ConstantFolding.cpp [plain text]
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Operator.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/FEnv.h"
#include <cerrno>
#include <cmath>
using namespace llvm;
static Constant *FoldBitCast(Constant *C, const Type *DestTy,
const TargetData &TD) {
const VectorType *DestVTy = dyn_cast<VectorType>(DestTy);
if (DestVTy == 0)
return ConstantExpr::getBitCast(C, DestTy);
if (isa<ConstantFP>(C) || isa<ConstantInt>(C)) {
Constant *Ops = C; return FoldBitCast(ConstantVector::get(Ops), DestTy, TD);
}
ConstantVector *CV = dyn_cast<ConstantVector>(C);
if (CV == 0)
return ConstantExpr::getBitCast(C, DestTy);
unsigned NumDstElt = DestVTy->getNumElements();
unsigned NumSrcElt = CV->getNumOperands();
if (NumDstElt == NumSrcElt)
return ConstantExpr::getBitCast(C, DestTy);
const Type *SrcEltTy = CV->getType()->getElementType();
const Type *DstEltTy = DestVTy->getElementType();
if (DstEltTy->isFloatingPointTy()) {
unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits();
const Type *DestIVTy =
VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumDstElt);
C = FoldBitCast(C, DestIVTy, TD);
if (!C) return ConstantExpr::getBitCast(C, DestTy);
return ConstantExpr::getBitCast(C, DestTy);
}
if (SrcEltTy->isFloatingPointTy()) {
unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits();
const Type *SrcIVTy =
VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElt);
C = ConstantExpr::getBitCast(C, SrcIVTy);
CV = dyn_cast<ConstantVector>(C);
if (!CV) return C;
}
bool isLittleEndian = TD.isLittleEndian();
SmallVector<Constant*, 32> Result;
if (NumDstElt < NumSrcElt) {
Constant *Zero = Constant::getNullValue(DstEltTy);
unsigned Ratio = NumSrcElt/NumDstElt;
unsigned SrcBitSize = SrcEltTy->getPrimitiveSizeInBits();
unsigned SrcElt = 0;
for (unsigned i = 0; i != NumDstElt; ++i) {
Constant *Elt = Zero;
unsigned ShiftAmt = isLittleEndian ? 0 : SrcBitSize*(Ratio-1);
for (unsigned j = 0; j != Ratio; ++j) {
Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(SrcElt++));
if (!Src) return ConstantExpr::getBitCast(C, DestTy);
Src = ConstantExpr::getZExt(Src, Elt->getType());
Src = ConstantExpr::getShl(Src,
ConstantInt::get(Src->getType(), ShiftAmt));
ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize;
Elt = ConstantExpr::getOr(Elt, Src);
}
Result.push_back(Elt);
}
} else {
unsigned Ratio = NumDstElt/NumSrcElt;
unsigned DstBitSize = DstEltTy->getPrimitiveSizeInBits();
for (unsigned i = 0; i != NumSrcElt; ++i) {
Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(i));
if (!Src) return ConstantExpr::getBitCast(C, DestTy);
unsigned ShiftAmt = isLittleEndian ? 0 : DstBitSize*(Ratio-1);
for (unsigned j = 0; j != Ratio; ++j) {
Constant *Elt = ConstantExpr::getLShr(Src,
ConstantInt::get(Src->getType(), ShiftAmt));
ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize;
Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy));
}
}
}
return ConstantVector::get(Result);
}
static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
int64_t &Offset, const TargetData &TD) {
if ((GV = dyn_cast<GlobalValue>(C))) {
Offset = 0;
return true;
}
ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
if (!CE) return false;
if (CE->getOpcode() == Instruction::PtrToInt ||
CE->getOpcode() == Instruction::BitCast)
return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD);
if (CE->getOpcode() == Instruction::GetElementPtr) {
if (!cast<PointerType>(CE->getOperand(0)->getType())
->getElementType()->isSized())
return false;
if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD))
return false;
gep_type_iterator GTI = gep_type_begin(CE);
for (User::const_op_iterator i = CE->op_begin() + 1, e = CE->op_end();
i != e; ++i, ++GTI) {
ConstantInt *CI = dyn_cast<ConstantInt>(*i);
if (!CI) return false; if (CI->isZero()) continue;
if (const StructType *ST = dyn_cast<StructType>(*GTI)) {
Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue());
} else {
const SequentialType *SQT = cast<SequentialType>(*GTI);
Offset += TD.getTypeAllocSize(SQT->getElementType())*CI->getSExtValue();
}
}
return true;
}
return false;
}
static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset,
unsigned char *CurPtr, unsigned BytesLeft,
const TargetData &TD) {
assert(ByteOffset <= TD.getTypeAllocSize(C->getType()) &&
"Out of range access");
if (isa<ConstantAggregateZero>(C) || isa<UndefValue>(C))
return true;
if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
if (CI->getBitWidth() > 64 ||
(CI->getBitWidth() & 7) != 0)
return false;
uint64_t Val = CI->getZExtValue();
unsigned IntBytes = unsigned(CI->getBitWidth()/8);
for (unsigned i = 0; i != BytesLeft && ByteOffset != IntBytes; ++i) {
CurPtr[i] = (unsigned char)(Val >> (ByteOffset * 8));
++ByteOffset;
}
return true;
}
if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
if (CFP->getType()->isDoubleTy()) {
C = FoldBitCast(C, Type::getInt64Ty(C->getContext()), TD);
return ReadDataFromGlobal(C, ByteOffset, CurPtr, BytesLeft, TD);
}
if (CFP->getType()->isFloatTy()){
C = FoldBitCast(C, Type::getInt32Ty(C->getContext()), TD);
return ReadDataFromGlobal(C, ByteOffset, CurPtr, BytesLeft, TD);
}
return false;
}
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
const StructLayout *SL = TD.getStructLayout(CS->getType());
unsigned Index = SL->getElementContainingOffset(ByteOffset);
uint64_t CurEltOffset = SL->getElementOffset(Index);
ByteOffset -= CurEltOffset;
while (1) {
uint64_t EltSize = TD.getTypeAllocSize(CS->getOperand(Index)->getType());
if (ByteOffset < EltSize &&
!ReadDataFromGlobal(CS->getOperand(Index), ByteOffset, CurPtr,
BytesLeft, TD))
return false;
++Index;
if (Index == CS->getType()->getNumElements())
return true;
uint64_t NextEltOffset = SL->getElementOffset(Index);
if (BytesLeft <= NextEltOffset-CurEltOffset-ByteOffset)
return true;
CurPtr += NextEltOffset-CurEltOffset-ByteOffset;
BytesLeft -= NextEltOffset-CurEltOffset-ByteOffset;
ByteOffset = 0;
CurEltOffset = NextEltOffset;
}
}
if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
uint64_t EltSize = TD.getTypeAllocSize(CA->getType()->getElementType());
uint64_t Index = ByteOffset / EltSize;
uint64_t Offset = ByteOffset - Index * EltSize;
for (; Index != CA->getType()->getNumElements(); ++Index) {
if (!ReadDataFromGlobal(CA->getOperand(Index), Offset, CurPtr,
BytesLeft, TD))
return false;
if (EltSize >= BytesLeft)
return true;
Offset = 0;
BytesLeft -= EltSize;
CurPtr += EltSize;
}
return true;
}
if (ConstantVector *CV = dyn_cast<ConstantVector>(C)) {
uint64_t EltSize = TD.getTypeAllocSize(CV->getType()->getElementType());
uint64_t Index = ByteOffset / EltSize;
uint64_t Offset = ByteOffset - Index * EltSize;
for (; Index != CV->getType()->getNumElements(); ++Index) {
if (!ReadDataFromGlobal(CV->getOperand(Index), Offset, CurPtr,
BytesLeft, TD))
return false;
if (EltSize >= BytesLeft)
return true;
Offset = 0;
BytesLeft -= EltSize;
CurPtr += EltSize;
}
return true;
}
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
if (CE->getOpcode() == Instruction::IntToPtr &&
CE->getOperand(0)->getType() == TD.getIntPtrType(CE->getContext()))
return ReadDataFromGlobal(CE->getOperand(0), ByteOffset, CurPtr,
BytesLeft, TD);
}
return false;
}
static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
const TargetData &TD) {
const Type *LoadTy = cast<PointerType>(C->getType())->getElementType();
const IntegerType *IntType = dyn_cast<IntegerType>(LoadTy);
if (!IntType) {
const Type *MapTy;
if (LoadTy->isFloatTy())
MapTy = Type::getInt32PtrTy(C->getContext());
else if (LoadTy->isDoubleTy())
MapTy = Type::getInt64PtrTy(C->getContext());
else if (LoadTy->isVectorTy()) {
MapTy = IntegerType::get(C->getContext(),
TD.getTypeAllocSizeInBits(LoadTy));
MapTy = PointerType::getUnqual(MapTy);
} else
return 0;
C = FoldBitCast(C, MapTy, TD);
if (Constant *Res = FoldReinterpretLoadFromConstPtr(C, TD))
return FoldBitCast(Res, LoadTy, TD);
return 0;
}
unsigned BytesLoaded = (IntType->getBitWidth() + 7) / 8;
if (BytesLoaded > 32 || BytesLoaded == 0) return 0;
GlobalValue *GVal;
int64_t Offset;
if (!IsConstantOffsetFromGlobal(C, GVal, Offset, TD))
return 0;
GlobalVariable *GV = dyn_cast<GlobalVariable>(GVal);
if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() ||
!GV->getInitializer()->getType()->isSized())
return 0;
if (Offset < 0) return 0;
if (uint64_t(Offset) >= TD.getTypeAllocSize(GV->getInitializer()->getType()))
return UndefValue::get(IntType);
unsigned char RawBytes[32] = {0};
if (!ReadDataFromGlobal(GV->getInitializer(), Offset, RawBytes,
BytesLoaded, TD))
return 0;
APInt ResultVal = APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1]);
for (unsigned i = 1; i != BytesLoaded; ++i) {
ResultVal <<= 8;
ResultVal |= RawBytes[BytesLoaded-1-i];
}
return ConstantInt::get(IntType->getContext(), ResultVal);
}
Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C,
const TargetData *TD) {
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
if (GV->isConstant() && GV->hasDefinitiveInitializer())
return GV->getInitializer();
ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
if (!CE) return 0;
if (CE->getOpcode() == Instruction::GetElementPtr) {
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0)))
if (GV->isConstant() && GV->hasDefinitiveInitializer())
if (Constant *V =
ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE))
return V;
}
std::string Str;
if (TD && GetConstantStringInfo(CE, Str) && !Str.empty()) {
unsigned StrLen = Str.length();
const Type *Ty = cast<PointerType>(CE->getType())->getElementType();
unsigned NumBits = Ty->getPrimitiveSizeInBits();
if ((NumBits >> 3) == StrLen + 1 && (NumBits & 7) == 0 &&
(isa<IntegerType>(Ty) || Ty->isFloatingPointTy())) {
APInt StrVal(NumBits, 0);
APInt SingleChar(NumBits, 0);
if (TD->isLittleEndian()) {
for (signed i = StrLen-1; i >= 0; i--) {
SingleChar = (uint64_t) Str[i] & UCHAR_MAX;
StrVal = (StrVal << 8) | SingleChar;
}
} else {
for (unsigned i = 0; i < StrLen; i++) {
SingleChar = (uint64_t) Str[i] & UCHAR_MAX;
StrVal = (StrVal << 8) | SingleChar;
}
SingleChar = 0;
StrVal = (StrVal << 8) | SingleChar;
}
Constant *Res = ConstantInt::get(CE->getContext(), StrVal);
if (Ty->isFloatingPointTy())
Res = ConstantExpr::getBitCast(Res, Ty);
return Res;
}
}
if (GlobalVariable *GV =
dyn_cast<GlobalVariable>(GetUnderlyingObject(CE, TD))) {
if (GV->isConstant() && GV->hasDefinitiveInitializer()) {
const Type *ResTy = cast<PointerType>(C->getType())->getElementType();
if (GV->getInitializer()->isNullValue())
return Constant::getNullValue(ResTy);
if (isa<UndefValue>(GV->getInitializer()))
return UndefValue::get(ResTy);
}
}
if (TD && TD->isLittleEndian())
return FoldReinterpretLoadFromConstPtr(CE, *TD);
return 0;
}
static Constant *ConstantFoldLoadInst(const LoadInst *LI, const TargetData *TD){
if (LI->isVolatile()) return 0;
if (Constant *C = dyn_cast<Constant>(LI->getOperand(0)))
return ConstantFoldLoadFromConstPtr(C, TD);
return 0;
}
static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
Constant *Op1, const TargetData *TD){
if (Opc == Instruction::Sub && TD) {
GlobalValue *GV1, *GV2;
int64_t Offs1, Offs2;
if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD))
if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) &&
GV1 == GV2) {
return ConstantInt::get(Op0->getType(), Offs1-Offs2);
}
}
return 0;
}
static Constant *CastGEPIndices(Constant *const *Ops, unsigned NumOps,
const Type *ResultTy,
const TargetData *TD) {
if (!TD) return 0;
const Type *IntPtrTy = TD->getIntPtrType(ResultTy->getContext());
bool Any = false;
SmallVector<Constant*, 32> NewIdxs;
for (unsigned i = 1; i != NumOps; ++i) {
if ((i == 1 ||
!isa<StructType>(GetElementPtrInst::getIndexedType(Ops[0]->getType(),
reinterpret_cast<Value *const *>(Ops+1),
i-1))) &&
Ops[i]->getType() != IntPtrTy) {
Any = true;
NewIdxs.push_back(ConstantExpr::getCast(CastInst::getCastOpcode(Ops[i],
true,
IntPtrTy,
true),
Ops[i], IntPtrTy));
} else
NewIdxs.push_back(Ops[i]);
}
if (!Any) return 0;
Constant *C =
ConstantExpr::getGetElementPtr(Ops[0], &NewIdxs[0], NewIdxs.size());
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
C = Folded;
return C;
}
static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps,
const Type *ResultTy,
const TargetData *TD) {
Constant *Ptr = Ops[0];
if (!TD || !cast<PointerType>(Ptr->getType())->getElementType()->isSized())
return 0;
const Type *IntPtrTy = TD->getIntPtrType(Ptr->getContext());
for (unsigned i = 1; i != NumOps; ++i)
if (!isa<ConstantInt>(Ops[i])) {
if (NumOps == 2 &&
cast<PointerType>(ResultTy)->getElementType()->isIntegerTy(8)) {
ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[1]);
assert((CE == 0 || CE->getType() == IntPtrTy) &&
"CastGEPIndices didn't canonicalize index types!");
if (CE && CE->getOpcode() == Instruction::Sub &&
CE->getOperand(0)->isNullValue()) {
Constant *Res = ConstantExpr::getPtrToInt(Ptr, CE->getType());
Res = ConstantExpr::getSub(Res, CE->getOperand(1));
Res = ConstantExpr::getIntToPtr(Res, ResultTy);
if (ConstantExpr *ResCE = dyn_cast<ConstantExpr>(Res))
Res = ConstantFoldConstantExpression(ResCE, TD);
return Res;
}
}
return 0;
}
unsigned BitWidth = TD->getTypeSizeInBits(IntPtrTy);
APInt Offset = APInt(BitWidth,
TD->getIndexedOffset(Ptr->getType(),
(Value**)Ops+1, NumOps-1));
Ptr = cast<Constant>(Ptr->stripPointerCasts());
while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
SmallVector<Value *, 4> NestedOps(GEP->op_begin()+1, GEP->op_end());
bool AllConstantInt = true;
for (unsigned i = 0, e = NestedOps.size(); i != e; ++i)
if (!isa<ConstantInt>(NestedOps[i])) {
AllConstantInt = false;
break;
}
if (!AllConstantInt)
break;
Ptr = cast<Constant>(GEP->getOperand(0));
Offset += APInt(BitWidth,
TD->getIndexedOffset(Ptr->getType(),
(Value**)NestedOps.data(),
NestedOps.size()));
Ptr = cast<Constant>(Ptr->stripPointerCasts());
}
APInt BasePtr(BitWidth, 0);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
if (CE->getOpcode() == Instruction::IntToPtr)
if (ConstantInt *Base = dyn_cast<ConstantInt>(CE->getOperand(0)))
BasePtr = Base->getValue().zextOrTrunc(BitWidth);
if (Ptr->isNullValue() || BasePtr != 0) {
Constant *C = ConstantInt::get(Ptr->getContext(), Offset+BasePtr);
return ConstantExpr::getIntToPtr(C, ResultTy);
}
const Type *Ty = Ptr->getType();
SmallVector<Constant*, 32> NewIdxs;
do {
if (const SequentialType *ATy = dyn_cast<SequentialType>(Ty)) {
if (ATy->isPointerTy()) {
if (!NewIdxs.empty())
break;
if (!ATy->getElementType()->isSized())
return 0;
}
APInt ElemSize(BitWidth, TD->getTypeAllocSize(ATy->getElementType()));
const IntegerType *IntPtrTy = TD->getIntPtrType(Ty->getContext());
if (ElemSize == 0)
NewIdxs.push_back(ConstantInt::get(IntPtrTy, 0));
else {
APInt NewIdx = Offset.udiv(ElemSize);
Offset -= NewIdx * ElemSize;
NewIdxs.push_back(ConstantInt::get(IntPtrTy, NewIdx));
}
Ty = ATy->getElementType();
} else if (const StructType *STy = dyn_cast<StructType>(Ty)) {
const StructLayout &SL = *TD->getStructLayout(STy);
unsigned ElIdx = SL.getElementContainingOffset(Offset.getZExtValue());
NewIdxs.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
ElIdx));
Offset -= APInt(BitWidth, SL.getElementOffset(ElIdx));
Ty = STy->getTypeAtIndex(ElIdx);
} else {
break;
}
} while (Ty != cast<PointerType>(ResultTy)->getElementType());
if (Offset != 0)
return 0;
Constant *C =
ConstantExpr::getGetElementPtr(Ptr, &NewIdxs[0], NewIdxs.size());
assert(cast<PointerType>(C->getType())->getElementType() == Ty &&
"Computed GetElementPtr has unexpected type!");
if (Ty != cast<PointerType>(ResultTy)->getElementType())
C = FoldBitCast(C, ResultTy, *TD);
return C;
}
Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) {
if (PHINode *PN = dyn_cast<PHINode>(I)) {
Constant *CommonValue = 0;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *Incoming = PN->getIncomingValue(i);
if (isa<UndefValue>(Incoming))
continue;
Constant *C = dyn_cast<Constant>(Incoming);
if (!C || (CommonValue && C != CommonValue))
return 0;
CommonValue = C;
}
return CommonValue ? CommonValue : UndefValue::get(PN->getType());
}
SmallVector<Constant*, 8> Ops;
for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i)
if (Constant *Op = dyn_cast<Constant>(*i))
Ops.push_back(Op);
else
return 0;
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1],
TD);
if (const LoadInst *LI = dyn_cast<LoadInst>(I))
return ConstantFoldLoadInst(LI, TD);
if (InsertValueInst *IVI = dyn_cast<InsertValueInst>(I))
return ConstantExpr::getInsertValue(
cast<Constant>(IVI->getAggregateOperand()),
cast<Constant>(IVI->getInsertedValueOperand()),
IVI->idx_begin(), IVI->getNumIndices());
if (ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I))
return ConstantExpr::getExtractValue(
cast<Constant>(EVI->getAggregateOperand()),
EVI->idx_begin(), EVI->getNumIndices());
return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
Ops.data(), Ops.size(), TD);
}
Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE,
const TargetData *TD) {
SmallVector<Constant*, 8> Ops;
for (User::const_op_iterator i = CE->op_begin(), e = CE->op_end();
i != e; ++i) {
Constant *NewC = cast<Constant>(*i);
if (ConstantExpr *NewCE = dyn_cast<ConstantExpr>(NewC))
NewC = ConstantFoldConstantExpression(NewCE, TD);
Ops.push_back(NewC);
}
if (CE->isCompare())
return ConstantFoldCompareInstOperands(CE->getPredicate(), Ops[0], Ops[1],
TD);
return ConstantFoldInstOperands(CE->getOpcode(), CE->getType(),
Ops.data(), Ops.size(), TD);
}
Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
Constant* const* Ops, unsigned NumOps,
const TargetData *TD) {
if (Instruction::isBinaryOp(Opcode)) {
if (isa<ConstantExpr>(Ops[0]) || isa<ConstantExpr>(Ops[1]))
if (Constant *C = SymbolicallyEvaluateBinop(Opcode, Ops[0], Ops[1], TD))
return C;
return ConstantExpr::get(Opcode, Ops[0], Ops[1]);
}
switch (Opcode) {
default: return 0;
case Instruction::ICmp:
case Instruction::FCmp: assert(0 && "Invalid for compares");
case Instruction::Call:
if (Function *F = dyn_cast<Function>(Ops[NumOps - 1]))
if (canConstantFoldCallTo(F))
return ConstantFoldCall(F, Ops, NumOps - 1);
return 0;
case Instruction::PtrToInt:
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) {
if (TD && CE->getOpcode() == Instruction::IntToPtr) {
Constant *Input = CE->getOperand(0);
unsigned InWidth = Input->getType()->getScalarSizeInBits();
if (TD->getPointerSizeInBits() < InWidth) {
Constant *Mask =
ConstantInt::get(CE->getContext(), APInt::getLowBitsSet(InWidth,
TD->getPointerSizeInBits()));
Input = ConstantExpr::getAnd(Input, Mask);
}
return ConstantExpr::getIntegerCast(Input, DestTy, false);
}
}
return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::IntToPtr:
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
if (TD &&
TD->getPointerSizeInBits() <= CE->getType()->getScalarSizeInBits() &&
CE->getOpcode() == Instruction::PtrToInt)
return FoldBitCast(CE->getOperand(0), DestTy, *TD);
return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPToUI:
case Instruction::FPToSI:
return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::BitCast:
if (TD)
return FoldBitCast(Ops[0], DestTy, *TD);
return ConstantExpr::getBitCast(Ops[0], DestTy);
case Instruction::Select:
return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
case Instruction::ExtractElement:
return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
case Instruction::InsertElement:
return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
case Instruction::ShuffleVector:
return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
case Instruction::GetElementPtr:
if (Constant *C = CastGEPIndices(Ops, NumOps, DestTy, TD))
return C;
if (Constant *C = SymbolicallyEvaluateGEP(Ops, NumOps, DestTy, TD))
return C;
return ConstantExpr::getGetElementPtr(Ops[0], Ops+1, NumOps-1);
}
}
Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate,
Constant *Ops0, Constant *Ops1,
const TargetData *TD) {
if (ConstantExpr *CE0 = dyn_cast<ConstantExpr>(Ops0)) {
if (TD && Ops1->isNullValue()) {
const Type *IntPtrTy = TD->getIntPtrType(CE0->getContext());
if (CE0->getOpcode() == Instruction::IntToPtr) {
Constant *C = ConstantExpr::getIntegerCast(CE0->getOperand(0),
IntPtrTy, false);
Constant *Null = Constant::getNullValue(C->getType());
return ConstantFoldCompareInstOperands(Predicate, C, Null, TD);
}
if (CE0->getOpcode() == Instruction::PtrToInt &&
CE0->getType() == IntPtrTy) {
Constant *C = CE0->getOperand(0);
Constant *Null = Constant::getNullValue(C->getType());
return ConstantFoldCompareInstOperands(Predicate, C, Null, TD);
}
}
if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(Ops1)) {
if (TD && CE0->getOpcode() == CE1->getOpcode()) {
const Type *IntPtrTy = TD->getIntPtrType(CE0->getContext());
if (CE0->getOpcode() == Instruction::IntToPtr) {
Constant *C0 = ConstantExpr::getIntegerCast(CE0->getOperand(0),
IntPtrTy, false);
Constant *C1 = ConstantExpr::getIntegerCast(CE1->getOperand(0),
IntPtrTy, false);
return ConstantFoldCompareInstOperands(Predicate, C0, C1, TD);
}
if ((CE0->getOpcode() == Instruction::PtrToInt &&
CE0->getType() == IntPtrTy &&
CE0->getOperand(0)->getType() == CE1->getOperand(0)->getType()))
return ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(0),
CE1->getOperand(0), TD);
}
}
if ((Predicate == ICmpInst::ICMP_EQ || Predicate == ICmpInst::ICMP_NE) &&
CE0->getOpcode() == Instruction::Or && Ops1->isNullValue()) {
Constant *LHS =
ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(0), Ops1,TD);
Constant *RHS =
ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(1), Ops1,TD);
unsigned OpC =
Predicate == ICmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
Constant *Ops[] = { LHS, RHS };
return ConstantFoldInstOperands(OpC, LHS->getType(), Ops, 2, TD);
}
}
return ConstantExpr::getCompare(Predicate, Ops0, Ops1);
}
Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C,
ConstantExpr *CE) {
if (CE->getOperand(1) != Constant::getNullValue(CE->getOperand(1)->getType()))
return 0;
gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
for (++I; I != E; ++I)
if (const StructType *STy = dyn_cast<StructType>(*I)) {
ConstantInt *CU = cast<ConstantInt>(I.getOperand());
assert(CU->getZExtValue() < STy->getNumElements() &&
"Struct index out of range!");
unsigned El = (unsigned)CU->getZExtValue();
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
C = CS->getOperand(El);
} else if (isa<ConstantAggregateZero>(C)) {
C = Constant::getNullValue(STy->getElementType(El));
} else if (isa<UndefValue>(C)) {
C = UndefValue::get(STy->getElementType(El));
} else {
return 0;
}
} else if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand())) {
if (const ArrayType *ATy = dyn_cast<ArrayType>(*I)) {
if (CI->getZExtValue() >= ATy->getNumElements())
return 0;
if (ConstantArray *CA = dyn_cast<ConstantArray>(C))
C = CA->getOperand(CI->getZExtValue());
else if (isa<ConstantAggregateZero>(C))
C = Constant::getNullValue(ATy->getElementType());
else if (isa<UndefValue>(C))
C = UndefValue::get(ATy->getElementType());
else
return 0;
} else if (const VectorType *VTy = dyn_cast<VectorType>(*I)) {
if (CI->getZExtValue() >= VTy->getNumElements())
return 0;
if (ConstantVector *CP = dyn_cast<ConstantVector>(C))
C = CP->getOperand(CI->getZExtValue());
else if (isa<ConstantAggregateZero>(C))
C = Constant::getNullValue(VTy->getElementType());
else if (isa<UndefValue>(C))
C = UndefValue::get(VTy->getElementType());
else
return 0;
} else {
return 0;
}
} else {
return 0;
}
return C;
}
bool
llvm::canConstantFoldCallTo(const Function *F) {
switch (F->getIntrinsicID()) {
case Intrinsic::sqrt:
case Intrinsic::powi:
case Intrinsic::bswap:
case Intrinsic::ctpop:
case Intrinsic::ctlz:
case Intrinsic::cttz:
case Intrinsic::sadd_with_overflow:
case Intrinsic::uadd_with_overflow:
case Intrinsic::ssub_with_overflow:
case Intrinsic::usub_with_overflow:
case Intrinsic::smul_with_overflow:
case Intrinsic::umul_with_overflow:
case Intrinsic::convert_from_fp16:
case Intrinsic::convert_to_fp16:
case Intrinsic::x86_sse_cvtss2si:
case Intrinsic::x86_sse_cvtss2si64:
case Intrinsic::x86_sse_cvttss2si:
case Intrinsic::x86_sse_cvttss2si64:
case Intrinsic::x86_sse2_cvtsd2si:
case Intrinsic::x86_sse2_cvtsd2si64:
case Intrinsic::x86_sse2_cvttsd2si:
case Intrinsic::x86_sse2_cvttsd2si64:
return true;
default:
return false;
case 0: break;
}
if (!F->hasName()) return false;
StringRef Name = F->getName();
switch (Name[0]) {
default: return false;
case 'a':
return Name == "acos" || Name == "asin" ||
Name == "atan" || Name == "atan2";
case 'c':
return Name == "cos" || Name == "ceil" || Name == "cosf" || Name == "cosh";
case 'e':
return Name == "exp";
case 'f':
return Name == "fabs" || Name == "fmod" || Name == "floor";
case 'l':
return Name == "log" || Name == "log10";
case 'p':
return Name == "pow";
case 's':
return Name == "sin" || Name == "sinh" || Name == "sqrt" ||
Name == "sinf" || Name == "sqrtf";
case 't':
return Name == "tan" || Name == "tanh";
}
}
static Constant *ConstantFoldFP(double (*NativeFP)(double), double V,
const Type *Ty) {
sys::llvm_fenv_clearexcept();
V = NativeFP(V);
if (sys::llvm_fenv_testexcept()) {
sys::llvm_fenv_clearexcept();
return 0;
}
if (Ty->isFloatTy())
return ConstantFP::get(Ty->getContext(), APFloat((float)V));
if (Ty->isDoubleTy())
return ConstantFP::get(Ty->getContext(), APFloat(V));
llvm_unreachable("Can only constant fold float/double");
return 0; }
static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double),
double V, double W, const Type *Ty) {
sys::llvm_fenv_clearexcept();
V = NativeFP(V, W);
if (sys::llvm_fenv_testexcept()) {
sys::llvm_fenv_clearexcept();
return 0;
}
if (Ty->isFloatTy())
return ConstantFP::get(Ty->getContext(), APFloat((float)V));
if (Ty->isDoubleTy())
return ConstantFP::get(Ty->getContext(), APFloat(V));
llvm_unreachable("Can only constant fold float/double");
return 0; }
static Constant *ConstantFoldConvertToInt(ConstantFP *Op, bool roundTowardZero,
const Type *Ty) {
assert(Op && "Called with NULL operand");
APFloat Val(Op->getValueAPF());
unsigned ResultWidth = cast<IntegerType>(Ty)->getBitWidth();
assert(ResultWidth <= 64 &&
"Can only constant fold conversions to 64 and 32 bit ints");
uint64_t UIntVal;
bool isExact = false;
APFloat::roundingMode mode = roundTowardZero? APFloat::rmTowardZero
: APFloat::rmNearestTiesToEven;
APFloat::opStatus status = Val.convertToInteger(&UIntVal, ResultWidth,
true, mode,
&isExact);
if (status != APFloat::opOK && status != APFloat::opInexact)
return 0;
return ConstantInt::get(Ty, UIntVal, true);
}
Constant *
llvm::ConstantFoldCall(Function *F,
Constant *const *Operands, unsigned NumOperands) {
if (!F->hasName()) return 0;
StringRef Name = F->getName();
const Type *Ty = F->getReturnType();
if (NumOperands == 1) {
if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) {
if (F->getIntrinsicID() == Intrinsic::convert_to_fp16) {
APFloat Val(Op->getValueAPF());
bool lost = false;
Val.convert(APFloat::IEEEhalf, APFloat::rmNearestTiesToEven, &lost);
return ConstantInt::get(F->getContext(), Val.bitcastToAPInt());
}
if (!Ty->isFloatTy() && !Ty->isDoubleTy())
return 0;
if (Op->getValueAPF().isNaN() || Op->getValueAPF().isInfinity())
return 0;
double V = Ty->isFloatTy() ? (double)Op->getValueAPF().convertToFloat() :
Op->getValueAPF().convertToDouble();
switch (Name[0]) {
case 'a':
if (Name == "acos")
return ConstantFoldFP(acos, V, Ty);
else if (Name == "asin")
return ConstantFoldFP(asin, V, Ty);
else if (Name == "atan")
return ConstantFoldFP(atan, V, Ty);
break;
case 'c':
if (Name == "ceil")
return ConstantFoldFP(ceil, V, Ty);
else if (Name == "cos")
return ConstantFoldFP(cos, V, Ty);
else if (Name == "cosh")
return ConstantFoldFP(cosh, V, Ty);
else if (Name == "cosf")
return ConstantFoldFP(cos, V, Ty);
break;
case 'e':
if (Name == "exp")
return ConstantFoldFP(exp, V, Ty);
break;
case 'f':
if (Name == "fabs")
return ConstantFoldFP(fabs, V, Ty);
else if (Name == "floor")
return ConstantFoldFP(floor, V, Ty);
break;
case 'l':
if (Name == "log" && V > 0)
return ConstantFoldFP(log, V, Ty);
else if (Name == "log10" && V > 0)
return ConstantFoldFP(log10, V, Ty);
else if (F->getIntrinsicID() == Intrinsic::sqrt &&
(Ty->isFloatTy() || Ty->isDoubleTy())) {
if (V >= -0.0)
return ConstantFoldFP(sqrt, V, Ty);
else return Constant::getNullValue(Ty);
}
break;
case 's':
if (Name == "sin")
return ConstantFoldFP(sin, V, Ty);
else if (Name == "sinh")
return ConstantFoldFP(sinh, V, Ty);
else if (Name == "sqrt" && V >= 0)
return ConstantFoldFP(sqrt, V, Ty);
else if (Name == "sqrtf" && V >= 0)
return ConstantFoldFP(sqrt, V, Ty);
else if (Name == "sinf")
return ConstantFoldFP(sin, V, Ty);
break;
case 't':
if (Name == "tan")
return ConstantFoldFP(tan, V, Ty);
else if (Name == "tanh")
return ConstantFoldFP(tanh, V, Ty);
break;
default:
break;
}
return 0;
}
if (ConstantInt *Op = dyn_cast<ConstantInt>(Operands[0])) {
switch (F->getIntrinsicID()) {
case Intrinsic::bswap:
return ConstantInt::get(F->getContext(), Op->getValue().byteSwap());
case Intrinsic::ctpop:
return ConstantInt::get(Ty, Op->getValue().countPopulation());
case Intrinsic::cttz:
return ConstantInt::get(Ty, Op->getValue().countTrailingZeros());
case Intrinsic::ctlz:
return ConstantInt::get(Ty, Op->getValue().countLeadingZeros());
case Intrinsic::convert_from_fp16: {
APFloat Val(Op->getValue());
bool lost = false;
APFloat::opStatus status =
Val.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven, &lost);
(void)status;
assert(status == APFloat::opOK && !lost &&
"Precision lost during fp16 constfolding");
return ConstantFP::get(F->getContext(), Val);
}
default:
return 0;
}
}
if (ConstantVector *Op = dyn_cast<ConstantVector>(Operands[0])) {
switch (F->getIntrinsicID()) {
default: break;
case Intrinsic::x86_sse_cvtss2si:
case Intrinsic::x86_sse_cvtss2si64:
case Intrinsic::x86_sse2_cvtsd2si:
case Intrinsic::x86_sse2_cvtsd2si64:
if (ConstantFP *FPOp = dyn_cast<ConstantFP>(Op->getOperand(0)))
return ConstantFoldConvertToInt(FPOp, false, Ty);
case Intrinsic::x86_sse_cvttss2si:
case Intrinsic::x86_sse_cvttss2si64:
case Intrinsic::x86_sse2_cvttsd2si:
case Intrinsic::x86_sse2_cvttsd2si64:
if (ConstantFP *FPOp = dyn_cast<ConstantFP>(Op->getOperand(0)))
return ConstantFoldConvertToInt(FPOp, true, Ty);
}
}
if (isa<UndefValue>(Operands[0])) {
if (F->getIntrinsicID() == Intrinsic::bswap)
return Operands[0];
return 0;
}
return 0;
}
if (NumOperands == 2) {
if (ConstantFP *Op1 = dyn_cast<ConstantFP>(Operands[0])) {
if (!Ty->isFloatTy() && !Ty->isDoubleTy())
return 0;
double Op1V = Ty->isFloatTy() ?
(double)Op1->getValueAPF().convertToFloat() :
Op1->getValueAPF().convertToDouble();
if (ConstantFP *Op2 = dyn_cast<ConstantFP>(Operands[1])) {
if (Op2->getType() != Op1->getType())
return 0;
double Op2V = Ty->isFloatTy() ?
(double)Op2->getValueAPF().convertToFloat():
Op2->getValueAPF().convertToDouble();
if (Name == "pow")
return ConstantFoldBinaryFP(pow, Op1V, Op2V, Ty);
if (Name == "fmod")
return ConstantFoldBinaryFP(fmod, Op1V, Op2V, Ty);
if (Name == "atan2")
return ConstantFoldBinaryFP(atan2, Op1V, Op2V, Ty);
} else if (ConstantInt *Op2C = dyn_cast<ConstantInt>(Operands[1])) {
if (F->getIntrinsicID() == Intrinsic::powi && Ty->isFloatTy())
return ConstantFP::get(F->getContext(),
APFloat((float)std::pow((float)Op1V,
(int)Op2C->getZExtValue())));
if (F->getIntrinsicID() == Intrinsic::powi && Ty->isDoubleTy())
return ConstantFP::get(F->getContext(),
APFloat((double)std::pow((double)Op1V,
(int)Op2C->getZExtValue())));
}
return 0;
}
if (ConstantInt *Op1 = dyn_cast<ConstantInt>(Operands[0])) {
if (ConstantInt *Op2 = dyn_cast<ConstantInt>(Operands[1])) {
switch (F->getIntrinsicID()) {
default: break;
case Intrinsic::sadd_with_overflow:
case Intrinsic::uadd_with_overflow:
case Intrinsic::ssub_with_overflow:
case Intrinsic::usub_with_overflow:
case Intrinsic::smul_with_overflow:
case Intrinsic::umul_with_overflow: {
APInt Res;
bool Overflow;
switch (F->getIntrinsicID()) {
default: assert(0 && "Invalid case");
case Intrinsic::sadd_with_overflow:
Res = Op1->getValue().sadd_ov(Op2->getValue(), Overflow);
break;
case Intrinsic::uadd_with_overflow:
Res = Op1->getValue().uadd_ov(Op2->getValue(), Overflow);
break;
case Intrinsic::ssub_with_overflow:
Res = Op1->getValue().ssub_ov(Op2->getValue(), Overflow);
break;
case Intrinsic::usub_with_overflow:
Res = Op1->getValue().usub_ov(Op2->getValue(), Overflow);
break;
case Intrinsic::smul_with_overflow:
Res = Op1->getValue().smul_ov(Op2->getValue(), Overflow);
break;
case Intrinsic::umul_with_overflow:
Res = Op1->getValue().umul_ov(Op2->getValue(), Overflow);
break;
}
Constant *Ops[] = {
ConstantInt::get(F->getContext(), Res),
ConstantInt::get(Type::getInt1Ty(F->getContext()), Overflow)
};
return ConstantStruct::get(F->getContext(), Ops, 2, false);
}
}
}
return 0;
}
return 0;
}
return 0;
}