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361 lines
15 KiB
C++
361 lines
15 KiB
C++
//===- InstCombine.h - Main InstCombine pass definition -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef INSTCOMBINE_INSTCOMBINE_H
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#define INSTCOMBINE_INSTCOMBINE_H
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#include "InstCombineWorklist.h"
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#include "llvm/Pass.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/Support/IRBuilder.h"
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#include "llvm/Support/InstVisitor.h"
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#include "llvm/Support/TargetFolder.h"
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namespace llvm {
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class CallSite;
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class TargetData;
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class DbgDeclareInst;
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class MemIntrinsic;
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class MemSetInst;
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/// SelectPatternFlavor - We can match a variety of different patterns for
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/// select operations.
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enum SelectPatternFlavor {
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SPF_UNKNOWN = 0,
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SPF_SMIN, SPF_UMIN,
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SPF_SMAX, SPF_UMAX
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//SPF_ABS - TODO.
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};
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/// getComplexity: Assign a complexity or rank value to LLVM Values...
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/// 0 -> undef, 1 -> Const, 2 -> Other, 3 -> Arg, 3 -> Unary, 4 -> OtherInst
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static inline unsigned getComplexity(Value *V) {
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if (isa<Instruction>(V)) {
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if (BinaryOperator::isNeg(V) ||
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BinaryOperator::isFNeg(V) ||
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BinaryOperator::isNot(V))
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return 3;
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return 4;
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}
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if (isa<Argument>(V)) return 3;
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return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
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}
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/// InstCombineIRInserter - This is an IRBuilder insertion helper that works
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/// just like the normal insertion helper, but also adds any new instructions
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/// to the instcombine worklist.
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class LLVM_LIBRARY_VISIBILITY InstCombineIRInserter
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: public IRBuilderDefaultInserter<true> {
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InstCombineWorklist &Worklist;
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public:
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InstCombineIRInserter(InstCombineWorklist &WL) : Worklist(WL) {}
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void InsertHelper(Instruction *I, const Twine &Name,
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BasicBlock *BB, BasicBlock::iterator InsertPt) const {
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IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
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Worklist.Add(I);
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}
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};
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/// InstCombiner - The -instcombine pass.
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class LLVM_LIBRARY_VISIBILITY InstCombiner
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: public FunctionPass,
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public InstVisitor<InstCombiner, Instruction*> {
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TargetData *TD;
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bool MustPreserveLCSSA;
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bool MadeIRChange;
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public:
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/// Worklist - All of the instructions that need to be simplified.
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InstCombineWorklist Worklist;
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/// Builder - This is an IRBuilder that automatically inserts new
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/// instructions into the worklist when they are created.
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typedef IRBuilder<true, TargetFolder, InstCombineIRInserter> BuilderTy;
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BuilderTy *Builder;
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static char ID; // Pass identification, replacement for typeid
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InstCombiner() : FunctionPass(ID), TD(0), Builder(0) {
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initializeInstCombinerPass(*PassRegistry::getPassRegistry());
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}
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public:
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virtual bool runOnFunction(Function &F);
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bool DoOneIteration(Function &F, unsigned ItNum);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const;
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TargetData *getTargetData() const { return TD; }
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// Visitation implementation - Implement instruction combining for different
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// instruction types. The semantics are as follows:
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// Return Value:
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// null - No change was made
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// I - Change was made, I is still valid, I may be dead though
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// otherwise - Change was made, replace I with returned instruction
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//
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Instruction *visitAdd(BinaryOperator &I);
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Instruction *visitFAdd(BinaryOperator &I);
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Value *OptimizePointerDifference(Value *LHS, Value *RHS, const Type *Ty);
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Instruction *visitSub(BinaryOperator &I);
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Instruction *visitFSub(BinaryOperator &I);
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Instruction *visitMul(BinaryOperator &I);
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Instruction *visitFMul(BinaryOperator &I);
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Instruction *visitURem(BinaryOperator &I);
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Instruction *visitSRem(BinaryOperator &I);
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Instruction *visitFRem(BinaryOperator &I);
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bool SimplifyDivRemOfSelect(BinaryOperator &I);
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Instruction *commonRemTransforms(BinaryOperator &I);
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Instruction *commonIRemTransforms(BinaryOperator &I);
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Instruction *commonDivTransforms(BinaryOperator &I);
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Instruction *commonIDivTransforms(BinaryOperator &I);
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Instruction *visitUDiv(BinaryOperator &I);
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Instruction *visitSDiv(BinaryOperator &I);
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Instruction *visitFDiv(BinaryOperator &I);
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Value *FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS);
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Value *FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
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Instruction *visitAnd(BinaryOperator &I);
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Value *FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS);
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Value *FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
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Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op,
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Value *A, Value *B, Value *C);
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Instruction *visitOr (BinaryOperator &I);
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Instruction *visitXor(BinaryOperator &I);
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Instruction *visitShl(BinaryOperator &I);
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Instruction *visitAShr(BinaryOperator &I);
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Instruction *visitLShr(BinaryOperator &I);
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Instruction *commonShiftTransforms(BinaryOperator &I);
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Instruction *FoldFCmp_IntToFP_Cst(FCmpInst &I, Instruction *LHSI,
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Constant *RHSC);
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Instruction *FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
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GlobalVariable *GV, CmpInst &ICI,
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ConstantInt *AndCst = 0);
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Instruction *visitFCmpInst(FCmpInst &I);
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Instruction *visitICmpInst(ICmpInst &I);
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Instruction *visitICmpInstWithCastAndCast(ICmpInst &ICI);
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Instruction *visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
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Instruction *LHS,
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ConstantInt *RHS);
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Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
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ConstantInt *DivRHS);
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Instruction *FoldICmpAddOpCst(ICmpInst &ICI, Value *X, ConstantInt *CI,
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ICmpInst::Predicate Pred, Value *TheAdd);
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Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
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ICmpInst::Predicate Cond, Instruction &I);
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Instruction *FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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BinaryOperator &I);
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Instruction *commonCastTransforms(CastInst &CI);
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Instruction *commonPointerCastTransforms(CastInst &CI);
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Instruction *visitTrunc(TruncInst &CI);
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Instruction *visitZExt(ZExtInst &CI);
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Instruction *visitSExt(SExtInst &CI);
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Instruction *visitFPTrunc(FPTruncInst &CI);
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Instruction *visitFPExt(CastInst &CI);
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Instruction *visitFPToUI(FPToUIInst &FI);
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Instruction *visitFPToSI(FPToSIInst &FI);
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Instruction *visitUIToFP(CastInst &CI);
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Instruction *visitSIToFP(CastInst &CI);
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Instruction *visitPtrToInt(PtrToIntInst &CI);
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Instruction *visitIntToPtr(IntToPtrInst &CI);
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Instruction *visitBitCast(BitCastInst &CI);
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Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI,
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Instruction *FI);
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Instruction *FoldSelectIntoOp(SelectInst &SI, Value*, Value*);
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Instruction *FoldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
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Value *A, Value *B, Instruction &Outer,
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SelectPatternFlavor SPF2, Value *C);
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Instruction *visitSelectInst(SelectInst &SI);
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Instruction *visitSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
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Instruction *visitCallInst(CallInst &CI);
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Instruction *visitInvokeInst(InvokeInst &II);
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Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
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Instruction *visitPHINode(PHINode &PN);
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Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
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Instruction *visitAllocaInst(AllocaInst &AI);
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Instruction *visitMalloc(Instruction &FI);
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Instruction *visitFree(CallInst &FI);
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Instruction *visitLoadInst(LoadInst &LI);
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Instruction *visitStoreInst(StoreInst &SI);
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Instruction *visitBranchInst(BranchInst &BI);
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Instruction *visitSwitchInst(SwitchInst &SI);
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Instruction *visitInsertElementInst(InsertElementInst &IE);
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Instruction *visitExtractElementInst(ExtractElementInst &EI);
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Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
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Instruction *visitExtractValueInst(ExtractValueInst &EV);
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// visitInstruction - Specify what to return for unhandled instructions...
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Instruction *visitInstruction(Instruction &I) { return 0; }
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private:
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bool ShouldChangeType(const Type *From, const Type *To) const;
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Value *dyn_castNegVal(Value *V) const;
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Value *dyn_castFNegVal(Value *V) const;
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const Type *FindElementAtOffset(const Type *Ty, int64_t Offset,
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SmallVectorImpl<Value*> &NewIndices);
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Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
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/// ShouldOptimizeCast - Return true if the cast from "V to Ty" actually
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/// results in any code being generated and is interesting to optimize out. If
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/// the cast can be eliminated by some other simple transformation, we prefer
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/// to do the simplification first.
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bool ShouldOptimizeCast(Instruction::CastOps opcode,const Value *V,
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const Type *Ty);
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Instruction *visitCallSite(CallSite CS);
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Instruction *tryOptimizeCall(CallInst *CI, const TargetData *TD);
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bool transformConstExprCastCall(CallSite CS);
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Instruction *transformCallThroughTrampoline(CallSite CS);
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Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
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bool DoXform = true);
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bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS);
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DbgDeclareInst *hasOneUsePlusDeclare(Value *V);
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Value *EmitGEPOffset(User *GEP);
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public:
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// InsertNewInstBefore - insert an instruction New before instruction Old
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// in the program. Add the new instruction to the worklist.
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//
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Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
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assert(New && New->getParent() == 0 &&
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"New instruction already inserted into a basic block!");
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BasicBlock *BB = Old.getParent();
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BB->getInstList().insert(&Old, New); // Insert inst
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Worklist.Add(New);
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return New;
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}
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// ReplaceInstUsesWith - This method is to be used when an instruction is
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// found to be dead, replacable with another preexisting expression. Here
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// we add all uses of I to the worklist, replace all uses of I with the new
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// value, then return I, so that the inst combiner will know that I was
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// modified.
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//
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Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) {
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Worklist.AddUsersToWorkList(I); // Add all modified instrs to worklist.
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// If we are replacing the instruction with itself, this must be in a
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// segment of unreachable code, so just clobber the instruction.
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if (&I == V)
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V = UndefValue::get(I.getType());
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I.replaceAllUsesWith(V);
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return &I;
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}
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// EraseInstFromFunction - When dealing with an instruction that has side
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// effects or produces a void value, we can't rely on DCE to delete the
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// instruction. Instead, visit methods should return the value returned by
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// this function.
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Instruction *EraseInstFromFunction(Instruction &I) {
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DEBUG(errs() << "IC: ERASE " << I << '\n');
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assert(I.use_empty() && "Cannot erase instruction that is used!");
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// Make sure that we reprocess all operands now that we reduced their
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// use counts.
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if (I.getNumOperands() < 8) {
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for (User::op_iterator i = I.op_begin(), e = I.op_end(); i != e; ++i)
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if (Instruction *Op = dyn_cast<Instruction>(*i))
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Worklist.Add(Op);
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}
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Worklist.Remove(&I);
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I.eraseFromParent();
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MadeIRChange = true;
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return 0; // Don't do anything with FI
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}
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void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
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APInt &KnownOne, unsigned Depth = 0) const {
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return llvm::ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD, Depth);
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}
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bool MaskedValueIsZero(Value *V, const APInt &Mask,
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unsigned Depth = 0) const {
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return llvm::MaskedValueIsZero(V, Mask, TD, Depth);
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}
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unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0) const {
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return llvm::ComputeNumSignBits(Op, TD, Depth);
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}
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private:
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/// SimplifyAssociativeOrCommutative - This performs a few simplifications for
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/// operators which are associative or commutative.
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bool SimplifyAssociativeOrCommutative(BinaryOperator &I);
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/// SimplifyByFactorizing - This tries to simplify binary operations which
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/// some other binary operation distributes over by factorizing out a common
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/// term (eg "(A*B)+(A*C)" -> "A*(B+C)"). Returns the simplified value, or
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/// null if no simplification was performed.
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Instruction *SimplifyByFactorizing(BinaryOperator &I);
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/// SimplifyDemandedUseBits - Attempts to replace V with a simpler value
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/// based on the demanded bits.
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Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
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APInt& KnownZero, APInt& KnownOne,
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unsigned Depth);
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bool SimplifyDemandedBits(Use &U, APInt DemandedMask,
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APInt& KnownZero, APInt& KnownOne,
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unsigned Depth=0);
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/// SimplifyDemandedInstructionBits - Inst is an integer instruction that
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/// SimplifyDemandedBits knows about. See if the instruction has any
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/// properties that allow us to simplify its operands.
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bool SimplifyDemandedInstructionBits(Instruction &Inst);
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Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
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APInt& UndefElts, unsigned Depth = 0);
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// FoldOpIntoPhi - Given a binary operator, cast instruction, or select
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// which has a PHI node as operand #0, see if we can fold the instruction
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// into the PHI (which is only possible if all operands to the PHI are
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// constants).
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//
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// If AllowAggressive is true, FoldOpIntoPhi will allow certain transforms
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// that would normally be unprofitable because they strongly encourage jump
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// threading.
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Instruction *FoldOpIntoPhi(Instruction &I, bool AllowAggressive = false);
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// FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
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// operator and they all are only used by the PHI, PHI together their
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// inputs, and do the operation once, to the result of the PHI.
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Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);
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Instruction *FoldPHIArgBinOpIntoPHI(PHINode &PN);
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Instruction *FoldPHIArgGEPIntoPHI(PHINode &PN);
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Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
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Instruction *OptAndOp(Instruction *Op, ConstantInt *OpRHS,
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ConstantInt *AndRHS, BinaryOperator &TheAnd);
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Value *FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask,
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bool isSub, Instruction &I);
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Value *InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
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bool isSigned, bool Inside);
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Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
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Instruction *MatchBSwap(BinaryOperator &I);
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bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
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Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
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Instruction *SimplifyMemSet(MemSetInst *MI);
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Value *EvaluateInDifferentType(Value *V, const Type *Ty, bool isSigned);
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unsigned GetOrEnforceKnownAlignment(Value *V,
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unsigned PrefAlign = 0);
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};
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} // end namespace llvm.
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#endif
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