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26c8dcc692
This allows us to keep passing reduced masks to SimplifyDemandedBits, but know about all the bits if SimplifyDemandedBits fails. This allows instcombine to simplify cases like the one in the included testcase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
375 lines
16 KiB
C++
375 lines
16 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/IntrinsicInst.h"
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#include "llvm/Operator.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 TargetLibraryInfo;
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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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TargetLibraryInfo *TLI;
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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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TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
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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, 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 *FoldICmpShrCst(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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Instruction *visitLandingPadInst(LandingPadInst &LI);
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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(Type *From, 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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Type *FindElementAtOffset(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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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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IntrinsicInst *Tramp);
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Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
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bool DoXform = true);
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Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
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bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS);
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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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// InsertNewInstWith - same as InsertNewInstBefore, but also sets the
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// debug loc.
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//
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Instruction *InsertNewInstWith(Instruction *New, Instruction &Old) {
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New->setDebugLoc(Old.getDebugLoc());
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return InsertNewInstBefore(New, Old);
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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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DEBUG(errs() << "IC: Replacing " << I << "\n"
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" with " << *V << '\n');
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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, APInt &KnownZero,
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APInt &KnownOne, unsigned Depth = 0) const {
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return llvm::ComputeMaskedBits(V, 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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/// SimplifyUsingDistributiveLaws - This tries to simplify binary operations
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/// which some other binary operation distributes over either by factorizing
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/// out common terms (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this
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/// results in simplifications (eg: "A & (B | C) -> (A&B) | (A&C)" if this is
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/// a win). Returns the simplified value, or null if it didn't simplify.
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Value *SimplifyUsingDistributiveLaws(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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Instruction *FoldOpIntoPhi(Instruction &I);
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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, Type *Ty, bool isSigned);
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};
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} // end namespace llvm.
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#endif
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