//===-- ConstantFolding.cpp - Analyze constant folding possibilities ------===// // // The LLVM Compiler Infrastructure // // 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. // //===----------------------------------------------------------------------===// #include "llvm/Analysis/ConstantFolding.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" #include "llvm/Instructions.h" #include "llvm/Intrinsics.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringMap.h" #include "llvm/Target/TargetData.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/MathExtras.h" #include #include using namespace llvm; //===----------------------------------------------------------------------===// // Constant Folding internal helper functions //===----------------------------------------------------------------------===// /// 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(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) 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 (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i, ++GTI) { ConstantInt *CI = dyn_cast(CE->getOperand(i)); if (!CI) return false; // Index isn't a simple constant? if (CI->getZExtValue() == 0) continue; // Not adding anything. if (const StructType *ST = dyn_cast(*GTI)) { // N = N + Offset Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()); } else { const SequentialType *SQT = cast(*GTI); Offset += TD.getABITypeSize(SQT->getElementType())*CI->getSExtValue(); } } return true; } return false; } /// 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); } } // TODO: Fold icmp setne/seteq as well. return 0; } /// 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 (!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; } 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); } } return 0; } /// 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. } // 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()); } } return 0; } //===----------------------------------------------------------------------===// // 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) { if (PHINode *PN = dyn_cast(I)) { if (PN->getNumIncomingValues() == 0) return Constant::getNullValue(PN->getType()); Constant *Result = dyn_cast(PN->getIncomingValue(0)); if (Result == 0) return 0; // Handle PHI nodes specially here... for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) if (PN->getIncomingValue(i) != Result && PN->getIncomingValue(i) != PN) return 0; // Not all the same incoming constants... // If we reach here, all incoming values are the same constant. return Result; } // 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))) Ops.push_back(Op); else return 0; // All operands not constant! if (const CmpInst *CI = dyn_cast(I)) return ConstantFoldCompareInstOperands(CI->getPredicate(), &Ops[0], Ops.size(), TD); else return ConstantFoldInstOperands(I->getOpcode(), I->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 /// attempting to fold instructions like loads and stores, which have no /// constant expression form. /// 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(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::Call: if (Function *F = dyn_cast(Ops[0])) if (canConstantFoldCallTo(F)) return ConstantFoldCall(F, Ops+1, NumOps-1); return 0; case Instruction::ICmp: case Instruction::FCmp: 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 // 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::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); // 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: 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) 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: 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 = 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*const * Ops, unsigned NumOps, 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 (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(Ops[0])) { if (TD && Ops[1]->isNullValue()) { 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 *C = ConstantExpr::getIntegerCast(CE0->getOperand(0), IntPtrTy, false); Constant *NewOps[] = { C, Constant::getNullValue(C->getType()) }; 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) { Constant *C = CE0->getOperand(0); Constant *NewOps[] = { C, Constant::getNullValue(C->getType()) }; // FIXME! return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD); } } 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 && Ops[1]->getOperand(0)->getType() == IntPtrTy) || (CE0->getOpcode() == Instruction::PtrToInt && CE0->getType() == IntPtrTy && CE0->getOperand(0)->getType() == Ops[1]->getOperand(0)->getType())) { Constant *NewOps[] = { CE0->getOperand(0), cast(Ops[1])->getOperand(0) }; return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD); } } } return ConstantExpr::getCompare(Predicate, Ops[0], Ops[1]); } /// 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(*I)) { ConstantInt *CU = cast(I.getOperand()); assert(CU->getZExtValue() < STy->getNumElements() && "Struct index out of range!"); unsigned El = (unsigned)CU->getZExtValue(); if (ConstantStruct *CS = dyn_cast(C)) { C = CS->getOperand(El); } else if (isa(C)) { C = Constant::getNullValue(STy->getElementType(El)); } else if (isa(C)) { C = UndefValue::get(STy->getElementType(El)); } else { return 0; } } else if (ConstantInt *CI = dyn_cast(I.getOperand())) { if (const ArrayType *ATy = dyn_cast(*I)) { if (CI->getZExtValue() >= ATy->getNumElements()) return 0; if (ConstantArray *CA = dyn_cast(C)) C = CA->getOperand(CI->getZExtValue()); else if (isa(C)) C = Constant::getNullValue(ATy->getElementType()); else if (isa(C)) C = UndefValue::get(ATy->getElementType()); else return 0; } else if (const VectorType *PTy = dyn_cast(*I)) { if (CI->getZExtValue() >= PTy->getNumElements()) return 0; if (ConstantVector *CP = dyn_cast(C)) C = CP->getOperand(CI->getZExtValue()); else if (isa(C)) C = Constant::getNullValue(PTy->getElementType()); else if (isa(C)) C = UndefValue::get(PTy->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(const Function *F) { switch (F->getIntrinsicID()) { case Intrinsic::sqrt: case Intrinsic::powi: case Intrinsic::bswap: case Intrinsic::ctpop: case Intrinsic::ctlz: case Intrinsic::cttz: return true; default: break; } const ValueName *NameVal = F->getValueName(); if (NameVal == 0) return false; const char *Str = NameVal->getKeyData(); unsigned Len = NameVal->getKeyLength(); // 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 (Str[0]) { default: return false; case 'a': if (Len == 4) return !strcmp(Str, "acos") || !strcmp(Str, "asin") || !strcmp(Str, "atan"); else if (Len == 5) return !strcmp(Str, "atan2"); return false; case 'c': if (Len == 3) return !strcmp(Str, "cos"); else if (Len == 4) return !strcmp(Str, "ceil") || !strcmp(Str, "cosf") || !strcmp(Str, "cosh"); return false; case 'e': if (Len == 3) return !strcmp(Str, "exp"); return false; case 'f': if (Len == 4) return !strcmp(Str, "fabs") || !strcmp(Str, "fmod"); else if (Len == 5) return !strcmp(Str, "floor"); return false; break; case 'l': if (Len == 3 && !strcmp(Str, "log")) return true; if (Len == 5 && !strcmp(Str, "log10")) return true; return false; case 'p': if (Len == 3 && !strcmp(Str, "pow")) return true; return false; case 's': if (Len == 3) return !strcmp(Str, "sin"); if (Len == 4) return !strcmp(Str, "sinh") || !strcmp(Str, "sqrt") || !strcmp(Str, "sinf"); if (Len == 5) return !strcmp(Str, "sqrtf"); return false; case 't': if (Len == 3 && !strcmp(Str, "tan")) return true; else if (Len == 4 && !strcmp(Str, "tanh")) return true; return false; } } static Constant *ConstantFoldFP(double (*NativeFP)(double), double V, const Type *Ty) { errno = 0; V = NativeFP(V); if (errno != 0) { errno = 0; return 0; } if (Ty == Type::FloatTy) return ConstantFP::get(Ty, APFloat((float)V)); if (Ty == Type::DoubleTy) return ConstantFP::get(Ty, APFloat(V)); assert(0 && "Can only constant fold float/double"); } static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), double V, double W, const Type *Ty) { errno = 0; V = NativeFP(V, W); if (errno != 0) { errno = 0; return 0; } if (Ty == Type::FloatTy) return ConstantFP::get(Ty, APFloat((float)V)); if (Ty == Type::DoubleTy) return ConstantFP::get(Ty, APFloat(V)); assert(0 && "Can only constant fold float/double"); } /// ConstantFoldCall - Attempt to constant fold a call to the specified function /// with the specified arguments, returning null if unsuccessful. Constant * llvm::ConstantFoldCall(Function *F, Constant* const* Operands, unsigned NumOperands) { const ValueName *NameVal = F->getValueName(); if (NameVal == 0) return 0; const char *Str = NameVal->getKeyData(); unsigned Len = NameVal->getKeyLength(); const Type *Ty = F->getReturnType(); if (NumOperands == 1) { if (ConstantFP *Op = dyn_cast(Operands[0])) { if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy) 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==Type::FloatTy ? (double)Op->getValueAPF().convertToFloat(): Op->getValueAPF().convertToDouble(); switch (Str[0]) { case 'a': if (Len == 4 && !strcmp(Str, "acos")) return ConstantFoldFP(acos, V, Ty); else if (Len == 4 && !strcmp(Str, "asin")) return ConstantFoldFP(asin, V, Ty); else if (Len == 4 && !strcmp(Str, "atan")) return ConstantFoldFP(atan, V, Ty); break; case 'c': if (Len == 4 && !strcmp(Str, "ceil")) return ConstantFoldFP(ceil, V, Ty); else if (Len == 3 && !strcmp(Str, "cos")) 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")) return ConstantFoldFP(exp, V, Ty); break; case 'f': if (Len == 4 && !strcmp(Str, "fabs")) return ConstantFoldFP(fabs, V, Ty); else if (Len == 5 && !strcmp(Str, "floor")) return ConstantFoldFP(floor, V, Ty); break; case 'l': if (Len == 3 && !strcmp(Str, "log") && V > 0) return ConstantFoldFP(log, V, Ty); else if (Len == 5 && !strcmp(Str, "log10") && V > 0) return ConstantFoldFP(log10, V, Ty); else if (!strcmp(Str, "llvm.sqrt.f32") || !strcmp(Str, "llvm.sqrt.f64")) { if (V >= -0.0) return ConstantFoldFP(sqrt, V, Ty); else // Undefined return ConstantFP::get(Ty, Ty==Type::FloatTy ? APFloat(0.0f) : APFloat(0.0)); } break; case 's': if (Len == 3 && !strcmp(Str, "sin")) return ConstantFoldFP(sin, V, Ty); else if (Len == 4 && !strcmp(Str, "sinh")) return ConstantFoldFP(sinh, V, Ty); else if (Len == 4 && !strcmp(Str, "sqrt") && V >= 0) 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")) return ConstantFoldFP(tan, V, Ty); else if (Len == 4 && !strcmp(Str, "tanh")) return ConstantFoldFP(tanh, V, Ty); break; default: break; } } else if (ConstantInt *Op = dyn_cast(Operands[0])) { if (Len > 11 && !memcmp(Str, "llvm.bswap", 10)) return ConstantInt::get(Op->getValue().byteSwap()); else if (Len > 11 && !memcmp(Str, "llvm.ctpop", 10)) return ConstantInt::get(Ty, Op->getValue().countPopulation()); else if (Len > 10 && !memcmp(Str, "llvm.cttz", 9)) return ConstantInt::get(Ty, Op->getValue().countTrailingZeros()); else if (Len > 10 && !memcmp(Str, "llvm.ctlz", 9)) return ConstantInt::get(Ty, Op->getValue().countLeadingZeros()); } } else if (NumOperands == 2) { if (ConstantFP *Op1 = dyn_cast(Operands[0])) { if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy) return 0; double Op1V = Ty==Type::FloatTy ? (double)Op1->getValueAPF().convertToFloat(): Op1->getValueAPF().convertToDouble(); if (ConstantFP *Op2 = dyn_cast(Operands[1])) { double Op2V = Ty==Type::FloatTy ? (double)Op2->getValueAPF().convertToFloat(): Op2->getValueAPF().convertToDouble(); if (Len == 3 && !strcmp(Str, "pow")) { return ConstantFoldBinaryFP(pow, Op1V, Op2V, Ty); } else if (Len == 4 && !strcmp(Str, "fmod")) { return ConstantFoldBinaryFP(fmod, Op1V, Op2V, Ty); } else if (Len == 5 && !strcmp(Str, "atan2")) { return ConstantFoldBinaryFP(atan2, Op1V, Op2V, Ty); } } 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()))); } else if (!strcmp(Str, "llvm.powi.f64")) { return ConstantFP::get(Ty, APFloat((double)std::pow((double)Op1V, (int)Op2C->getZExtValue()))); } } } } return 0; }