X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FConstantFolding.cpp;h=d4457b30318fcd631bb45f8226cd327aad724253;hb=ef4cfc749a61d0d0252196c957697436ba7ec068;hp=8c398462d408556b84b947853bfe64f42e03e903;hpb=f286f6fd93d569befe6e77c94a947e6e04e95685;p=oota-llvm.git diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp index 8c398462d40..d4457b30318 100644 --- a/lib/Analysis/ConstantFolding.cpp +++ b/lib/Analysis/ConstantFolding.cpp @@ -2,8 +2,8 @@ // // 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. // //===----------------------------------------------------------------------===// // @@ -65,8 +65,9 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, // Otherwise, add any offset that our operands provide. gep_type_iterator GTI = gep_type_begin(CE); - for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i, ++GTI) { - ConstantInt *CI = dyn_cast(CE->getOperand(i)); + for (User::const_op_iterator i = CE->op_begin() + 1, e = CE->op_end(); + i != e; ++i, ++GTI) { + ConstantInt *CI = dyn_cast(*i); if (!CI) return false; // Index isn't a simple constant? if (CI->getZExtValue() == 0) continue; // Not adding anything. @@ -75,7 +76,7 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()); } else { const SequentialType *SQT = cast(*GTI); - Offset += TD.getABITypeSize(SQT->getElementType())*CI->getSExtValue(); + Offset += TD.getTypePaddedSize(SQT->getElementType())*CI->getSExtValue(); } } return true; @@ -86,7 +87,7 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, /// SymbolicallyEvaluateBinop - One of Op0/Op1 is a constant expression. -/// Attempt to symbolically evaluate the result of a binary operator merging +/// 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, @@ -112,7 +113,6 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, } } - // TODO: Fold icmp setne/seteq as well. return 0; } @@ -122,23 +122,144 @@ static Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps, const Type *ResultTy, const TargetData *TD) { Constant *Ptr = Ops[0]; - if (!cast(Ptr->getType())->getElementType()->isSized()) + if (!TD || !cast(Ptr->getType())->getElementType()->isSized()) return 0; - if (TD && Ptr->isNullValue()) { - // 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' - bool isFoldableGEP = true; - for (unsigned i = 1; i != NumOps; ++i) - if (!isa(Ops[i])) { - isFoldableGEP = false; - break; + uint64_t BasePtr = 0; + if (!Ptr->isNullValue()) { + // If this is a inttoptr from a constant int, we can fold this as the base, + // otherwise we can't. + if (ConstantExpr *CE = dyn_cast(Ptr)) + if (CE->getOpcode() == Instruction::IntToPtr) + if (ConstantInt *Base = dyn_cast(CE->getOperand(0))) + BasePtr = Base->getZExtValue(); + + if (BasePtr == 0) + return 0; + } + + // 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(Ops[i])) + return false; + + uint64_t Offset = TD->getIndexedOffset(Ptr->getType(), + (Value**)Ops+1, NumOps-1); + Constant *C = ConstantInt::get(TD->getIntPtrType(), Offset+BasePtr); + return ConstantExpr::getIntToPtr(C, ResultTy); +} + +/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with +/// targetdata. Return 0 if unfoldable. +static Constant *FoldBitCast(Constant *C, const Type *DestTy, + const TargetData &TD) { + // If this is a bitcast from constant vector -> vector, fold it. + if (ConstantVector *CV = dyn_cast(C)) { + if (const VectorType *DestVTy = dyn_cast(DestTy)) { + // If the element types match, VMCore can fold it. + unsigned NumDstElt = DestVTy->getNumElements(); + unsigned NumSrcElt = CV->getNumOperands(); + if (NumDstElt == NumSrcElt) + return 0; + + 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> 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->isFloatingPoint()) { + // Fold to an vector of integers with same size as our FP type. + unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits(); + const Type *DestIVTy = VectorType::get(IntegerType::get(FPWidth), + NumDstElt); + // Recursively handle this integer conversion, if possible. + C = FoldBitCast(C, DestIVTy, TD); + if (!C) return 0; + + // 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->isFloatingPoint()) { + unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits(); + const Type *SrcIVTy = VectorType::get(IntegerType::get(FPWidth), + NumSrcElt); + // Ask VMCore to do the conversion now that #elts line up. + C = ConstantExpr::getBitCast(C, SrcIVTy); + CV = dyn_cast(C); + if (!CV) return 0; // If VMCore wasn't able to fold it, bail out. } - if (isFoldableGEP) { - uint64_t Offset = TD->getIndexedOffset(Ptr->getType(), - (Value**)Ops+1, NumOps-1); - Constant *C = ConstantInt::get(TD->getIntPtrType(), Offset); - return ConstantExpr::getIntToPtr(C, ResultTy); + + // 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>) + 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(CV->getOperand(SrcElt++)); + if (!Src) return 0; // Reject constantexpr elements. + + // 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> 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(CV->getOperand(i)); + if (!Src) return 0; // Reject constantexpr elements. + + 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[0], Result.size()); } } @@ -159,7 +280,7 @@ static Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps, Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { if (PHINode *PN = dyn_cast(I)) { if (PN->getNumIncomingValues() == 0) - return Constant::getNullValue(PN->getType()); + return UndefValue::get(PN->getType()); Constant *Result = dyn_cast(PN->getIncomingValue(0)); if (Result == 0) return 0; @@ -176,8 +297,8 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { // Scan the operand list, checking to see if they are all constants, if so, // hand off to ConstantFoldInstOperands. SmallVector Ops; - for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) - if (Constant *Op = dyn_cast(I->getOperand(i))) + 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 return 0; // All operands not constant! @@ -190,6 +311,25 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { &Ops[0], 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(ConstantExpr *CE, + const TargetData *TD) { + assert(TD && "ConstantFoldConstantExpression requires a valid TargetData."); + + SmallVector Ops; + for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i) + Ops.push_back(cast(*i)); + + if (CE->isCompare()) + return ConstantFoldCompareInstOperands(CE->getPredicate(), + &Ops[0], Ops.size(), TD); + else + return ConstantFoldInstOperands(CE->getOpcode(), CE->getType(), + &Ops[0], 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 @@ -217,6 +357,8 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy, return 0; case Instruction::ICmp: case Instruction::FCmp: + case Instruction::VICmp: + case Instruction::VFCmp: assert(0 &&"This function is invalid for compares: no predicate specified"); case Instruction::PtrToInt: // If the input is a inttoptr, eliminate the pair. This requires knowing @@ -225,16 +367,31 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy, if (TD && CE->getOpcode() == Instruction::IntToPtr) { Constant *Input = CE->getOperand(0); unsigned InWidth = Input->getType()->getPrimitiveSizeInBits(); - Constant *Mask = - ConstantInt::get(APInt::getLowBitsSet(InWidth, - TD->getPointerSizeInBits())); - Input = ConstantExpr::getAnd(Input, Mask); + if (TD->getPointerSizeInBits() < InWidth) { + Constant *Mask = + ConstantInt::get(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); } } - // FALL THROUGH. + 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(Ops[0])) { + if (TD && CE->getOpcode() == Instruction::PtrToInt && + TD->getPointerSizeInBits() <= + CE->getType()->getPrimitiveSizeInBits()) { + Constant *Input = CE->getOperand(0); + Constant *C = FoldBitCast(Input, DestTy, *TD); + return C ? C : ConstantExpr::getBitCast(Input, DestTy); + } + } + return ConstantExpr::getCast(Opcode, Ops[0], DestTy); case Instruction::Trunc: case Instruction::ZExt: case Instruction::SExt: @@ -244,8 +401,12 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy, case Instruction::SIToFP: case Instruction::FPToUI: case Instruction::FPToSI: + return ConstantExpr::getCast(Opcode, Ops[0], DestTy); case Instruction::BitCast: - return ConstantExpr::getCast(Opcode, Ops[0], DestTy); + if (TD) + if (Constant *C = FoldBitCast(Ops[0], DestTy, *TD)) + return C; + return ConstantExpr::getBitCast(Ops[0], DestTy); case Instruction::Select: return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]); case Instruction::ExtractElement: @@ -272,7 +433,7 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, 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 x, y + // 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 @@ -300,25 +461,35 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, } } - if (TD && isa(Ops[1]) && - cast(Ops[1])->getOpcode() == CE0->getOpcode()) { - const Type *IntPtrTy = TD->getIntPtrType(); - // 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::IntToPtr && - CE0->getOperand(0)->getType() == IntPtrTy && - CE0->getOperand(1)->getType() == IntPtrTy) || - (CE0->getOpcode() == Instruction::PtrToInt && - CE0->getType() == IntPtrTy && - CE0->getOperand(0)->getType() == CE0->getOperand(1)->getType())) { - Constant *NewOps[] = { - CE0->getOperand(0), cast(Ops[1])->getOperand(0) - }; - return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD); + if (ConstantExpr *CE1 = dyn_cast(Ops[1])) { + if (TD && CE0->getOpcode() == CE1->getOpcode()) { + const Type *IntPtrTy = TD->getIntPtrType(); + + 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); + Constant *NewOps[] = { C0, C1 }; + return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, 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())) { + Constant *NewOps[] = { + CE0->getOperand(0), CE1->getOperand(0) + }; + return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD); + } } } } - return ConstantExpr::getCompare(Predicate, Ops[0], Ops[1]); + return ConstantExpr::getCompare(Predicate, Ops[0], Ops[1]); } @@ -388,7 +559,7 @@ Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C, /// canConstantFoldCallTo - Return true if its even possible to fold a call to /// the specified function. bool -llvm::canConstantFoldCallTo(Function *F) { +llvm::canConstantFoldCallTo(const Function *F) { switch (F->getIntrinsicID()) { case Intrinsic::sqrt: case Intrinsic::powi: @@ -449,7 +620,8 @@ llvm::canConstantFoldCallTo(Function *F) { if (Len == 3) return !strcmp(Str, "sin"); if (Len == 4) - return !strcmp(Str, "sinh") || !strcmp(Str, "sqrt"); + return !strcmp(Str, "sinh") || !strcmp(Str, "sqrt") || + !strcmp(Str, "sinf"); if (Len == 5) return !strcmp(Str, "sqrtf"); return false; @@ -466,16 +638,17 @@ static Constant *ConstantFoldFP(double (*NativeFP)(double), double V, const Type *Ty) { errno = 0; V = NativeFP(V); - if (errno == 0) { - if (Ty==Type::FloatTy) - return ConstantFP::get(Ty, APFloat((float)V)); - else if (Ty==Type::DoubleTy) - return ConstantFP::get(Ty, APFloat(V)); - else - assert(0); + if (errno != 0) { + errno = 0; + return 0; } - errno = 0; - return 0; + + if (Ty == Type::FloatTy) + return ConstantFP::get(APFloat((float)V)); + if (Ty == Type::DoubleTy) + return ConstantFP::get(APFloat(V)); + assert(0 && "Can only constant fold float/double"); + return 0; // dummy return to suppress warning } static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), @@ -483,16 +656,17 @@ static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), const Type *Ty) { errno = 0; V = NativeFP(V, W); - if (errno == 0) { - if (Ty==Type::FloatTy) - return ConstantFP::get(Ty, APFloat((float)V)); - else if (Ty==Type::DoubleTy) - return ConstantFP::get(Ty, APFloat(V)); - else - assert(0); + if (errno != 0) { + errno = 0; + return 0; } - errno = 0; - return 0; + + if (Ty == Type::FloatTy) + return ConstantFP::get(APFloat((float)V)); + if (Ty == Type::DoubleTy) + return ConstantFP::get(APFloat(V)); + assert(0 && "Can only constant fold float/double"); + return 0; // dummy return to suppress warning } /// ConstantFoldCall - Attempt to constant fold a call to the specified function @@ -533,6 +707,8 @@ llvm::ConstantFoldCall(Function *F, return ConstantFoldFP(cos, V, Ty); else if (Len == 4 && !strcmp(Str, "cosh")) return ConstantFoldFP(cosh, V, Ty); + else if (Len == 4 && !strcmp(Str, "cosf")) + return ConstantFoldFP(cos, V, Ty); break; case 'e': if (Len == 3 && !strcmp(Str, "exp")) @@ -554,8 +730,7 @@ llvm::ConstantFoldCall(Function *F, if (V >= -0.0) return ConstantFoldFP(sqrt, V, Ty); else // Undefined - return ConstantFP::get(Ty, Ty==Type::FloatTy ? APFloat(0.0f) : - APFloat(0.0)); + return Constant::getNullValue(Ty); } break; case 's': @@ -567,6 +742,8 @@ llvm::ConstantFoldCall(Function *F, return ConstantFoldFP(sqrt, V, Ty); else if (Len == 5 && !strcmp(Str, "sqrtf") && V >= 0) return ConstantFoldFP(sqrt, V, Ty); + else if (Len == 4 && !strcmp(Str, "sinf")) + return ConstantFoldFP(sin, V, Ty); break; case 't': if (Len == 3 && !strcmp(Str, "tan")) @@ -608,11 +785,11 @@ llvm::ConstantFoldCall(Function *F, } } else if (ConstantInt *Op2C = dyn_cast(Operands[1])) { if (!strcmp(Str, "llvm.powi.f32")) { - return ConstantFP::get(Ty, APFloat((float)std::pow((float)Op1V, - (int)Op2C->getZExtValue()))); + return ConstantFP::get(APFloat((float)std::pow((float)Op1V, + (int)Op2C->getZExtValue()))); } else if (!strcmp(Str, "llvm.powi.f64")) { - return ConstantFP::get(Ty, APFloat((double)std::pow((double)Op1V, - (int)Op2C->getZExtValue()))); + return ConstantFP::get(APFloat((double)std::pow((double)Op1V, + (int)Op2C->getZExtValue()))); } } }