cec5SDimitry Andric INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
57060b57cec5SDimitry Andric INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
57070b57cec5SDimitry Andric INITIALIZE_PASS_END(SROALegacyPass, "sroa", "Scalar Replacement Of Aggregates",
57080b57cec5SDimitry Andric                     false, false)
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