1 //===- InstCombine.h - Main InstCombine pass definition ---------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINE_H
11 #define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINE_H
12
13 #include "InstCombineWorklist.h"
14 #include "llvm/Analysis/AssumptionCache.h"
15 #include "llvm/Analysis/TargetFolder.h"
16 #include "llvm/Analysis/ValueTracking.h"
17 #include "llvm/IR/Dominators.h"
18 #include "llvm/IR/IRBuilder.h"
19 #include "llvm/IR/InstVisitor.h"
20 #include "llvm/IR/IntrinsicInst.h"
21 #include "llvm/IR/Operator.h"
22 #include "llvm/IR/PatternMatch.h"
23 #include "llvm/Pass.h"
24 #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
25
26 #define DEBUG_TYPE "instcombine"
27
28 namespace llvm {
29 class CallSite;
30 class DataLayout;
31 class DominatorTree;
32 class TargetLibraryInfo;
33 class DbgDeclareInst;
34 class MemIntrinsic;
35 class MemSetInst;
36
37 /// SelectPatternFlavor - We can match a variety of different patterns for
38 /// select operations.
39 enum SelectPatternFlavor {
40 SPF_UNKNOWN = 0,
41 SPF_SMIN,
42 SPF_UMIN,
43 SPF_SMAX,
44 SPF_UMAX,
45 SPF_ABS,
46 SPF_NABS
47 };
48
49 /// getComplexity: Assign a complexity or rank value to LLVM Values...
50 /// 0 -> undef, 1 -> Const, 2 -> Other, 3 -> Arg, 3 -> Unary, 4 -> OtherInst
getComplexity(Value * V)51 static inline unsigned getComplexity(Value *V) {
52 if (isa<Instruction>(V)) {
53 if (BinaryOperator::isNeg(V) || BinaryOperator::isFNeg(V) ||
54 BinaryOperator::isNot(V))
55 return 3;
56 return 4;
57 }
58 if (isa<Argument>(V))
59 return 3;
60 return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
61 }
62
63 /// AddOne - Add one to a Constant
AddOne(Constant * C)64 static inline Constant *AddOne(Constant *C) {
65 return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
66 }
67 /// SubOne - Subtract one from a Constant
SubOne(Constant * C)68 static inline Constant *SubOne(Constant *C) {
69 return ConstantExpr::getSub(C, ConstantInt::get(C->getType(), 1));
70 }
71
72 /// InstCombineIRInserter - This is an IRBuilder insertion helper that works
73 /// just like the normal insertion helper, but also adds any new instructions
74 /// to the instcombine worklist.
75 class LLVM_LIBRARY_VISIBILITY InstCombineIRInserter
76 : public IRBuilderDefaultInserter<true> {
77 InstCombineWorklist &Worklist;
78 AssumptionCache *AC;
79
80 public:
InstCombineIRInserter(InstCombineWorklist & WL,AssumptionCache * AC)81 InstCombineIRInserter(InstCombineWorklist &WL, AssumptionCache *AC)
82 : Worklist(WL), AC(AC) {}
83
InsertHelper(Instruction * I,const Twine & Name,BasicBlock * BB,BasicBlock::iterator InsertPt)84 void InsertHelper(Instruction *I, const Twine &Name, BasicBlock *BB,
85 BasicBlock::iterator InsertPt) const {
86 IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
87 Worklist.Add(I);
88
89 using namespace llvm::PatternMatch;
90 if (match(I, m_Intrinsic<Intrinsic::assume>()))
91 AC->registerAssumption(cast<CallInst>(I));
92 }
93 };
94
95 /// InstCombiner - The -instcombine pass.
96 class LLVM_LIBRARY_VISIBILITY InstCombiner
97 : public FunctionPass,
98 public InstVisitor<InstCombiner, Instruction *> {
99 AssumptionCache *AC;
100 const DataLayout *DL;
101 TargetLibraryInfo *TLI;
102 DominatorTree *DT;
103 bool MadeIRChange;
104 LibCallSimplifier *Simplifier;
105 bool MinimizeSize;
106
107 public:
108 /// Worklist - All of the instructions that need to be simplified.
109 InstCombineWorklist Worklist;
110
111 /// Builder - This is an IRBuilder that automatically inserts new
112 /// instructions into the worklist when they are created.
113 typedef IRBuilder<true, TargetFolder, InstCombineIRInserter> BuilderTy;
114 BuilderTy *Builder;
115
116 static char ID; // Pass identification, replacement for typeid
InstCombiner()117 InstCombiner()
118 : FunctionPass(ID), DL(nullptr), DT(nullptr), Builder(nullptr) {
119 MinimizeSize = false;
120 initializeInstCombinerPass(*PassRegistry::getPassRegistry());
121 }
122
123 public:
124 bool runOnFunction(Function &F) override;
125
126 bool DoOneIteration(Function &F, unsigned ItNum);
127
128 void getAnalysisUsage(AnalysisUsage &AU) const override;
129
getAssumptionCache()130 AssumptionCache *getAssumptionCache() const { return AC; }
131
getDataLayout()132 const DataLayout *getDataLayout() const { return DL; }
133
getDominatorTree()134 DominatorTree *getDominatorTree() const { return DT; }
135
getTargetLibraryInfo()136 TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
137
138 // Visitation implementation - Implement instruction combining for different
139 // instruction types. The semantics are as follows:
140 // Return Value:
141 // null - No change was made
142 // I - Change was made, I is still valid, I may be dead though
143 // otherwise - Change was made, replace I with returned instruction
144 //
145 Instruction *visitAdd(BinaryOperator &I);
146 Instruction *visitFAdd(BinaryOperator &I);
147 Value *OptimizePointerDifference(Value *LHS, Value *RHS, Type *Ty);
148 Instruction *visitSub(BinaryOperator &I);
149 Instruction *visitFSub(BinaryOperator &I);
150 Instruction *visitMul(BinaryOperator &I);
151 Value *foldFMulConst(Instruction *FMulOrDiv, Constant *C,
152 Instruction *InsertBefore);
153 Instruction *visitFMul(BinaryOperator &I);
154 Instruction *visitURem(BinaryOperator &I);
155 Instruction *visitSRem(BinaryOperator &I);
156 Instruction *visitFRem(BinaryOperator &I);
157 bool SimplifyDivRemOfSelect(BinaryOperator &I);
158 Instruction *commonRemTransforms(BinaryOperator &I);
159 Instruction *commonIRemTransforms(BinaryOperator &I);
160 Instruction *commonDivTransforms(BinaryOperator &I);
161 Instruction *commonIDivTransforms(BinaryOperator &I);
162 Instruction *visitUDiv(BinaryOperator &I);
163 Instruction *visitSDiv(BinaryOperator &I);
164 Instruction *visitFDiv(BinaryOperator &I);
165 Value *simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1, bool Inverted);
166 Value *FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS);
167 Value *FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
168 Instruction *visitAnd(BinaryOperator &I);
169 Value *FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction *CxtI);
170 Value *FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
171 Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op, Value *A,
172 Value *B, Value *C);
173 Instruction *FoldXorWithConstants(BinaryOperator &I, Value *Op, Value *A,
174 Value *B, Value *C);
175 Instruction *visitOr(BinaryOperator &I);
176 Instruction *visitXor(BinaryOperator &I);
177 Instruction *visitShl(BinaryOperator &I);
178 Instruction *visitAShr(BinaryOperator &I);
179 Instruction *visitLShr(BinaryOperator &I);
180 Instruction *commonShiftTransforms(BinaryOperator &I);
181 Instruction *FoldFCmp_IntToFP_Cst(FCmpInst &I, Instruction *LHSI,
182 Constant *RHSC);
183 Instruction *FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
184 GlobalVariable *GV, CmpInst &ICI,
185 ConstantInt *AndCst = nullptr);
186 Instruction *visitFCmpInst(FCmpInst &I);
187 Instruction *visitICmpInst(ICmpInst &I);
188 Instruction *visitICmpInstWithCastAndCast(ICmpInst &ICI);
189 Instruction *visitICmpInstWithInstAndIntCst(ICmpInst &ICI, Instruction *LHS,
190 ConstantInt *RHS);
191 Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
192 ConstantInt *DivRHS);
193 Instruction *FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *DivI,
194 ConstantInt *DivRHS);
195 Instruction *FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
196 ConstantInt *CI1, ConstantInt *CI2);
197 Instruction *FoldICmpCstShlCst(ICmpInst &I, Value *Op, Value *A,
198 ConstantInt *CI1, ConstantInt *CI2);
199 Instruction *FoldICmpAddOpCst(Instruction &ICI, Value *X, ConstantInt *CI,
200 ICmpInst::Predicate Pred);
201 Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
202 ICmpInst::Predicate Cond, Instruction &I);
203 Instruction *FoldShiftByConstant(Value *Op0, Constant *Op1,
204 BinaryOperator &I);
205 Instruction *commonCastTransforms(CastInst &CI);
206 Instruction *commonPointerCastTransforms(CastInst &CI);
207 Instruction *visitTrunc(TruncInst &CI);
208 Instruction *visitZExt(ZExtInst &CI);
209 Instruction *visitSExt(SExtInst &CI);
210 Instruction *visitFPTrunc(FPTruncInst &CI);
211 Instruction *visitFPExt(CastInst &CI);
212 Instruction *visitFPToUI(FPToUIInst &FI);
213 Instruction *visitFPToSI(FPToSIInst &FI);
214 Instruction *visitUIToFP(CastInst &CI);
215 Instruction *visitSIToFP(CastInst &CI);
216 Instruction *visitPtrToInt(PtrToIntInst &CI);
217 Instruction *visitIntToPtr(IntToPtrInst &CI);
218 Instruction *visitBitCast(BitCastInst &CI);
219 Instruction *visitAddrSpaceCast(AddrSpaceCastInst &CI);
220 Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI, Instruction *FI);
221 Instruction *FoldSelectIntoOp(SelectInst &SI, Value *, Value *);
222 Instruction *FoldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
223 Value *A, Value *B, Instruction &Outer,
224 SelectPatternFlavor SPF2, Value *C);
225 Instruction *visitSelectInst(SelectInst &SI);
226 Instruction *visitSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
227 Instruction *visitCallInst(CallInst &CI);
228 Instruction *visitInvokeInst(InvokeInst &II);
229
230 Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
231 Instruction *visitPHINode(PHINode &PN);
232 Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
233 Instruction *visitAllocaInst(AllocaInst &AI);
234 Instruction *visitAllocSite(Instruction &FI);
235 Instruction *visitFree(CallInst &FI);
236 Instruction *visitLoadInst(LoadInst &LI);
237 Instruction *visitStoreInst(StoreInst &SI);
238 Instruction *visitBranchInst(BranchInst &BI);
239 Instruction *visitSwitchInst(SwitchInst &SI);
240 Instruction *visitReturnInst(ReturnInst &RI);
241 Instruction *visitInsertValueInst(InsertValueInst &IV);
242 Instruction *visitInsertElementInst(InsertElementInst &IE);
243 Instruction *visitExtractElementInst(ExtractElementInst &EI);
244 Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
245 Instruction *visitExtractValueInst(ExtractValueInst &EV);
246 Instruction *visitLandingPadInst(LandingPadInst &LI);
247
248 // visitInstruction - Specify what to return for unhandled instructions...
visitInstruction(Instruction & I)249 Instruction *visitInstruction(Instruction &I) { return nullptr; }
250
251 // True when DB dominates all uses of DI execpt UI.
252 // UI must be in the same block as DI.
253 // The routine checks that the DI parent and DB are different.
254 bool dominatesAllUses(const Instruction *DI, const Instruction *UI,
255 const BasicBlock *DB) const;
256
257 // Replace select with select operand SIOpd in SI-ICmp sequence when possible
258 bool replacedSelectWithOperand(SelectInst *SI, const ICmpInst *Icmp,
259 const unsigned SIOpd);
260
261 private:
262 bool ShouldChangeType(Type *From, Type *To) const;
263 Value *dyn_castNegVal(Value *V) const;
264 Value *dyn_castFNegVal(Value *V, bool NoSignedZero = false) const;
265 Type *FindElementAtOffset(Type *PtrTy, int64_t Offset,
266 SmallVectorImpl<Value *> &NewIndices);
267 Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
268
269 /// ShouldOptimizeCast - Return true if the cast from "V to Ty" actually
270 /// results in any code being generated and is interesting to optimize out. If
271 /// the cast can be eliminated by some other simple transformation, we prefer
272 /// to do the simplification first.
273 bool ShouldOptimizeCast(Instruction::CastOps opcode, const Value *V,
274 Type *Ty);
275
276 Instruction *visitCallSite(CallSite CS);
277 Instruction *tryOptimizeCall(CallInst *CI, const DataLayout *DL);
278 bool transformConstExprCastCall(CallSite CS);
279 Instruction *transformCallThroughTrampoline(CallSite CS,
280 IntrinsicInst *Tramp);
281 Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
282 bool DoXform = true);
283 Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
284 bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS, Instruction *CxtI);
285 bool WillNotOverflowSignedSub(Value *LHS, Value *RHS, Instruction *CxtI);
286 bool WillNotOverflowUnsignedSub(Value *LHS, Value *RHS, Instruction *CxtI);
287 bool WillNotOverflowSignedMul(Value *LHS, Value *RHS, Instruction *CxtI);
288 Value *EmitGEPOffset(User *GEP);
289 Instruction *scalarizePHI(ExtractElementInst &EI, PHINode *PN);
290 Value *EvaluateInDifferentElementOrder(Value *V, ArrayRef<int> Mask);
291
292 public:
293 // InsertNewInstBefore - insert an instruction New before instruction Old
294 // in the program. Add the new instruction to the worklist.
295 //
InsertNewInstBefore(Instruction * New,Instruction & Old)296 Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
297 assert(New && !New->getParent() &&
298 "New instruction already inserted into a basic block!");
299 BasicBlock *BB = Old.getParent();
300 BB->getInstList().insert(&Old, New); // Insert inst
301 Worklist.Add(New);
302 return New;
303 }
304
305 // InsertNewInstWith - same as InsertNewInstBefore, but also sets the
306 // debug loc.
307 //
InsertNewInstWith(Instruction * New,Instruction & Old)308 Instruction *InsertNewInstWith(Instruction *New, Instruction &Old) {
309 New->setDebugLoc(Old.getDebugLoc());
310 return InsertNewInstBefore(New, Old);
311 }
312
313 // ReplaceInstUsesWith - This method is to be used when an instruction is
314 // found to be dead, replacable with another preexisting expression. Here
315 // we add all uses of I to the worklist, replace all uses of I with the new
316 // value, then return I, so that the inst combiner will know that I was
317 // modified.
318 //
ReplaceInstUsesWith(Instruction & I,Value * V)319 Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) {
320 Worklist.AddUsersToWorkList(I); // Add all modified instrs to worklist.
321
322 // If we are replacing the instruction with itself, this must be in a
323 // segment of unreachable code, so just clobber the instruction.
324 if (&I == V)
325 V = UndefValue::get(I.getType());
326
327 DEBUG(dbgs() << "IC: Replacing " << I << "\n"
328 " with " << *V << '\n');
329
330 I.replaceAllUsesWith(V);
331 return &I;
332 }
333
334 /// Creates a result tuple for an overflow intrinsic \p II with a given
335 /// \p Result and a constant \p Overflow value. If \p ReUseName is true the
336 /// \p Result's name is taken from \p II.
337 Instruction *CreateOverflowTuple(IntrinsicInst *II, Value *Result,
338 bool Overflow, bool ReUseName = true) {
339 if (ReUseName)
340 Result->takeName(II);
341 Constant *V[] = { UndefValue::get(Result->getType()),
342 Overflow ? Builder->getTrue() : Builder->getFalse() };
343 StructType *ST = cast<StructType>(II->getType());
344 Constant *Struct = ConstantStruct::get(ST, V);
345 return InsertValueInst::Create(Struct, Result, 0);
346 }
347
348 // EraseInstFromFunction - When dealing with an instruction that has side
349 // effects or produces a void value, we can't rely on DCE to delete the
350 // instruction. Instead, visit methods should return the value returned by
351 // this function.
EraseInstFromFunction(Instruction & I)352 Instruction *EraseInstFromFunction(Instruction &I) {
353 DEBUG(dbgs() << "IC: ERASE " << I << '\n');
354
355 assert(I.use_empty() && "Cannot erase instruction that is used!");
356 // Make sure that we reprocess all operands now that we reduced their
357 // use counts.
358 if (I.getNumOperands() < 8) {
359 for (User::op_iterator i = I.op_begin(), e = I.op_end(); i != e; ++i)
360 if (Instruction *Op = dyn_cast<Instruction>(*i))
361 Worklist.Add(Op);
362 }
363 Worklist.Remove(&I);
364 I.eraseFromParent();
365 MadeIRChange = true;
366 return nullptr; // Don't do anything with FI
367 }
368
369 void computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
370 unsigned Depth = 0, Instruction *CxtI = nullptr) const {
371 return llvm::computeKnownBits(V, KnownZero, KnownOne, DL, Depth, AC, CxtI,
372 DT);
373 }
374
375 bool MaskedValueIsZero(Value *V, const APInt &Mask,
376 unsigned Depth = 0,
377 Instruction *CxtI = nullptr) const {
378 return llvm::MaskedValueIsZero(V, Mask, DL, Depth, AC, CxtI, DT);
379 }
380 unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0,
381 Instruction *CxtI = nullptr) const {
382 return llvm::ComputeNumSignBits(Op, DL, Depth, AC, CxtI, DT);
383 }
384 void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
385 unsigned Depth = 0, Instruction *CxtI = nullptr) const {
386 return llvm::ComputeSignBit(V, KnownZero, KnownOne, DL, Depth, AC, CxtI,
387 DT);
388 }
computeOverflowForUnsignedMul(Value * LHS,Value * RHS,const Instruction * CxtI)389 OverflowResult computeOverflowForUnsignedMul(Value *LHS, Value *RHS,
390 const Instruction *CxtI) {
391 return llvm::computeOverflowForUnsignedMul(LHS, RHS, DL, AC, CxtI, DT);
392 }
computeOverflowForUnsignedAdd(Value * LHS,Value * RHS,const Instruction * CxtI)393 OverflowResult computeOverflowForUnsignedAdd(Value *LHS, Value *RHS,
394 const Instruction *CxtI) {
395 return llvm::computeOverflowForUnsignedAdd(LHS, RHS, DL, AC, CxtI, DT);
396 }
397
398 private:
399 /// SimplifyAssociativeOrCommutative - This performs a few simplifications for
400 /// operators which are associative or commutative.
401 bool SimplifyAssociativeOrCommutative(BinaryOperator &I);
402
403 /// SimplifyUsingDistributiveLaws - This tries to simplify binary operations
404 /// which some other binary operation distributes over either by factorizing
405 /// out common terms (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this
406 /// results in simplifications (eg: "A & (B | C) -> (A&B) | (A&C)" if this is
407 /// a win). Returns the simplified value, or null if it didn't simplify.
408 Value *SimplifyUsingDistributiveLaws(BinaryOperator &I);
409
410 /// SimplifyDemandedUseBits - Attempts to replace V with a simpler value
411 /// based on the demanded bits.
412 Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask, APInt &KnownZero,
413 APInt &KnownOne, unsigned Depth,
414 Instruction *CxtI = nullptr);
415 bool SimplifyDemandedBits(Use &U, APInt DemandedMask, APInt &KnownZero,
416 APInt &KnownOne, unsigned Depth = 0);
417 /// Helper routine of SimplifyDemandedUseBits. It tries to simplify demanded
418 /// bit for "r1 = shr x, c1; r2 = shl r1, c2" instruction sequence.
419 Value *SimplifyShrShlDemandedBits(Instruction *Lsr, Instruction *Sftl,
420 APInt DemandedMask, APInt &KnownZero,
421 APInt &KnownOne);
422
423 /// SimplifyDemandedInstructionBits - Inst is an integer instruction that
424 /// SimplifyDemandedBits knows about. See if the instruction has any
425 /// properties that allow us to simplify its operands.
426 bool SimplifyDemandedInstructionBits(Instruction &Inst);
427
428 Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
429 APInt &UndefElts, unsigned Depth = 0);
430
431 Value *SimplifyVectorOp(BinaryOperator &Inst);
432 Value *SimplifyBSwap(BinaryOperator &Inst);
433
434 // FoldOpIntoPhi - Given a binary operator, cast instruction, or select
435 // which has a PHI node as operand #0, see if we can fold the instruction
436 // into the PHI (which is only possible if all operands to the PHI are
437 // constants).
438 //
439 Instruction *FoldOpIntoPhi(Instruction &I);
440
441 // FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
442 // operator and they all are only used by the PHI, PHI together their
443 // inputs, and do the operation once, to the result of the PHI.
444 Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);
445 Instruction *FoldPHIArgBinOpIntoPHI(PHINode &PN);
446 Instruction *FoldPHIArgGEPIntoPHI(PHINode &PN);
447 Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
448
449 Instruction *OptAndOp(Instruction *Op, ConstantInt *OpRHS,
450 ConstantInt *AndRHS, BinaryOperator &TheAnd);
451
452 Value *FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask,
453 bool isSub, Instruction &I);
454 Value *InsertRangeTest(Value *V, Constant *Lo, Constant *Hi, bool isSigned,
455 bool Inside);
456 Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
457 Instruction *MatchBSwap(BinaryOperator &I);
458 bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
459 Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
460 Instruction *SimplifyMemSet(MemSetInst *MI);
461
462 Value *EvaluateInDifferentType(Value *V, Type *Ty, bool isSigned);
463
464 /// Descale - Return a value X such that Val = X * Scale, or null if none. If
465 /// the multiplication is known not to overflow then NoSignedWrap is set.
466 Value *Descale(Value *Val, APInt Scale, bool &NoSignedWrap);
467 };
468
469 } // end namespace llvm.
470
471 #undef DEBUG_TYPE
472
473 #endif
474