diff options
Diffstat (limited to 'lib/Analysis/ConstantFolding.cpp')
-rw-r--r-- | lib/Analysis/ConstantFolding.cpp | 240 |
1 files changed, 121 insertions, 119 deletions
diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp index 8e2f263..7a0a4e1 100644 --- a/lib/Analysis/ConstantFolding.cpp +++ b/lib/Analysis/ConstantFolding.cpp @@ -52,6 +52,42 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, if (C->isAllOnesValue() && !DestTy->isX86_MMXTy()) return Constant::getAllOnesValue(DestTy); + // Handle a vector->integer cast. + if (IntegerType *IT = dyn_cast<IntegerType>(DestTy)) { + ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(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<ConstantDataVector>(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<VectorType>(DestTy); if (DestVTy == 0) @@ -65,17 +101,16 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, } // If this is a bitcast from constant vector -> vector, fold it. - ConstantVector *CV = dyn_cast<ConstantVector>(C); - if (CV == 0) + if (!isa<ConstantDataVector>(C) && !isa<ConstantVector>(C)) return ConstantExpr::getBitCast(C, DestTy); // If the element types match, VMCore can fold it. unsigned NumDstElt = DestVTy->getNumElements(); - unsigned NumSrcElt = CV->getNumOperands(); + unsigned NumSrcElt = C->getType()->getVectorNumElements(); if (NumDstElt == NumSrcElt) return ConstantExpr::getBitCast(C, DestTy); - Type *SrcEltTy = CV->getType()->getElementType(); + Type *SrcEltTy = C->getType()->getVectorElementType(); Type *DstEltTy = DestVTy->getElementType(); // Otherwise, we're changing the number of elements in a vector, which @@ -95,7 +130,6 @@ 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); - if (!C) return ConstantExpr::getBitCast(C, DestTy); // Finally, VMCore can handle this now that #elts line up. return ConstantExpr::getBitCast(C, DestTy); @@ -109,8 +143,9 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, 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. + // If VMCore wasn't able to fold it, bail out. + if (!isa<ConstantVector>(C) && // FIXME: Remove ConstantVector. + !isa<ConstantDataVector>(C)) return C; } @@ -132,7 +167,7 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, 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++)); + Constant *Src =dyn_cast<ConstantInt>(C->getAggregateElement(SrcElt++)); if (!Src) // Reject constantexpr elements. return ConstantExpr::getBitCast(C, DestTy); @@ -149,28 +184,29 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy, } 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(); + return ConstantVector::get(Result); + } + + // 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>(C->getAggregateElement(i)); + if (!Src) // Reject constantexpr elements. + return ConstantExpr::getBitCast(C, DestTy); - // 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; - 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)); - } + // Truncate and remember this piece. + Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy)); } } @@ -273,7 +309,7 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, } return false; } - + if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) { const StructLayout *SL = TD.getStructLayout(CS->getType()); unsigned Index = SL->getElementContainingOffset(ByteOffset); @@ -311,12 +347,20 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, // not reached. } - if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) { - uint64_t EltSize = TD.getTypeAllocSize(CA->getType()->getElementType()); + if (isa<ConstantArray>(C) || isa<ConstantVector>(C) || + isa<ConstantDataSequential>(C)) { + Type *EltTy = cast<SequentialType>(C->getType())->getElementType(); + uint64_t EltSize = TD.getTypeAllocSize(EltTy); uint64_t Index = ByteOffset / EltSize; uint64_t Offset = ByteOffset - Index * EltSize; - for (; Index != CA->getType()->getNumElements(); ++Index) { - if (!ReadDataFromGlobal(CA->getOperand(Index), Offset, CurPtr, + uint64_t NumElts; + if (ArrayType *AT = dyn_cast<ArrayType>(C->getType())) + NumElts = AT->getNumElements(); + else + NumElts = cast<VectorType>(C->getType())->getNumElements(); + + for (; Index != NumElts; ++Index) { + if (!ReadDataFromGlobal(C->getAggregateElement(Index), Offset, CurPtr, BytesLeft, TD)) return false; if (EltSize >= BytesLeft) @@ -328,30 +372,12 @@ static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, } 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 ReadDataFromGlobal(CE->getOperand(0), ByteOffset, CurPtr, + BytesLeft, TD); } // Otherwise, unknown initializer type. @@ -446,9 +472,9 @@ Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, // 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<PointerType>(CE->getType())->getElementType(); unsigned NumBits = Ty->getPrimitiveSizeInBits(); // Replace load with immediate integer if the result is an integer or fp @@ -836,7 +862,7 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, 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<Function>(Ops.back())) if (canConstantFoldCallTo(F)) @@ -990,56 +1016,30 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, /// 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())) + if (!CE->getOperand(1)->isNullValue()) 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 (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 (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 (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; - } + // addressing. + for (unsigned i = 2, e = CE->getNumOperands(); i != e; ++i) { + C = C->getAggregateElement(CE->getOperand(i)); + if (C == 0) return 0; + } + return C; +} + +/// ConstantFoldLoadThroughGEPIndices - Given a constant and getelementptr +/// indices (with an *implied* zero pointer index that is not in the list), +/// return the constant value being addressed by a virtual load, or null if +/// something is funny and we can't decide. +Constant *llvm::ConstantFoldLoadThroughGEPIndices(Constant *C, + ArrayRef<Constant*> Indices) { + // Loop over all of the operands, tracking down which value we are + // addressing. + for (unsigned i = 0, e = Indices.size(); i != e; ++i) { + C = C->getAggregateElement(Indices[i]); + if (C == 0) return 0; + } return C; } @@ -1125,7 +1125,6 @@ static Constant *ConstantFoldFP(double (*NativeFP)(double), double 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), @@ -1142,7 +1141,6 @@ static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), 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 } /// ConstantFoldConvertToInt - Attempt to an SSE floating point to integer @@ -1153,11 +1151,8 @@ static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), /// available for the result. Returns null if the conversion cannot be /// performed, otherwise returns the Constant value resulting from the /// conversion. -static Constant *ConstantFoldConvertToInt(ConstantFP *Op, bool roundTowardZero, - Type *Ty) { - assert(Op && "Called with NULL operand"); - APFloat Val(Op->getValueAPF()); - +static Constant *ConstantFoldConvertToInt(const APFloat &Val, + bool roundTowardZero, Type *Ty) { // All of these conversion intrinsics form an integer of at most 64bits. unsigned ResultWidth = cast<IntegerType>(Ty)->getBitWidth(); assert(ResultWidth <= 64 && @@ -1309,24 +1304,31 @@ llvm::ConstantFoldCall(Function *F, ArrayRef<Constant *> Operands, } } - if (ConstantVector *Op = dyn_cast<ConstantVector>(Operands[0])) { + // Support ConstantVector in case we have an Undef in the top. + if (isa<ConstantVector>(Operands[0]) || + isa<ConstantDataVector>(Operands[0])) { + Constant *Op = cast<Constant>(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, /*roundTowardZero=*/false, Ty); + if (ConstantFP *FPOp = + dyn_cast_or_null<ConstantFP>(Op->getAggregateElement(0U))) + return ConstantFoldConvertToInt(FPOp->getValueAPF(), + /*roundTowardZero=*/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, /*roundTowardZero=*/true, Ty); + if (ConstantFP *FPOp = + dyn_cast_or_null<ConstantFP>(Op->getAggregateElement(0U))) + return ConstantFoldConvertToInt(FPOp->getValueAPF(), + /*roundTowardZero=*/true, Ty); } } - + if (isa<UndefValue>(Operands[0])) { if (F->getIntrinsicID() == Intrinsic::bswap) return Operands[0]; @@ -1388,7 +1390,7 @@ llvm::ConstantFoldCall(Function *F, ArrayRef<Constant *> 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; |