-//===-- ConstantFolding.cpp - Analyze constant folding possibilities ------===//
+//===-- ConstantFolding.cpp - Fold instructions into constants ------------===//
//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// This family of functions determines the possibility of performing constant
-// folding.
+// This file defines routines for folding instructions into constants.
+//
+// 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
+// dependency issues.
//
//===----------------------------------------------------------------------===//
#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/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/System/FEnv.h"
#include <cerrno>
#include <cmath>
using namespace llvm;
//===----------------------------------------------------------------------===//
-// Constant Folding ...
-//
+// 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
+/// ConstantExpr if unfoldable.
+static Constant *FoldBitCast(Constant *C, const Type *DestTy,
+ const TargetData &TD) {
+
+ // This only handles casts to vectors currently.
+ const VectorType *DestVTy = dyn_cast<VectorType>(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<ConstantFP>(C) || isa<ConstantInt>(C)) {
+ Constant *Ops = C; // don't take the address of C!
+ return FoldBitCast(ConstantVector::get(&Ops, 1), DestTy, TD);
+ }
+
+ // If this is a bitcast from constant vector -> vector, fold it.
+ ConstantVector *CV = dyn_cast<ConstantVector>(C);
+ if (CV == 0)
+ return ConstantExpr::getBitCast(C, DestTy);
+
+ // If the element types match, VMCore can fold it.
+ 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();
+
+ // 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> <i64 0, i64 1> to <4 x i32>)
+ // folds to (little endian):
+ // <4 x i32> <i32 0, i32 0, i32 1, i32 0>
+ // and to (big endian):
+ // <4 x i32> <i32 0, i32 0, i32 0, i32 1>
+
+ // 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()) {
+ // Fold to an vector of integers with same size as our FP type.
+ unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits();
+ const Type *DestIVTy =
+ VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumDstElt);
+ // Recursively handle this integer conversion, if possible.
+ C = FoldBitCast(C, DestIVTy, TD);
+ if (!C) return ConstantExpr::getBitCast(C, DestTy);
+
+ // 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()) {
+ unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits();
+ const Type *SrcIVTy =
+ VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElt);
+ // Ask VMCore to do the conversion now that #elts line up.
+ C = ConstantExpr::getBitCast(C, SrcIVTy);
+ CV = dyn_cast<ConstantVector>(C);
+ if (!CV) // If VMCore wasn't able to fold it, bail out.
+ 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<Constant*, 32> Result;
+ if (NumDstElt < NumSrcElt) {
+ // Handle: bitcast (<4 x i32> <i32 0, i32 1, i32 2, i32 3> to <2 x i64>)
+ Constant *Zero = Constant::getNullValue(DstEltTy);
+ unsigned Ratio = NumSrcElt/NumDstElt;
+ unsigned SrcBitSize = SrcEltTy->getPrimitiveSizeInBits();
+ unsigned SrcElt = 0;
+ for (unsigned i = 0; i != NumDstElt; ++i) {
+ // Build each element of the result.
+ 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) // 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,
+ ConstantInt::get(Src->getType(), ShiftAmt));
+ ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize;
+
+ // Mix it in.
+ Elt = ConstantExpr::getOr(Elt, Src);
+ }
+ Result.push_back(Elt);
+ }
+ } else {
+ // Handle: bitcast (<2 x i64> <i64 0, i64 1> 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<ConstantInt>(CV->getOperand(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,
+ 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.data(), Result.size());
+}
+
+
+/// IsConstantOffsetFromGlobal - If this constant is actually a constant offset
+/// 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) {
+ // Trivial case, constant is the global.
+ if ((GV = dyn_cast<GlobalValue>(C))) {
+ Offset = 0;
+ return true;
+ }
+
+ // Otherwise, if this isn't a constant expr, bail out.
+ ConstantExpr *CE = dyn_cast<ConstantExpr>(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)
+ if (CE->getOpcode() == Instruction::GetElementPtr) {
+ // Cannot compute this if the element type of the pointer is missing size
+ // info.
+ if (!cast<PointerType>(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();
+ i != e; ++i, ++GTI) {
+ ConstantInt *CI = dyn_cast<ConstantInt>(*i);
+ if (!CI) return false; // Index isn't a simple constant?
+ if (CI->isZero()) continue; // Not adding anything.
+
+ if (const StructType *ST = dyn_cast<StructType>(*GTI)) {
+ // N = N + Offset
+ 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;
+}
+
+/// ReadDataFromGlobal - Recursive helper to read bits out of global. C is the
+/// constant being copied out of. ByteOffset is an offset into C. CurPtr is the
+/// pointer to copy results into and BytesLeft is the number of bytes left in
+/// the CurPtr buffer. TD is the target data.
+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 this element is zero or undefined, we can just return since *CurPtr is
+ // zero initialized.
+ 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) {
+ // If the element access is to the element itself and not to tail padding,
+ // read the bytes from the element.
+ uint64_t EltSize = TD.getTypeAllocSize(CS->getOperand(Index)->getType());
+
+ if (ByteOffset < EltSize &&
+ !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;
+
+ // If we read all of the bytes we needed from this element we're done.
+ uint64_t NextEltOffset = SL->getElementOffset(Index);
+
+ if (BytesLeft <= NextEltOffset-CurEltOffset-ByteOffset)
+ return true;
+
+ // Move to the next element of the struct.
+ CurPtr += NextEltOffset-CurEltOffset-ByteOffset;
+ BytesLeft -= NextEltOffset-CurEltOffset-ByteOffset;
+ ByteOffset = 0;
+ CurEltOffset = NextEltOffset;
+ }
+ // not reached.
+ }
+
+ 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;
+ }
+
+ // Otherwise, unknown initializer type.
+ 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 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
+ // and then bitcast the result. This can be useful for union cases. Note
+ // that address spaces don't matter here since we're not going to result in
+ // an actual new load.
+ 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 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];
+ }
+
+ return ConstantInt::get(IntType->getContext(), ResultVal);
+}
+
+/// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
+/// produce if it is constant and determinable. If this is not determinable,
+/// return null.
+Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C,
+ const TargetData *TD) {
+ // First, try the easy cases:
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
+ if (GV->isConstant() && GV->hasDefinitiveInitializer())
+ return GV->getInitializer();
+
+ // If the loaded value isn't a constant expr, we can't handle it.
+ 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;
+ }
+
+ // 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();
+ const Type *Ty = cast<PointerType>(CE->getType())->getElementType();
+ unsigned NumBits = Ty->getPrimitiveSizeInBits();
+ // Replace load with immediate integer if the result is an integer or fp
+ // value.
+ 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;
+ }
+ // Append NULL at the end.
+ 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 = dyn_cast<GlobalVariable>(CE->getUnderlyingObject())){
+ 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);
+ }
+ }
+
+ // 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())
+ 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;
+}
+
+/// 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,
+/// otherwise TD is null.
+static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
+ Constant *Op1, const TargetData *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) {
+ // (&GV+C1) - (&GV+C2) -> C1-C2, pointer arithmetic cannot overflow.
+ return ConstantInt::get(Op0->getType(), Offs1-Offs2);
+ }
+ }
+
+ return 0;
+}
+
+/// CastGEPIndices - If array indices are not pointer-sized integers,
+/// explicitly cast them so that they aren't implicitly casted by the
+/// getelementptr.
+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;
+}
+
+/// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP
+/// constant expression, do so.
+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;
+
+ unsigned BitWidth =
+ TD->getTypeSizeInBits(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; i != NumOps; ++i)
+ if (!isa<ConstantInt>(Ops[i]))
+ return 0;
+
+ APInt Offset = APInt(BitWidth,
+ TD->getIndexedOffset(Ptr->getType(),
+ (Value**)Ops+1, NumOps-1));
+ Ptr = cast<Constant>(Ptr->stripPointerCasts());
+
+ // If this is a GEP of a GEP, fold it all into a single GEP.
+ while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
+ SmallVector<Value *, 4> NestedOps(GEP->op_begin()+1, GEP->op_end());
+
+ // Do not try the incorporate the sub-GEP if some index is not a number.
+ 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());
+ }
+
+ // If the base value for this address is a literal integer value, fold the
+ // getelementptr to the resulting integer value casted to the pointer type.
+ 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();
+ BasePtr.zextOrTrunc(BitWidth);
+ }
+ if (Ptr->isNullValue() || BasePtr != 0) {
+ Constant *C = ConstantInt::get(Ptr->getContext(), Offset+BasePtr);
+ return ConstantExpr::getIntToPtr(C, ResultTy);
+ }
+
+ // Otherwise form a regular getelementptr. Recompute the indices so that
+ // we eliminate over-indexing of the notional static type array bounds.
+ // This makes it easy to determine if the getelementptr is "inbounds".
+ // Also, this helps GlobalOpt do SROA on GlobalVariables.
+ const Type *Ty = Ptr->getType();
+ SmallVector<Constant*, 32> NewIdxs;
+ do {
+ if (const SequentialType *ATy = dyn_cast<SequentialType>(Ty)) {
+ if (ATy->isPointerTy()) {
+ // 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()));
+ if (ElemSize == 0)
+ return 0;
+ APInt NewIdx = Offset.udiv(ElemSize);
+ Offset -= NewIdx * ElemSize;
+ NewIdxs.push_back(ConstantInt::get(TD->getIntPtrType(Ty->getContext()),
+ NewIdx));
+ Ty = ATy->getElementType();
+ } else if (const StructType *STy = dyn_cast<StructType>(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.
+ 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 {
+ // We've reached some non-indexable type.
+ break;
+ }
+ } while (Ty != cast<PointerType>(ResultTy)->getElementType());
+
+ // If we haven't used up the entire offset by descending the static
+ // type, then the offset is pointing into the middle of an indivisible
+ // member, so we can't simplify it.
+ if (Offset != 0)
+ return 0;
+
+ // Create a GEP.
+ Constant *C =
+ ConstantExpr::getGetElementPtr(Ptr, &NewIdxs[0], NewIdxs.size());
+ assert(cast<PointerType>(C->getType())->getElementType() == Ty &&
+ "Computed GetElementPtr has unexpected type!");
+
+ // If we ended up indexing a member with a type that doesn't match
+ // the type of what the original indices indexed, add a cast.
+ if (Ty != cast<PointerType>(ResultTy)->getElementType())
+ C = FoldBitCast(C, ResultTy, *TD);
+
+ return C;
+}
+
+
+
+//===----------------------------------------------------------------------===//
+// Constant Folding public APIs
+//===----------------------------------------------------------------------===//
+/// ConstantFoldInstruction - Attempt to constant fold the specified
+/// instruction. If successful, the constant result is returned, if not, null
+/// is returned. Note that 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) {
+ // Handle PHI nodes specially here...
+ 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 the incoming value is equal to the phi node itself or is undef then
+ // skip it.
+ if (Incoming == PN || isa<UndefValue>(Incoming))
+ continue;
+ // If the incoming value is not a constant, or is a different constant to
+ // the one we saw previously, then give up.
+ Constant *C = dyn_cast<Constant>(Incoming);
+ if (!C || (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());
+ }
+
+ // Scan the operand list, checking to see if they are all constants, if so,
+ // hand off to ConstantFoldInstOperands.
+ 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; // All operands not constant!
+
+ 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);
+
+ return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
+ Ops.data(), Ops.size(), TD);
+}
+
+/// ConstantFoldConstantExpression - Attempt to fold the constant expression
+/// using the specified TargetData. If successful, the constant result is
+/// result is returned, if not, null is returned.
+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);
+ // Recursively fold the ConstantExpr's operands.
+ 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);
+}
+
+/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
+/// specified opcode and operands. If successful, the constant result is
+/// returned, if not, null is returned. Note that this function can fail when
+/// attempting to fold instructions like loads and stores, which have no
+/// constant expression form.
+///
+/// TODO: This function neither utilizes nor preserves nsw/nuw/inbounds/etc
+/// information, due to only being passed an opcode and operands. Constant
+/// folding using this function strips this information.
+///
+Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
+ Constant* const* Ops, unsigned NumOps,
+ const TargetData *TD) {
+ // Handle easy binops first.
+ 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 the input is a inttoptr, eliminate the pair. This requires knowing
+ // the width of a pointer, so it can't be done in ConstantExpr::getCast.
+ 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);
+ }
+ // Do a zext or trunc to get to the dest size.
+ return ConstantExpr::getIntegerCast(Input, DestTy, false);
+ }
+ }
+ return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
+ case Instruction::IntToPtr:
+ // If the input is a ptrtoint, turn the pair into a ptr to ptr bitcast if
+ // the int size is >= the ptr size. This requires knowing the width of a
+ // pointer, so it can't be done in ConstantExpr::getCast.
+ 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);
+ }
+}
+
+/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
+/// instruction (icmp/fcmp) with the specified operands. If it fails, it
+/// returns a constant expression of the specified operands.
+///
+Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate,
+ Constant *Ops0, Constant *Ops1,
+ const TargetData *TD) {
+ // fold: icmp (inttoptr x), null -> icmp x, 0
+ // fold: icmp (ptrtoint x), 0 -> icmp x, null
+ // fold: icmp (inttoptr x), (inttoptr y) -> icmp trunc/zext x, trunc/zext y
+ // fold: icmp (ptrtoint x), (ptrtoint y) -> icmp x, y
+ //
+ // ConstantExpr::getCompare cannot do this, because it doesn't have TD
+ // around to know if bit truncation is happening.
+ if (ConstantExpr *CE0 = dyn_cast<ConstantExpr>(Ops0)) {
+ if (TD && Ops1->isNullValue()) {
+ const Type *IntPtrTy = TD->getIntPtrType(CE0->getContext());
+ if (CE0->getOpcode() == Instruction::IntToPtr) {
+ // Convert the integer value to the right size to ensure we get the
+ // proper extension or truncation.
+ Constant *C = ConstantExpr::getIntegerCast(CE0->getOperand(0),
+ IntPtrTy, false);
+ Constant *Null = Constant::getNullValue(C->getType());
+ return ConstantFoldCompareInstOperands(Predicate, C, Null, TD);
+ }
+
+ // 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 &&
+ 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) {
+ // Convert the integer value to the right size to ensure we get the
+ // proper extension or truncation.
+ Constant *C0 = ConstantExpr::getIntegerCast(CE0->getOperand(0),
+ IntPtrTy, false);
+ Constant *C1 = ConstantExpr::getIntegerCast(CE1->getOperand(0),
+ IntPtrTy, false);
+ return ConstantFoldCompareInstOperands(Predicate, C0, C1, TD);
+ }
+
+ // 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 &&
+ CE0->getType() == IntPtrTy &&
+ CE0->getOperand(0)->getType() == CE1->getOperand(0)->getType()))
+ return ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(0),
+ CE1->getOperand(0), TD);
+ }
+ }
+
+ // 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 =
+ 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);
+}
+
+
+/// 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,
+ ConstantExpr *CE) {
+ if (CE->getOperand(1) != Constant::getNullValue(CE->getOperand(1)->getType()))
+ return 0; // Do not allow stepping over the value!
+
+ // Loop over all of the operands, tracking down which value we are
+ // addressing...
+ 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;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Constant Folding for Calls
+//
+
/// canConstantFoldCallTo - Return true if its even possible to fold a call to
/// the specified function.
bool
-llvm::canConstantFoldCallTo(Function *F) {
- const std::string &Name = F->getName();
-
+llvm::canConstantFoldCallTo(const Function *F) {
switch (F->getIntrinsicID()) {
- case Intrinsic::isunordered_f32:
- case Intrinsic::isunordered_f64:
- case Intrinsic::sqrt_f32:
- case Intrinsic::sqrt_f64:
- case Intrinsic::bswap_i16:
- case Intrinsic::bswap_i32:
- case Intrinsic::bswap_i64:
- // FIXME: these should be constant folded as well
- //case Intrinsic::ctpop_i8:
- //case Intrinsic::ctpop_i16:
- //case Intrinsic::ctpop_i32:
- //case Intrinsic::ctpop_i64:
- //case Intrinsic::ctlz_i8:
- //case Intrinsic::ctlz_i16:
- //case Intrinsic::ctlz_i32:
- //case Intrinsic::ctlz_i64:
- //case Intrinsic::cttz_i8:
- //case Intrinsic::cttz_i16:
- //case Intrinsic::cttz_i32:
- //case Intrinsic::cttz_i64:
+ case Intrinsic::sqrt:
+ case Intrinsic::powi:
+ case Intrinsic::bswap:
+ case Intrinsic::ctpop:
+ case Intrinsic::ctlz:
+ case Intrinsic::cttz:
+ case Intrinsic::uadd_with_overflow:
+ case Intrinsic::usub_with_overflow:
+ case Intrinsic::sadd_with_overflow:
+ case Intrinsic::ssub_with_overflow:
+ case Intrinsic::smul_with_overflow:
+ case Intrinsic::convert_from_fp16:
+ case Intrinsic::convert_to_fp16:
return true;
- default: break;
- }
-
- switch (Name[0])
- {
- case 'a':
- return Name == "acos" || Name == "asin" || Name == "atan" ||
- Name == "atan2";
- case 'c':
- return Name == "ceil" || Name == "cos" || 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 == "sqrtf";
- case 't':
- return Name == "tan" || Name == "tanh";
- default:
- return false;
+ default:
+ return false;
+ case 0: break;
+ }
+
+ 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" ||
+ 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";
}
}
-Constant *
-llvm::ConstantFoldFP(double (*NativeFP)(double), double V, const Type *Ty) {
- errno = 0;
+static Constant *ConstantFoldFP(double (*NativeFP)(double), double V,
+ const Type *Ty) {
+ sys::llvm_fenv_clearexcept();
V = NativeFP(V);
- if (errno == 0)
- return ConstantFP::get(Ty, V);
- return 0;
+ 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; // dummy return to suppress warning
+}
+
+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; // dummy return to suppress warning
}
/// ConstantFoldCall - Attempt to constant fold a call to the specified function
/// with the specified arguments, returning null if unsuccessful.
Constant *
-llvm::ConstantFoldCall(Function *F, const std::vector<Constant*> &Operands) {
- const std::string &Name = F->getName();
- const Type *Ty = F->getReturnType();
+llvm::ConstantFoldCall(Function *F,
+ Constant *const *Operands, unsigned NumOperands) {
+ if (!F->hasName()) return 0;
+ StringRef Name = F->getName();
- if (Operands.size() == 1) {
+ const Type *Ty = F->getReturnType();
+ if (NumOperands == 1) {
if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) {
- double V = Op->getValue();
- 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 ConstantFP::get(Ty, atan(V));
- break;
- case 'c':
- if (Name == "ceil")
- return ConstantFoldFP(ceil, V, Ty);
- else if (Name == "cos")
- return ConstantFP::get(Ty, cos(V));
- else if (Name == "cosh")
- return ConstantFP::get(Ty, cosh(V));
- break;
- case 'e':
- if (Name == "exp")
- return ConstantFP::get(Ty, exp(V));
- break;
- case 'f':
- if (Name == "fabs")
- return ConstantFP::get(Ty, fabs(V));
- else if (Name == "floor")
- return ConstantFoldFP(floor, V, Ty);
- break;
- case 'l':
- if (Name == "log" && V > 0)
- return ConstantFP::get(Ty, log(V));
- else if (Name == "log10" && V > 0)
- return ConstantFoldFP(log10, V, Ty);
- else if (Name == "llvm.sqrt.f32" || Name == "llvm.sqrt.f64") {
- if (V >= -0.0)
- return ConstantFP::get(Ty, sqrt(V));
- else // Undefined
- return ConstantFP::get(Ty, 0.0);
- }
- break;
- case 's':
- if (Name == "sin")
- return ConstantFP::get(Ty, sin(V));
- else if (Name == "sinh")
- return ConstantFP::get(Ty, sinh(V));
- else if (Name == "sqrt" && V >= 0)
- return ConstantFP::get(Ty, sqrt(V));
- else if (Name == "sqrtf" && V >= 0)
- return ConstantFP::get(Ty, sqrt((float)V));
- break;
- case 't':
- if (Name == "tan")
- return ConstantFP::get(Ty, tan(V));
- else if (Name == "tanh")
- return ConstantFP::get(Ty, tanh(V));
- break;
- default:
- break;
+ if (Name == "llvm.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;
+
+ /// We only fold functions with finite arguments. Folding NaN and inf is
+ /// likely to be aborted with an exception anyway, and some host libms
+ /// have known errors raising exceptions.
+ if (Op->getValueAPF().isNaN() || Op->getValueAPF().isInfinity())
+ return 0;
+
+ /// Currently APFloat versions of these functions do not exist, so we use
+ /// the host native double versions. Float versions are not called
+ /// directly but for all these it is true (float)(f((double)arg)) ==
+ /// f(arg). Long double not supported yet.
+ 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 (Name == "llvm.sqrt.f32" ||
+ Name == "llvm.sqrt.f64") {
+ if (V >= -0.0)
+ return ConstantFoldFP(sqrt, V, Ty);
+ else // Undefined
+ 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;
}
- } else if (ConstantUInt *Op = dyn_cast<ConstantUInt>(Operands[0])) {
- uint64_t V = Op->getValue();
- if (Name == "llvm.bswap.i16")
- return ConstantUInt::get(Ty, ByteSwap_16(V));
- else if (Name == "llvm.bswap.i32")
- return ConstantUInt::get(Ty, ByteSwap_32(V));
- else if (Name == "llvm.bswap.i64")
- return ConstantUInt::get(Ty, ByteSwap_64(V));
+ return 0;
}
- } else if (Operands.size() == 2) {
+
+
+ if (ConstantInt *Op = dyn_cast<ConstantInt>(Operands[0])) {
+ if (Name.startswith("llvm.bswap"))
+ return ConstantInt::get(F->getContext(), Op->getValue().byteSwap());
+ else if (Name.startswith("llvm.ctpop"))
+ return ConstantInt::get(Ty, Op->getValue().countPopulation());
+ else if (Name.startswith("llvm.cttz"))
+ return ConstantInt::get(Ty, Op->getValue().countTrailingZeros());
+ else if (Name.startswith("llvm.ctlz"))
+ return ConstantInt::get(Ty, Op->getValue().countLeadingZeros());
+ else if (Name == "llvm.convert.from.fp16") {
+ APFloat Val(Op->getValue());
+
+ bool lost = false;
+ APFloat::opStatus status =
+ Val.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven, &lost);
+
+ // Conversion is always precise.
+ status = status;
+ assert(status == APFloat::opOK && !lost &&
+ "Precision lost during fp16 constfolding");
+
+ return ConstantFP::get(F->getContext(), Val);
+ }
+ return 0;
+ }
+
+ if (isa<UndefValue>(Operands[0])) {
+ if (Name.startswith("llvm.bswap"))
+ return Operands[0];
+ return 0;
+ }
+
+ return 0;
+ }
+
+ if (NumOperands == 2) {
if (ConstantFP *Op1 = dyn_cast<ConstantFP>(Operands[0])) {
- double Op1V = Op1->getValue();
+ 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])) {
- double Op2V = Op2->getValue();
+ if (Op2->getType() != Op1->getType())
+ return 0;
+
+ double Op2V = Ty->isFloatTy() ?
+ (double)Op2->getValueAPF().convertToFloat():
+ Op2->getValueAPF().convertToDouble();
- if (Name == "llvm.isunordered.f32" || Name == "llvm.isunordered.f64")
- return ConstantBool::get(IsNAN(Op1V) || IsNAN(Op2V));
- else
- if (Name == "pow") {
- errno = 0;
- double V = pow(Op1V, Op2V);
- if (errno == 0)
- return ConstantFP::get(Ty, V);
- } else if (Name == "fmod") {
- errno = 0;
- double V = fmod(Op1V, Op2V);
- if (errno == 0)
- return ConstantFP::get(Ty, V);
- } else if (Name == "atan2")
- return ConstantFP::get(Ty, atan2(Op1V,Op2V));
+ 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 (Name == "llvm.powi.f32")
+ return ConstantFP::get(F->getContext(),
+ APFloat((float)std::pow((float)Op1V,
+ (int)Op2C->getZExtValue())));
+ if (Name == "llvm.powi.f64")
+ 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: {
+ 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;
+ }
+ 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;
}
projects / oota-llvm.git / blobdiff