xref: /llvm-project/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp (revision 266ff98cba44b9e969e6894eaa30d4fe37647210) 
1 //===- VPlanAnalysis.cpp - Various Analyses working on VPlan ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "VPlanAnalysis.h"
10 #include "VPlan.h"
11 #include "VPlanCFG.h"
12 #include "VPlanDominatorTree.h"
13 #include "llvm/ADT/TypeSwitch.h"
14 #include "llvm/Analysis/ScalarEvolution.h"
15 #include "llvm/IR/Instruction.h"
16 #include "llvm/IR/PatternMatch.h"
17 #include "llvm/Support/GenericDomTreeConstruction.h"
18 
19 using namespace llvm;
20 
21 #define DEBUG_TYPE "vplan"
22 
23 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPBlendRecipe *R) {
24   Type *ResTy = inferScalarType(R->getIncomingValue(0));
25   for (unsigned I = 1, E = R->getNumIncomingValues(); I != E; ++I) {
26     VPValue *Inc = R->getIncomingValue(I);
27     assert(inferScalarType(Inc) == ResTy &&
28            "different types inferred for different incoming values");
29     CachedTypes[Inc] = ResTy;
30   }
31   return ResTy;
32 }
33 
34 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPInstruction *R) {
35   // Set the result type from the first operand, check if the types for all
36   // other operands match and cache them.
37   auto SetResultTyFromOp = [this, R]() {
38     Type *ResTy = inferScalarType(R->getOperand(0));
39     for (unsigned Op = 1; Op != R->getNumOperands(); ++Op) {
40       VPValue *OtherV = R->getOperand(Op);
41       assert(inferScalarType(OtherV) == ResTy &&
42              "different types inferred for different operands");
43       CachedTypes[OtherV] = ResTy;
44     }
45     return ResTy;
46   };
47 
48   unsigned Opcode = R->getOpcode();
49   if (Instruction::isBinaryOp(Opcode) || Instruction::isUnaryOp(Opcode))
50     return SetResultTyFromOp();
51 
52   switch (Opcode) {
53   case Instruction::Select: {
54     Type *ResTy = inferScalarType(R->getOperand(1));
55     VPValue *OtherV = R->getOperand(2);
56     assert(inferScalarType(OtherV) == ResTy &&
57            "different types inferred for different operands");
58     CachedTypes[OtherV] = ResTy;
59     return ResTy;
60   }
61   case Instruction::ICmp:
62   case VPInstruction::ActiveLaneMask:
63     return inferScalarType(R->getOperand(1));
64   case VPInstruction::ExplicitVectorLength:
65     return Type::getIntNTy(Ctx, 32);
66   case VPInstruction::FirstOrderRecurrenceSplice:
67   case VPInstruction::Not:
68     return SetResultTyFromOp();
69   case VPInstruction::ExtractFromEnd: {
70     Type *BaseTy = inferScalarType(R->getOperand(0));
71     if (auto *VecTy = dyn_cast<VectorType>(BaseTy))
72       return VecTy->getElementType();
73     return BaseTy;
74   }
75   case VPInstruction::LogicalAnd:
76     return IntegerType::get(Ctx, 1);
77   case VPInstruction::PtrAdd:
78     // Return the type based on the pointer argument (i.e. first operand).
79     return inferScalarType(R->getOperand(0));
80   case VPInstruction::BranchOnCond:
81   case VPInstruction::BranchOnCount:
82     return Type::getVoidTy(Ctx);
83   default:
84     break;
85   }
86   // Type inference not implemented for opcode.
87   LLVM_DEBUG({
88     dbgs() << "LV: Found unhandled opcode for: ";
89     R->getVPSingleValue()->dump();
90   });
91   llvm_unreachable("Unhandled opcode!");
92 }
93 
94 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPWidenRecipe *R) {
95   unsigned Opcode = R->getOpcode();
96   switch (Opcode) {
97   case Instruction::ICmp:
98   case Instruction::FCmp:
99     return IntegerType::get(Ctx, 1);
100   case Instruction::UDiv:
101   case Instruction::SDiv:
102   case Instruction::SRem:
103   case Instruction::URem:
104   case Instruction::Add:
105   case Instruction::FAdd:
106   case Instruction::Sub:
107   case Instruction::FSub:
108   case Instruction::Mul:
109   case Instruction::FMul:
110   case Instruction::FDiv:
111   case Instruction::FRem:
112   case Instruction::Shl:
113   case Instruction::LShr:
114   case Instruction::AShr:
115   case Instruction::And:
116   case Instruction::Or:
117   case Instruction::Xor: {
118     Type *ResTy = inferScalarType(R->getOperand(0));
119     assert(ResTy == inferScalarType(R->getOperand(1)) &&
120            "types for both operands must match for binary op");
121     CachedTypes[R->getOperand(1)] = ResTy;
122     return ResTy;
123   }
124   case Instruction::FNeg:
125   case Instruction::Freeze:
126     return inferScalarType(R->getOperand(0));
127   default:
128     break;
129   }
130 
131   // Type inference not implemented for opcode.
132   LLVM_DEBUG({
133     dbgs() << "LV: Found unhandled opcode for: ";
134     R->getVPSingleValue()->dump();
135   });
136   llvm_unreachable("Unhandled opcode!");
137 }
138 
139 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPWidenCallRecipe *R) {
140   auto &CI = *cast<CallInst>(R->getUnderlyingInstr());
141   return CI.getType();
142 }
143 
144 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPWidenMemoryRecipe *R) {
145   assert((isa<VPWidenLoadRecipe>(R) || isa<VPWidenLoadEVLRecipe>(R)) &&
146          "Store recipes should not define any values");
147   return cast<LoadInst>(&R->getIngredient())->getType();
148 }
149 
150 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPWidenSelectRecipe *R) {
151   Type *ResTy = inferScalarType(R->getOperand(1));
152   VPValue *OtherV = R->getOperand(2);
153   assert(inferScalarType(OtherV) == ResTy &&
154          "different types inferred for different operands");
155   CachedTypes[OtherV] = ResTy;
156   return ResTy;
157 }
158 
159 Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPReplicateRecipe *R) {
160   switch (R->getUnderlyingInstr()->getOpcode()) {
161   case Instruction::Call: {
162     unsigned CallIdx = R->getNumOperands() - (R->isPredicated() ? 2 : 1);
163     return cast<Function>(R->getOperand(CallIdx)->getLiveInIRValue())
164         ->getReturnType();
165   }
166   case Instruction::UDiv:
167   case Instruction::SDiv:
168   case Instruction::SRem:
169   case Instruction::URem:
170   case Instruction::Add:
171   case Instruction::FAdd:
172   case Instruction::Sub:
173   case Instruction::FSub:
174   case Instruction::Mul:
175   case Instruction::FMul:
176   case Instruction::FDiv:
177   case Instruction::FRem:
178   case Instruction::Shl:
179   case Instruction::LShr:
180   case Instruction::AShr:
181   case Instruction::And:
182   case Instruction::Or:
183   case Instruction::Xor: {
184     Type *ResTy = inferScalarType(R->getOperand(0));
185     assert(ResTy == inferScalarType(R->getOperand(1)) &&
186            "inferred types for operands of binary op don't match");
187     CachedTypes[R->getOperand(1)] = ResTy;
188     return ResTy;
189   }
190   case Instruction::Select: {
191     Type *ResTy = inferScalarType(R->getOperand(1));
192     assert(ResTy == inferScalarType(R->getOperand(2)) &&
193            "inferred types for operands of select op don't match");
194     CachedTypes[R->getOperand(2)] = ResTy;
195     return ResTy;
196   }
197   case Instruction::ICmp:
198   case Instruction::FCmp:
199     return IntegerType::get(Ctx, 1);
200   case Instruction::AddrSpaceCast:
201   case Instruction::Alloca:
202   case Instruction::BitCast:
203   case Instruction::Trunc:
204   case Instruction::SExt:
205   case Instruction::ZExt:
206   case Instruction::FPExt:
207   case Instruction::FPTrunc:
208   case Instruction::ExtractValue:
209   case Instruction::SIToFP:
210   case Instruction::UIToFP:
211   case Instruction::FPToSI:
212   case Instruction::FPToUI:
213   case Instruction::PtrToInt:
214   case Instruction::IntToPtr:
215     return R->getUnderlyingInstr()->getType();
216   case Instruction::Freeze:
217   case Instruction::FNeg:
218   case Instruction::GetElementPtr:
219     return inferScalarType(R->getOperand(0));
220   case Instruction::Load:
221     return cast<LoadInst>(R->getUnderlyingInstr())->getType();
222   case Instruction::Store:
223     // FIXME: VPReplicateRecipes with store opcodes still define a result
224     // VPValue, so we need to handle them here. Remove the code here once this
225     // is modeled accurately in VPlan.
226     return Type::getVoidTy(Ctx);
227   default:
228     break;
229   }
230   // Type inference not implemented for opcode.
231   LLVM_DEBUG({
232     dbgs() << "LV: Found unhandled opcode for: ";
233     R->getVPSingleValue()->dump();
234   });
235   llvm_unreachable("Unhandled opcode");
236 }
237 
238 Type *VPTypeAnalysis::inferScalarType(const VPValue *V) {
239   if (Type *CachedTy = CachedTypes.lookup(V))
240     return CachedTy;
241 
242   if (V->isLiveIn()) {
243     if (auto *IRValue = V->getLiveInIRValue())
244       return IRValue->getType();
245     // All VPValues without any underlying IR value (like the vector trip count
246     // or the backedge-taken count) have the same type as the canonical IV.
247     return CanonicalIVTy;
248   }
249 
250   Type *ResultTy =
251       TypeSwitch<const VPRecipeBase *, Type *>(V->getDefiningRecipe())
252           .Case<VPActiveLaneMaskPHIRecipe, VPCanonicalIVPHIRecipe,
253                 VPFirstOrderRecurrencePHIRecipe, VPReductionPHIRecipe,
254                 VPWidenPointerInductionRecipe, VPEVLBasedIVPHIRecipe>(
255               [this](const auto *R) {
256                 // Handle header phi recipes, except VPWidenIntOrFpInduction
257                 // which needs special handling due it being possibly truncated.
258                 // TODO: consider inferring/caching type of siblings, e.g.,
259                 // backedge value, here and in cases below.
260                 return inferScalarType(R->getStartValue());
261               })
262           .Case<VPWidenIntOrFpInductionRecipe, VPDerivedIVRecipe>(
263               [](const auto *R) { return R->getScalarType(); })
264           .Case<VPReductionRecipe, VPPredInstPHIRecipe, VPWidenPHIRecipe,
265                 VPScalarIVStepsRecipe, VPWidenGEPRecipe, VPVectorPointerRecipe,
266                 VPReverseVectorPointerRecipe, VPWidenCanonicalIVRecipe>(
267               [this](const VPRecipeBase *R) {
268                 return inferScalarType(R->getOperand(0));
269               })
270           .Case<VPBlendRecipe, VPInstruction, VPWidenRecipe, VPWidenEVLRecipe,
271                 VPReplicateRecipe, VPWidenCallRecipe, VPWidenMemoryRecipe,
272                 VPWidenSelectRecipe>(
273               [this](const auto *R) { return inferScalarTypeForRecipe(R); })
274           .Case<VPWidenIntrinsicRecipe>([](const VPWidenIntrinsicRecipe *R) {
275             return R->getResultType();
276           })
277           .Case<VPInterleaveRecipe>([V](const VPInterleaveRecipe *R) {
278             // TODO: Use info from interleave group.
279             return V->getUnderlyingValue()->getType();
280           })
281           .Case<VPWidenCastRecipe>(
282               [](const VPWidenCastRecipe *R) { return R->getResultType(); })
283           .Case<VPScalarCastRecipe>(
284               [](const VPScalarCastRecipe *R) { return R->getResultType(); })
285           .Case<VPExpandSCEVRecipe>([](const VPExpandSCEVRecipe *R) {
286             return R->getSCEV()->getType();
287           })
288           .Case<VPReductionRecipe>([this](const auto *R) {
289             return inferScalarType(R->getChainOp());
290           });
291 
292   assert(ResultTy && "could not infer type for the given VPValue");
293   CachedTypes[V] = ResultTy;
294   return ResultTy;
295 }
296 
297 void llvm::collectEphemeralRecipesForVPlan(
298     VPlan &Plan, DenseSet<VPRecipeBase *> &EphRecipes) {
299   // First, collect seed recipes which are operands of assumes.
300   SmallVector<VPRecipeBase *> Worklist;
301   for (VPBasicBlock *VPBB : VPBlockUtils::blocksOnly<VPBasicBlock>(
302            vp_depth_first_deep(Plan.getVectorLoopRegion()->getEntry()))) {
303     for (VPRecipeBase &R : *VPBB) {
304       auto *RepR = dyn_cast<VPReplicateRecipe>(&R);
305       if (!RepR || !match(RepR->getUnderlyingInstr(),
306                           PatternMatch::m_Intrinsic<Intrinsic::assume>()))
307         continue;
308       Worklist.push_back(RepR);
309       EphRecipes.insert(RepR);
310     }
311   }
312 
313   // Process operands of candidates in worklist and add them to the set of
314   // ephemeral recipes, if they don't have side-effects and are only used by
315   // other ephemeral recipes.
316   while (!Worklist.empty()) {
317     VPRecipeBase *Cur = Worklist.pop_back_val();
318     for (VPValue *Op : Cur->operands()) {
319       auto *OpR = Op->getDefiningRecipe();
320       if (!OpR || OpR->mayHaveSideEffects() || EphRecipes.contains(OpR))
321         continue;
322       if (any_of(Op->users(), [EphRecipes](VPUser *U) {
323             auto *UR = dyn_cast<VPRecipeBase>(U);
324             return !UR || !EphRecipes.contains(UR);
325           }))
326         continue;
327       EphRecipes.insert(OpR);
328       Worklist.push_back(OpR);
329     }
330   }
331 }
332 
333 template void DomTreeBuilder::Calculate<DominatorTreeBase<VPBlockBase, false>>(
334     DominatorTreeBase<VPBlockBase, false> &DT);
335 
336 bool VPDominatorTree::properlyDominates(const VPRecipeBase *A,
337                                         const VPRecipeBase *B) {
338   if (A == B)
339     return false;
340 
341   auto LocalComesBefore = [](const VPRecipeBase *A, const VPRecipeBase *B) {
342     for (auto &R : *A->getParent()) {
343       if (&R == A)
344         return true;
345       if (&R == B)
346         return false;
347     }
348     llvm_unreachable("recipe not found");
349   };
350   const VPBlockBase *ParentA = A->getParent();
351   const VPBlockBase *ParentB = B->getParent();
352   if (ParentA == ParentB)
353     return LocalComesBefore(A, B);
354 
355 #ifndef NDEBUG
356   auto GetReplicateRegion = [](VPRecipeBase *R) -> VPRegionBlock * {
357     auto *Region = dyn_cast_or_null<VPRegionBlock>(R->getParent()->getParent());
358     if (Region && Region->isReplicator()) {
359       assert(Region->getNumSuccessors() == 1 &&
360              Region->getNumPredecessors() == 1 && "Expected SESE region!");
361       assert(R->getParent()->size() == 1 &&
362              "A recipe in an original replicator region must be the only "
363              "recipe in its block");
364       return Region;
365     }
366     return nullptr;
367   };
368   assert(!GetReplicateRegion(const_cast<VPRecipeBase *>(A)) &&
369          "No replicate regions expected at this point");
370   assert(!GetReplicateRegion(const_cast<VPRecipeBase *>(B)) &&
371          "No replicate regions expected at this point");
372 #endif
373   return Base::properlyDominates(ParentA, ParentB);
374 }
375