//===- InstCombine.h - Main InstCombine pass definition ---------*- C++ -*-===//
//
// 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/Analysis/ValueTracking.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Operator.h"
#include "llvm/InstVisitor.h"
#include "llvm/Pass.h"
#include "llvm/Support/TargetFolder.h"
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
namespace llvm {
class CallSite;
class DataLayout;
class TargetLibraryInfo;
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<Instruction>(V)) {
if (BinaryOperator::isNeg(V) ||
BinaryOperator::isFNeg(V) ||
BinaryOperator::isNot(V))
return 3;
return 4;
}
if (isa<Argument>(V)) return 3;
return isa<Constant>(V) ? (isa<UndefValue>(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<true> {
InstCombineWorklist &Worklist;
public:
InstCombineIRInserter(InstCombineWorklist &WL) : Worklist(WL) {}
void InsertHelper(Instruction *I, const Twine &Name,
BasicBlock *BB, BasicBlock::iterator InsertPt) const {
IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
Worklist.Add(I);
}
};
/// InstCombiner - The -instcombine pass.
class LLVM_LIBRARY_VISIBILITY InstCombiner
: public FunctionPass,
public InstVisitor<InstCombiner, Instruction*> {
DataLayout *TD;
TargetLibraryInfo *TLI;
bool MadeIRChange;
LibCallSimplifier *Simplifier;
bool MinimizeSize;
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<true, TargetFolder, InstCombineIRInserter> BuilderTy;
BuilderTy *Builder;
static char ID; // Pass identification, replacement for typeid
InstCombiner() : FunctionPass(ID), TD(0), Builder(0) {
MinimizeSize = false;
initializeInstCombinerPass(*PassRegistry::getPassRegistry());
}
public:
virtual bool runOnFunction(Function &F);
bool DoOneIteration(Function &F, unsigned ItNum);
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
DataLayout *getDataLayout() const { return TD; }
TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
// 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, Type *Ty);
Instruction *visitSub(BinaryOperator &I);
Instruction *visitFSub(BinaryOperator &I);
Instruction *visitMul(BinaryOperator &I);
Value *foldFMulConst(Instruction *FMulOrDiv, ConstantFP *C,
Instruction *InsertBefore);
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 *FoldICmpShrCst(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 *visitAllocSite(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);
Instruction *visitLandingPadInst(LandingPadInst &LI);
// visitInstruction - Specify what to return for unhandled instructions...
Instruction *visitInstruction(Instruction &I) { return 0; }
private:
bool ShouldChangeType(Type *From, Type *To) const;
Value *dyn_castNegVal(Value *V) const;
Value *dyn_castFNegVal(Value *V, bool NoSignedZero=false) const;
Type *FindElementAtOffset(Type *Ty, int64_t Offset,
SmallVectorImpl<Value*> &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,
Type *Ty);
Instruction *visitCallSite(CallSite CS);
Instruction *tryOptimizeCall(CallInst *CI, const DataLayout *TD);
bool transformConstExprCastCall(CallSite CS);
Instruction *transformCallThroughTrampoline(CallSite CS,
IntrinsicInst *Tramp);
Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
bool DoXform = true);
Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS);
Value *EmitGEPOffset(User *GEP);
Instruction *scalarizePHI(ExtractElementInst &EI, PHINode *PN);
Value *EvaluateInDifferentElementOrder(Value *V, ArrayRef<int> Mask);
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;
}
// InsertNewInstWith - same as InsertNewInstBefore, but also sets the
// debug loc.
//
Instruction *InsertNewInstWith(Instruction *New, Instruction &Old) {
New->setDebugLoc(Old.getDebugLoc());
return InsertNewInstBefore(New, Old);
}
// 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());
DEBUG(errs() << "IC: Replacing " << I << "\n"
" with " << *V << '\n');
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<Instruction>(*i))
Worklist.Add(Op);
}
Worklist.Remove(&I);
I.eraseFromParent();
MadeIRChange = true;
return 0; // Don't do anything with FI
}
void ComputeMaskedBits(Value *V, APInt &KnownZero,
APInt &KnownOne, unsigned Depth = 0) const {
return llvm::ComputeMaskedBits(V, 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);
/// Helper routine of SimplifyDemandedUseBits. It tries to simplify demanded
/// bit for "r1 = shr x, c1; r2 = shl r1, c2" instruction sequence.
Value *SimplifyShrShlDemandedBits(Instruction *Lsr, Instruction *Sftl,
APInt DemandedMask, APInt &KnownZero,
APInt &KnownOne);
/// 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).
//
Instruction *FoldOpIntoPhi(Instruction &I);
// 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, Type *Ty, bool isSigned);
/// Descale - Return a value X such that Val = X * Scale, or null if none. If
/// the multiplication is known not to overflow then NoSignedWrap is set.
Value *Descale(Value *Val, APInt Scale, bool &NoSignedWrap);
};
} // end namespace llvm.
#endif