X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FConstantFolding.cpp;h=91a5b84e8a635410db1a00307fad21dfdcb2285c;hb=b341fac05a890272024dcc5c7e47d10b22d62b92;hp=fe28926f1b2c4c657f1c6ed3ca50481a750521f6;hpb=6b0dc92043ab1f63d78b8796098575e1d777b701;p=oota-llvm.git diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp index fe28926f1b2..91a5b84e8a6 100644 --- a/lib/Analysis/ConstantFolding.cpp +++ b/lib/Analysis/ConstantFolding.cpp @@ -11,7 +11,7 @@ // // Also, to supplement the basic VMCore ConstantExpr simplifications, // this file defines some additional folding routines that can make use of -// TargetData information. These functions cannot go in VMCore due to library +// DataLayout information. These functions cannot go in VMCore due to library // dependency issues. // //===----------------------------------------------------------------------===// @@ -25,7 +25,7 @@ #include "llvm/Intrinsics.h" #include "llvm/Operator.h" #include "llvm/Analysis/ValueTracking.h" -#include "llvm/Target/TargetData.h" +#include "llvm/DataLayout.h" #include "llvm/Target/TargetLibraryInfo.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringMap.h" @@ -41,51 +41,86 @@ using namespace llvm; // Constant Folding internal helper functions //===----------------------------------------------------------------------===// -/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with -/// TargetData. This always returns a non-null constant, but it may be a +/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with +/// DataLayout. This always returns a non-null constant, but it may be a /// ConstantExpr if unfoldable. static Constant *FoldBitCast(Constant *C, Type *DestTy, - const TargetData &TD) { + const DataLayout &TD) { // Catch the obvious splat cases. if (C->isNullValue() && !DestTy->isX86_MMXTy()) return Constant::getNullValue(DestTy); if (C->isAllOnesValue() && !DestTy->isX86_MMXTy()) return Constant::getAllOnesValue(DestTy); + // Handle a vector->integer cast. + if (IntegerType *IT = dyn_cast(DestTy)) { + ConstantDataVector *CDV = dyn_cast(C); + if (CDV == 0) + return ConstantExpr::getBitCast(C, DestTy); + + unsigned NumSrcElts = CDV->getType()->getNumElements(); + + Type *SrcEltTy = CDV->getType()->getElementType(); + + // If the vector is a vector of floating point, convert it to vector of int + // to simplify things. + if (SrcEltTy->isFloatingPointTy()) { + unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits(); + Type *SrcIVTy = + VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElts); + // Ask VMCore to do the conversion now that #elts line up. + C = ConstantExpr::getBitCast(C, SrcIVTy); + CDV = cast(C); + } + + // Now that we know that the input value is a vector of integers, just shift + // and insert them into our result. + unsigned BitShift = TD.getTypeAllocSizeInBits(SrcEltTy); + APInt Result(IT->getBitWidth(), 0); + for (unsigned i = 0; i != NumSrcElts; ++i) { + Result <<= BitShift; + if (TD.isLittleEndian()) + Result |= CDV->getElementAsInteger(NumSrcElts-i-1); + else + Result |= CDV->getElementAsInteger(i); + } + + return ConstantInt::get(IT, Result); + } + // The code below only handles casts to vectors currently. VectorType *DestVTy = dyn_cast(DestTy); if (DestVTy == 0) return ConstantExpr::getBitCast(C, DestTy); - + // If this is a scalar -> vector cast, convert the input into a <1 x scalar> // vector so the code below can handle it uniformly. if (isa(C) || isa(C)) { Constant *Ops = C; // don't take the address of C! return FoldBitCast(ConstantVector::get(Ops), DestTy, TD); } - + // If this is a bitcast from constant vector -> vector, fold it. - // FIXME: Remove ConstantVector support. if (!isa(C) && !isa(C)) return ConstantExpr::getBitCast(C, DestTy); - + // If the element types match, VMCore can fold it. unsigned NumDstElt = DestVTy->getNumElements(); unsigned NumSrcElt = C->getType()->getVectorNumElements(); if (NumDstElt == NumSrcElt) return ConstantExpr::getBitCast(C, DestTy); - + Type *SrcEltTy = C->getType()->getVectorElementType(); Type *DstEltTy = DestVTy->getElementType(); - - // Otherwise, we're changing the number of elements in a vector, which + + // Otherwise, we're changing the number of elements in a vector, which // requires endianness information to do the right thing. For example, // bitcast (<2 x i64> to <4 x i32>) // folds to (little endian): // <4 x i32> // and to (big endian): // <4 x i32> - + // First thing is first. We only want to think about integer here, so if // we have something in FP form, recast it as integer. if (DstEltTy->isFloatingPointTy()) { @@ -95,11 +130,11 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumDstElt); // Recursively handle this integer conversion, if possible. C = FoldBitCast(C, DestIVTy, TD); - + // Finally, VMCore can handle this now that #elts line up. return ConstantExpr::getBitCast(C, DestTy); } - + // Okay, we know the destination is integer, if the input is FP, convert // it to integer first. if (SrcEltTy->isFloatingPointTy()) { @@ -113,13 +148,13 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, !isa(C)) return C; } - + // Now we know that the input and output vectors are both integer vectors // of the same size, and that their #elements is not the same. Do the // conversion here, which depends on whether the input or output has // more elements. bool isLittleEndian = TD.isLittleEndian(); - + SmallVector Result; if (NumDstElt < NumSrcElt) { // Handle: bitcast (<4 x i32> to <2 x i64>) @@ -135,15 +170,15 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, Constant *Src =dyn_cast(C->getAggregateElement(SrcElt++)); if (!Src) // Reject constantexpr elements. return ConstantExpr::getBitCast(C, DestTy); - + // Zero extend the element to the right size. Src = ConstantExpr::getZExt(Src, Elt->getType()); - + // Shift it to the right place, depending on endianness. - Src = ConstantExpr::getShl(Src, + Src = ConstantExpr::getShl(Src, ConstantInt::get(Src->getType(), ShiftAmt)); ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize; - + // Mix it in. Elt = ConstantExpr::getOr(Elt, Src); } @@ -151,30 +186,30 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, } return ConstantVector::get(Result); } - + // Handle: bitcast (<2 x i64> to <4 x i32>) unsigned Ratio = NumDstElt/NumSrcElt; unsigned DstBitSize = DstEltTy->getPrimitiveSizeInBits(); - + // Loop over each source value, expanding into multiple results. for (unsigned i = 0; i != NumSrcElt; ++i) { Constant *Src = dyn_cast(C->getAggregateElement(i)); if (!Src) // Reject constantexpr elements. return ConstantExpr::getBitCast(C, DestTy); - + unsigned ShiftAmt = isLittleEndian ? 0 : DstBitSize*(Ratio-1); for (unsigned j = 0; j != Ratio; ++j) { // Shift the piece of the value into the right place, depending on // endianness. - Constant *Elt = ConstantExpr::getLShr(Src, + Constant *Elt = ConstantExpr::getLShr(Src, ConstantInt::get(Src->getType(), ShiftAmt)); ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize; - + // Truncate and remember this piece. Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy)); } } - + return ConstantVector::get(Result); } @@ -183,34 +218,34 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, /// from a global, return the global and the constant. Because of /// constantexprs, this function is recursive. static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, - int64_t &Offset, const TargetData &TD) { + int64_t &Offset, const DataLayout &TD) { // Trivial case, constant is the global. if ((GV = dyn_cast(C))) { Offset = 0; return true; } - + // Otherwise, if this isn't a constant expr, bail out. ConstantExpr *CE = dyn_cast(C); if (!CE) return false; - + // Look through ptr->int and ptr->ptr casts. if (CE->getOpcode() == Instruction::PtrToInt || CE->getOpcode() == Instruction::BitCast) return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD); - - // i32* getelementptr ([5 x i32]* @a, i32 0, i32 5) + + // i32* getelementptr ([5 x i32]* @a, i32 0, i32 5) if (CE->getOpcode() == Instruction::GetElementPtr) { // Cannot compute this if the element type of the pointer is missing size // info. if (!cast(CE->getOperand(0)->getType()) ->getElementType()->isSized()) return false; - + // If the base isn't a global+constant, we aren't either. if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD)) return false; - + // Otherwise, add any offset that our operands provide. gep_type_iterator GTI = gep_type_begin(CE); for (User::const_op_iterator i = CE->op_begin() + 1, e = CE->op_end(); @@ -218,7 +253,7 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, ConstantInt *CI = dyn_cast(*i); if (!CI) return false; // Index isn't a simple constant? if (CI->isZero()) continue; // Not adding anything. - + if (StructType *ST = dyn_cast(*GTI)) { // N = N + Offset Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()); @@ -229,7 +264,7 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, } return true; } - + return false; } @@ -239,30 +274,33 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, /// the CurPtr buffer. TD is the target data. static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, unsigned char *CurPtr, unsigned BytesLeft, - const TargetData &TD) { + const DataLayout &TD) { assert(ByteOffset <= TD.getTypeAllocSize(C->getType()) && "Out of range access"); - + // If this element is zero or undefined, we can just return since *CurPtr is // zero initialized. if (isa(C) || isa(C)) return true; - + if (ConstantInt *CI = dyn_cast(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)); + int n = ByteOffset; + if (!TD.isLittleEndian()) + n = IntBytes - n - 1; + CurPtr[i] = (unsigned char)(Val >> (n * 8)); ++ByteOffset; } return true; } - + if (ConstantFP *CFP = dyn_cast(C)) { if (CFP->getType()->isDoubleTy()) { C = FoldBitCast(C, Type::getInt64Ty(C->getContext()), TD); @@ -274,13 +312,13 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, } return false; } - + if (ConstantStruct *CS = dyn_cast(C)) { const StructLayout *SL = TD.getStructLayout(CS->getType()); unsigned Index = SL->getElementContainingOffset(ByteOffset); uint64_t CurEltOffset = SL->getElementOffset(Index); ByteOffset -= CurEltOffset; - + while (1) { // If the element access is to the element itself and not to tail padding, // read the bytes from the element. @@ -290,9 +328,9 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, !ReadDataFromGlobal(CS->getOperand(Index), ByteOffset, CurPtr, BytesLeft, TD)) return false; - + ++Index; - + // Check to see if we read from the last struct element, if so we're done. if (Index == CS->getType()->getNumElements()) return true; @@ -312,7 +350,6 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, // not reached. } - // FIXME: Remove ConstantVector if (isa(C) || isa(C) || isa(C)) { Type *EltTy = cast(C->getType())->getElementType(); @@ -324,25 +361,28 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, NumElts = AT->getNumElements(); else NumElts = cast(C->getType())->getNumElements(); - + for (; Index != NumElts; ++Index) { if (!ReadDataFromGlobal(C->getAggregateElement(Index), Offset, CurPtr, BytesLeft, TD)) return false; - if (EltSize >= BytesLeft) + + uint64_t BytesWritten = EltSize - Offset; + assert(BytesWritten <= EltSize && "Not indexing into this element?"); + if (BytesWritten >= BytesLeft) return true; - + Offset = 0; - BytesLeft -= EltSize; - CurPtr += EltSize; + BytesLeft -= BytesWritten; + CurPtr += BytesWritten; } return true; } - + if (ConstantExpr *CE = dyn_cast(C)) { if (CE->getOpcode() == Instruction::IntToPtr && - CE->getOperand(0)->getType() == TD.getIntPtrType(CE->getContext())) - return ReadDataFromGlobal(CE->getOperand(0), ByteOffset, CurPtr, + CE->getOperand(0)->getType() == TD.getIntPtrType(CE->getContext())) + return ReadDataFromGlobal(CE->getOperand(0), ByteOffset, CurPtr, BytesLeft, TD); } @@ -351,10 +391,10 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, } static Constant *FoldReinterpretLoadFromConstPtr(Constant *C, - const TargetData &TD) { + const DataLayout &TD) { Type *LoadTy = cast(C->getType())->getElementType(); IntegerType *IntType = dyn_cast(LoadTy); - + // If this isn't an integer load we can't fold it directly. if (!IntType) { // If this is a float/double load, we can try folding it as an int32/64 load @@ -378,15 +418,15 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C, 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(GVal); if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() || !GV->getInitializer()->getType()->isSized()) @@ -395,20 +435,29 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C, // If we're loading off the beginning of the global, some bytes may be valid, // but we don't try to handle this. if (Offset < 0) return 0; - + // If we're not accessing anything in this constant, the result is undefined. 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]; + APInt ResultVal = APInt(IntType->getBitWidth(), 0); + if (TD.isLittleEndian()) { + ResultVal = RawBytes[BytesLoaded - 1]; + for (unsigned i = 1; i != BytesLoaded; ++i) { + ResultVal <<= 8; + ResultVal |= RawBytes[BytesLoaded-1-i]; + } + } else { + ResultVal = RawBytes[0]; + for (unsigned i = 1; i != BytesLoaded; ++i) { + ResultVal <<= 8; + ResultVal |= RawBytes[i]; + } } return ConstantInt::get(IntType->getContext(), ResultVal); @@ -418,7 +467,7 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C, /// produce if it is constant and determinable. If this is not determinable, /// return null. Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, - const TargetData *TD) { + const DataLayout *TD) { // First, try the easy cases: if (GlobalVariable *GV = dyn_cast(C)) if (GV->isConstant() && GV->hasDefinitiveInitializer()) @@ -427,20 +476,20 @@ Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, // If the loaded value isn't a constant expr, we can't handle it. ConstantExpr *CE = dyn_cast(C); if (!CE) return 0; - + if (CE->getOpcode() == Instruction::GetElementPtr) { if (GlobalVariable *GV = dyn_cast(CE->getOperand(0))) if (GV->isConstant() && GV->hasDefinitiveInitializer()) - if (Constant *V = + if (Constant *V = ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE)) return V; } - + // Instead of loading constant c string, use corresponding integer value // directly if string length is small enough. - std::string Str; - if (TD && GetConstantStringInfo(CE, Str) && !Str.empty()) { - unsigned StrLen = Str.length(); + StringRef Str; + if (TD && getConstantStringInfo(CE, Str) && !Str.empty()) { + unsigned StrLen = Str.size(); Type *Ty = cast(CE->getType())->getElementType(); unsigned NumBits = Ty->getPrimitiveSizeInBits(); // Replace load with immediate integer if the result is an integer or fp @@ -463,14 +512,14 @@ Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, SingleChar = 0; StrVal = (StrVal << 8) | SingleChar; } - + Constant *Res = ConstantInt::get(CE->getContext(), StrVal); if (Ty->isFloatingPointTy()) Res = ConstantExpr::getBitCast(Res, Ty); return Res; } } - + // If this load comes from anywhere in a constant global, and if the global // is all undef or zero, we know what it loads. if (GlobalVariable *GV = @@ -483,18 +532,16 @@ Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, return UndefValue::get(ResTy); } } - - // Try hard to fold loads from bitcasted strange and non-type-safe things. We - // currently don't do any of this for big endian systems. It can be - // generalized in the future if someone is interested. - if (TD && TD->isLittleEndian()) + + // Try hard to fold loads from bitcasted strange and non-type-safe things. + if (TD) return FoldReinterpretLoadFromConstPtr(CE, *TD); return 0; } -static Constant *ConstantFoldLoadInst(const LoadInst *LI, const TargetData *TD){ +static Constant *ConstantFoldLoadInst(const LoadInst *LI, const DataLayout *TD){ if (LI->isVolatile()) return 0; - + if (Constant *C = dyn_cast(LI->getOperand(0))) return ConstantFoldLoadFromConstPtr(C, TD); @@ -503,23 +550,23 @@ static Constant *ConstantFoldLoadInst(const LoadInst *LI, const TargetData *TD){ /// SymbolicallyEvaluateBinop - One of Op0/Op1 is a constant expression. /// Attempt to symbolically evaluate the result of a binary operator merging -/// these together. If target data info is available, it is provided as TD, +/// these together. If target data info is available, it is provided as TD, /// otherwise TD is null. static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, - Constant *Op1, const TargetData *TD){ + Constant *Op1, const DataLayout *TD){ // SROA - + // Fold (and 0xffffffff00000000, (shl x, 32)) -> shl. // Fold (lshr (or X, Y), 32) -> (lshr [X/Y], 32) if one doesn't contribute // bits. - - + + // If the constant expr is something like &A[123] - &A[4].f, fold this into a // constant. This happens frequently when iterating over a global array. 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) { @@ -527,7 +574,7 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, return ConstantInt::get(Op0->getType(), Offs1-Offs2); } } - + return 0; } @@ -535,7 +582,7 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, /// explicitly cast them so that they aren't implicitly casted by the /// getelementptr. static Constant *CastGEPIndices(ArrayRef Ops, - Type *ResultTy, const TargetData *TD, + Type *ResultTy, const DataLayout *TD, const TargetLibraryInfo *TLI) { if (!TD) return 0; Type *IntPtrTy = TD->getIntPtrType(ResultTy->getContext()); @@ -566,23 +613,39 @@ static Constant *CastGEPIndices(ArrayRef Ops, return C; } +/// Strip the pointer casts, but preserve the address space information. +static Constant* StripPtrCastKeepAS(Constant* Ptr) { + assert(Ptr->getType()->isPointerTy() && "Not a pointer type"); + PointerType *OldPtrTy = cast(Ptr->getType()); + Ptr = cast(Ptr->stripPointerCasts()); + PointerType *NewPtrTy = cast(Ptr->getType()); + + // Preserve the address space number of the pointer. + if (NewPtrTy->getAddressSpace() != OldPtrTy->getAddressSpace()) { + NewPtrTy = NewPtrTy->getElementType()->getPointerTo( + OldPtrTy->getAddressSpace()); + Ptr = ConstantExpr::getBitCast(Ptr, NewPtrTy); + } + return Ptr; +} + /// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP /// constant expression, do so. static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, - Type *ResultTy, const TargetData *TD, + Type *ResultTy, const DataLayout *TD, const TargetLibraryInfo *TLI) { Constant *Ptr = Ops[0]; if (!TD || !cast(Ptr->getType())->getElementType()->isSized() || !Ptr->getType()->isPointerTy()) return 0; - + Type *IntPtrTy = TD->getIntPtrType(Ptr->getContext()); // If this is a constant expr gep that is effectively computing an // "offsetof", fold it into 'cast int Size to T*' instead of 'gep 0, 0, 12' for (unsigned i = 1, e = Ops.size(); i != e; ++i) if (!isa(Ops[i])) { - + // If this is "gep i8* Ptr, (sub 0, V)", fold this as: // "inttoptr (sub (ptrtoint Ptr), V)" if (Ops.size() == 2 && @@ -602,13 +665,14 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, } return 0; } - + unsigned BitWidth = TD->getTypeSizeInBits(IntPtrTy); APInt Offset = APInt(BitWidth, TD->getIndexedOffset(Ptr->getType(), - makeArrayRef((Value **)Ops.data() + 1, + makeArrayRef((Value *const*) + Ops.data() + 1, Ops.size() - 1))); - Ptr = cast(Ptr->stripPointerCasts()); + Ptr = StripPtrCastKeepAS(Ptr); // If this is a GEP of a GEP, fold it all into a single GEP. while (GEPOperator *GEP = dyn_cast(Ptr)) { @@ -627,7 +691,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, Ptr = cast(GEP->getOperand(0)); Offset += APInt(BitWidth, TD->getIndexedOffset(Ptr->getType(), NestedOps)); - Ptr = cast(Ptr->stripPointerCasts()); + Ptr = StripPtrCastKeepAS(Ptr); } // If the base value for this address is a literal integer value, fold the @@ -647,6 +711,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, // This makes it easy to determine if the getelementptr is "inbounds". // Also, this helps GlobalOpt do SROA on GlobalVariables. Type *Ty = Ptr->getType(); + assert(Ty->isPointerTy() && "Forming regular GEP of non-pointer type"); SmallVector NewIdxs; do { if (SequentialType *ATy = dyn_cast(Ty)) { @@ -654,12 +719,12 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, // The only pointer indexing we'll do is on the first index of the GEP. if (!NewIdxs.empty()) break; - + // Only handle pointers to sized types, not pointers to functions. if (!ATy->getElementType()->isSized()) return 0; } - + // Determine which element of the array the offset points into. APInt ElemSize(BitWidth, TD->getTypeAllocSize(ATy->getElementType())); IntegerType *IntPtrTy = TD->getIntPtrType(Ty->getContext()); @@ -677,10 +742,17 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, } Ty = ATy->getElementType(); } else if (StructType *STy = dyn_cast(Ty)) { - // Determine which field of the struct the offset points into. The - // getZExtValue is at least as safe as the StructLayout API because we - // know the offset is within the struct at this point. + // If we end up with an offset that isn't valid for this struct type, we + // can't re-form this GEP in a regular form, so bail out. The pointer + // operand likely went through casts that are necessary to make the GEP + // sensible. const StructLayout &SL = *TD->getStructLayout(STy); + if (Offset.uge(SL.getSizeInBytes())) + break; + + // Determine which field of the struct the offset points into. The + // getZExtValue is fine as we've already ensured that the offset is + // within the range representable by the StructLayout API. unsigned ElIdx = SL.getElementContainingOffset(Offset.getZExtValue()); NewIdxs.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()), ElIdx)); @@ -724,7 +796,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef Ops, /// this function can only fail when attempting to fold instructions like loads /// and stores, which have no constant expression form. Constant *llvm::ConstantFoldInstruction(Instruction *I, - const TargetData *TD, + const DataLayout *TD, const TargetLibraryInfo *TLI) { // Handle PHI nodes quickly here... if (PHINode *PN = dyn_cast(I)) { @@ -738,14 +810,21 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, // all operands are constants. if (isa(Incoming)) continue; - // If the incoming value is not a constant, or is a different constant to - // the one we saw previously, then give up. + // If the incoming value is not a constant, then give up. Constant *C = dyn_cast(Incoming); - if (!C || (CommonValue && C != CommonValue)) + if (!C) + return 0; + // Fold the PHI's operands. + if (ConstantExpr *NewC = dyn_cast(C)) + C = ConstantFoldConstantExpression(NewC, TD, TLI); + // If the incoming value is a different constant to + // the one we saw previously, then give up. + if (CommonValue && C != CommonValue) return 0; CommonValue = C; } + // If we reach here, all incoming values are the same constant or undef. return CommonValue ? CommonValue : UndefValue::get(PN->getType()); } @@ -753,16 +832,22 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, // Scan the operand list, checking to see if they are all constants, if so, // hand off to ConstantFoldInstOperands. SmallVector Ops; - for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) - if (Constant *Op = dyn_cast(*i)) - Ops.push_back(Op); - else + for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) { + Constant *Op = dyn_cast(*i); + if (!Op) return 0; // All operands not constant! + // Fold the Instruction's operands. + if (ConstantExpr *NewCE = dyn_cast(Op)) + Op = ConstantFoldConstantExpression(NewCE, TD, TLI); + + Ops.push_back(Op); + } + if (const CmpInst *CI = dyn_cast(I)) return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1], TD, TLI); - + if (const LoadInst *LI = dyn_cast(I)) return ConstantFoldLoadInst(LI, TD); @@ -781,10 +866,10 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, } /// ConstantFoldConstantExpression - Attempt to fold the constant expression -/// using the specified TargetData. If successful, the constant result is +/// using the specified DataLayout. If successful, the constant result is /// result is returned, if not, null is returned. Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE, - const TargetData *TD, + const DataLayout *TD, const TargetLibraryInfo *TLI) { SmallVector Ops; for (User::const_op_iterator i = CE->op_begin(), e = CE->op_end(); @@ -812,23 +897,23 @@ Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE, /// information, due to only being passed an opcode and operands. Constant /// folding using this function strips this information. /// -Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, +Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, ArrayRef Ops, - const TargetData *TD, - const TargetLibraryInfo *TLI) { + const DataLayout *TD, + const TargetLibraryInfo *TLI) { // Handle easy binops first. if (Instruction::isBinaryOp(Opcode)) { if (isa(Ops[0]) || isa(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::FCmp: llvm_unreachable("Invalid for compares"); case Instruction::Call: if (Function *F = dyn_cast(Ops.back())) if (canConstantFoldCallTo(F)) @@ -842,7 +927,7 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, Constant *Input = CE->getOperand(0); unsigned InWidth = Input->getType()->getScalarSizeInBits(); if (TD->getPointerSizeInBits() < InWidth) { - Constant *Mask = + Constant *Mask = ConstantInt::get(CE->getContext(), APInt::getLowBitsSet(InWidth, TD->getPointerSizeInBits())); Input = ConstantExpr::getAnd(Input, Mask); @@ -890,7 +975,7 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, return C; if (Constant *C = SymbolicallyEvaluateGEP(Ops, DestTy, TD, TLI)) return C; - + return ConstantExpr::getGetElementPtr(Ops[0], Ops.slice(1)); } } @@ -900,8 +985,8 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, /// returns a constant expression of the specified operands. /// Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, - Constant *Ops0, Constant *Ops1, - const TargetData *TD, + Constant *Ops0, Constant *Ops1, + const DataLayout *TD, const TargetLibraryInfo *TLI) { // fold: icmp (inttoptr x), null -> icmp x, 0 // fold: icmp (ptrtoint x), 0 -> icmp x, null @@ -921,17 +1006,17 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, Constant *Null = Constant::getNullValue(C->getType()); return ConstantFoldCompareInstOperands(Predicate, C, Null, TD, TLI); } - + // Only do this transformation if the int is intptrty in size, otherwise // there is a truncation or extension that we aren't modeling. - if (CE0->getOpcode() == Instruction::PtrToInt && + 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, TLI); } } - + if (ConstantExpr *CE1 = dyn_cast(Ops1)) { if (TD && CE0->getOpcode() == CE1->getOpcode()) { Type *IntPtrTy = TD->getIntPtrType(CE0->getContext()); @@ -955,24 +1040,24 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, CE1->getOperand(0), TD, TLI); } } - + // icmp eq (or x, y), 0 -> (icmp eq x, 0) & (icmp eq y, 0) // icmp ne (or x, y), 0 -> (icmp ne x, 0) | (icmp ne y, 0) if ((Predicate == ICmpInst::ICMP_EQ || Predicate == ICmpInst::ICMP_NE) && CE0->getOpcode() == Instruction::Or && Ops1->isNullValue()) { - Constant *LHS = + Constant *LHS = ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(0), Ops1, TD, TLI); - Constant *RHS = + Constant *RHS = ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(1), Ops1, TD, TLI); - unsigned OpC = + unsigned OpC = Predicate == ICmpInst::ICMP_EQ ? Instruction::And : Instruction::Or; Constant *Ops[] = { LHS, RHS }; return ConstantFoldInstOperands(OpC, LHS->getType(), Ops, TD, TLI); } } - + return ConstantExpr::getCompare(Predicate, Ops0, Ops1); } @@ -980,7 +1065,7 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, /// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a /// getelementptr constantexpr, return the constant value being addressed by the /// constant expression, or null if something is funny and we can't decide. -Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C, +Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE) { if (!CE->getOperand(1)->isNullValue()) return 0; // Do not allow stepping over the value! @@ -1050,14 +1135,14 @@ llvm::canConstantFoldCallTo(const Function *F) { if (!F->hasName()) return false; StringRef Name = F->getName(); - + // In these cases, the check of the length is required. We don't want to // return true for a name like "cos\0blah" which strcmp would return equal to // "cos", but has length 8. switch (Name[0]) { default: return false; case 'a': - return Name == "acos" || Name == "asin" || + return Name == "acos" || Name == "asin" || Name == "atan" || Name == "atan2"; case 'c': return Name == "cos" || Name == "ceil" || Name == "cosf" || Name == "cosh"; @@ -1077,7 +1162,7 @@ llvm::canConstantFoldCallTo(const Function *F) { } } -static Constant *ConstantFoldFP(double (*NativeFP)(double), double V, +static Constant *ConstantFoldFP(double (*NativeFP)(double), double V, Type *Ty) { sys::llvm_fenv_clearexcept(); V = NativeFP(V); @@ -1085,7 +1170,7 @@ static Constant *ConstantFoldFP(double (*NativeFP)(double), double V, sys::llvm_fenv_clearexcept(); return 0; } - + if (Ty->isFloatTy()) return ConstantFP::get(Ty->getContext(), APFloat((float)V)); if (Ty->isDoubleTy()) @@ -1101,7 +1186,7 @@ static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), sys::llvm_fenv_clearexcept(); return 0; } - + if (Ty->isFloatTy()) return ConstantFP::get(Ty->getContext(), APFloat((float)V)); if (Ty->isDoubleTy()) @@ -1195,7 +1280,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, case 'e': if (Name == "exp" && TLI->has(LibFunc::exp)) return ConstantFoldFP(exp, V, Ty); - + if (Name == "exp2" && TLI->has(LibFunc::exp2)) { // Constant fold exp2(x) as pow(2,x) in case the host doesn't have a // C99 library. @@ -1271,7 +1356,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, } // Support ConstantVector in case we have an Undef in the top. - if (isa(Operands[0]) || + if (isa(Operands[0]) || isa(Operands[0])) { Constant *Op = cast(Operands[0]); switch (F->getIntrinsicID()) { @@ -1290,11 +1375,11 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, case Intrinsic::x86_sse2_cvttsd2si64: if (ConstantFP *FPOp = dyn_cast_or_null(Op->getAggregateElement(0U))) - return ConstantFoldConvertToInt(FPOp->getValueAPF(), + return ConstantFoldConvertToInt(FPOp->getValueAPF(), /*roundTowardZero=*/true, Ty); } } - + if (isa(Operands[0])) { if (F->getIntrinsicID() == Intrinsic::bswap) return Operands[0]; @@ -1308,14 +1393,14 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, if (ConstantFP *Op1 = dyn_cast(Operands[0])) { if (!Ty->isFloatTy() && !Ty->isDoubleTy()) return 0; - double Op1V = Ty->isFloatTy() ? + double Op1V = Ty->isFloatTy() ? (double)Op1->getValueAPF().convertToFloat() : Op1->getValueAPF().convertToDouble(); if (ConstantFP *Op2 = dyn_cast(Operands[1])) { if (Op2->getType() != Op1->getType()) return 0; - double Op2V = Ty->isFloatTy() ? + double Op2V = Ty->isFloatTy() ? (double)Op2->getValueAPF().convertToFloat(): Op2->getValueAPF().convertToDouble(); @@ -1342,7 +1427,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, } return 0; } - + if (ConstantInt *Op1 = dyn_cast(Operands[0])) { if (ConstantInt *Op2 = dyn_cast(Operands[1])) { switch (F->getIntrinsicID()) { @@ -1356,7 +1441,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, APInt Res; bool Overflow; switch (F->getIntrinsicID()) { - default: assert(0 && "Invalid case"); + default: llvm_unreachable("Invalid case"); case Intrinsic::sadd_with_overflow: Res = Op1->getValue().sadd_ov(Op2->getValue(), Overflow); break; @@ -1392,7 +1477,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef Operands, return ConstantInt::get(Ty, Op1->getValue().countLeadingZeros()); } } - + return 0; } return 0;