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