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For PR1205: 

Implement constant folding via APInt instead of uint64_t.

llvm-svn: 34660
This commit is contained in:
Reid Spencer 2007-02-27 06:23:51 +00:00
parent db2049fb8e
commit 81658a8aca
1 changed files with 135 additions and 102 deletions
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237
llvm/lib/VMCore/ConstantFold.cpp
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@ -1,4 +1,4 @@
//===- ConstantFolding.cpp - LLVM constant folder -------------------------===//
//===- ConstantFold.cpp - LLVM constant folder ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
@ -8,7 +8,7 @@
//===----------------------------------------------------------------------===//
//
// This file implements folding of constants for LLVM. This implements the
// (internal) ConstantFolding.h interface, which is used by the
// (internal) ConstantFold.h interface, which is used by the
// ConstantExpr::get* methods to automatically fold constants when possible.
//
// The current constant folding implementation is implemented in two pieces: the
@ -38,11 +38,11 @@ using namespace llvm;
/// CastConstantVector - Convert the specified ConstantVector node to the
/// specified vector type. At this point, we know that the elements of the
/// input packed constant are all simple integer or FP values.
static Constant *CastConstantVector(ConstantVector *CP,
static Constant *CastConstantVector(ConstantVector *CV,
const VectorType *DstTy) {
unsigned SrcNumElts = CP->getType()->getNumElements();
unsigned SrcNumElts = CV->getType()->getNumElements();
unsigned DstNumElts = DstTy->getNumElements();
const Type *SrcEltTy = CP->getType()->getElementType();
const Type *SrcEltTy = CV->getType()->getElementType();
const Type *DstEltTy = DstTy->getElementType();
// If both vectors have the same number of elements (thus, the elements
@ -56,7 +56,7 @@ static Constant *CastConstantVector(ConstantVector *CP,
(SrcEltTy->isFloatingPoint() && DstEltTy->isFloatingPoint())) {
for (unsigned i = 0; i != SrcNumElts; ++i)
Result.push_back(
ConstantExpr::getBitCast(CP->getOperand(i), DstEltTy));
ConstantExpr::getBitCast(CV->getOperand(i), DstEltTy));
return ConstantVector::get(Result);
}
@ -67,7 +67,7 @@ static Constant *CastConstantVector(ConstantVector *CP,
if (DstEltTy->getTypeID() == Type::DoubleTyID) {
for (unsigned i = 0; i != SrcNumElts; ++i) {
double V =
BitsToDouble(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
BitsToDouble(cast<ConstantInt>(CV->getOperand(i))->getZExtValue());
Result.push_back(ConstantFP::get(Type::DoubleTy, V));
}
return ConstantVector::get(Result);
@ -75,7 +75,7 @@ static Constant *CastConstantVector(ConstantVector *CP,
assert(DstEltTy == Type::FloatTy && "Unknown fp type!");
for (unsigned i = 0; i != SrcNumElts; ++i) {
float V =
BitsToFloat(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
BitsToFloat(cast<ConstantInt>(CV->getOperand(i))->getZExtValue());
Result.push_back(ConstantFP::get(Type::FloatTy, V));
}
return ConstantVector::get(Result);
@ -86,9 +86,10 @@ static Constant *CastConstantVector(ConstantVector *CP,
if (SrcEltTy->getTypeID() == Type::DoubleTyID) {
for (unsigned i = 0; i != SrcNumElts; ++i) {
uint64_t V =
DoubleToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
Constant *C = ConstantInt::get(Type::Int64Ty, V);
double V =
DoubleToBits(cast<ConstantFP>(CV->getOperand(i))->getValue());
Constant *C = ConstantInt::get(Type::Int64Ty,
APIntOps::RoundDoubleToAPInt(V));
Result.push_back(ConstantExpr::getBitCast(C, DstEltTy ));
}
return ConstantVector::get(Result);
@ -96,7 +97,7 @@ static Constant *CastConstantVector(ConstantVector *CP,
assert(SrcEltTy->getTypeID() == Type::FloatTyID);
for (unsigned i = 0; i != SrcNumElts; ++i) {
uint32_t V = FloatToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
uint32_t V = FloatToBits(cast<ConstantFP>(CV->getOperand(i))->getValue());
Constant *C = ConstantInt::get(Type::Int32Ty, V);
Result.push_back(ConstantExpr::getBitCast(C, DstEltTy));
}
@ -174,12 +175,26 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
return ConstantFP::get(DestTy, FPC->getValue());
return 0; // Can't fold.
case Instruction::FPToUI:
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V))
return ConstantInt::get(DestTy,(uint64_t) FPC->getValue());
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
APInt Val(APIntOps::RoundDoubleToAPInt(FPC->getValue()));
uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
if (Val.getBitWidth() > DestBitWidth)
Val.trunc(DestBitWidth);
else if (Val.getBitWidth() < DestBitWidth)
Val.zext(DestBitWidth);
return ConstantInt::get(DestTy, Val);
}
return 0; // Can't fold.
case Instruction::FPToSI:
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V))
return ConstantInt::get(DestTy,(int64_t) FPC->getValue());
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
APInt Val(APIntOps::RoundDoubleToAPInt(FPC->getValue()));
uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
if (Val.getBitWidth() > DestBitWidth)
Val.trunc(DestBitWidth);
else if (Val.getBitWidth() < DestBitWidth)
Val.sext(DestBitWidth);
return ConstantInt::get(DestTy, Val);
}
return 0; // Can't fold.
case Instruction::IntToPtr: //always treated as unsigned
if (V->isNullValue()) // Is it an integral null value?
@ -191,23 +206,37 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
return 0; // Other pointer types cannot be casted
case Instruction::UIToFP:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
return ConstantFP::get(DestTy, double(CI->getZExtValue()));
if (CI->getType()->getBitWidth() <= APInt::APINT_BITS_PER_WORD)
return ConstantFP::get(DestTy, CI->getValue().roundToDouble(false));
return 0;
case Instruction::SIToFP:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
return ConstantFP::get(DestTy, double(CI->getSExtValue()));
if (CI->getType()->getBitWidth() <= APInt::APINT_BITS_PER_WORD)
return ConstantFP::get(DestTy, CI->getValue().roundToDouble(true));
return 0;
case Instruction::ZExt:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
return ConstantInt::get(DestTy, CI->getZExtValue());
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
APInt Result(CI->getValue());
Result.zext(BitWidth);
return ConstantInt::get(DestTy, Result);
}
return 0;
case Instruction::SExt:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
return ConstantInt::get(DestTy, CI->getSExtValue());
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
APInt Result(CI->getValue());
Result.sext(BitWidth);
return ConstantInt::get(DestTy, Result);
}
return 0;
case Instruction::Trunc:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) // Can't trunc a bool
return ConstantInt::get(DestTy, CI->getZExtValue());
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
APInt Result(CI->getValue());
Result.trunc(BitWidth);
return ConstantInt::get(DestTy, Result);
}
return 0;
case Instruction::BitCast:
if (SrcTy == DestTy)
@ -252,14 +281,14 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
if (isa<UndefValue>(V))
return UndefValue::get(DestTy);
if (const ConstantVector *CP = dyn_cast<ConstantVector>(V)) {
if (const ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
// This is a cast from a ConstantVector of one type to a
// ConstantVector of another type. Check to see if all elements of
// the input are simple.
bool AllSimpleConstants = true;
for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
if (!isa<ConstantInt>(CP->getOperand(i)) &&
!isa<ConstantFP>(CP->getOperand(i))) {
for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i) {
if (!isa<ConstantInt>(CV->getOperand(i)) &&
!isa<ConstantFP>(CV->getOperand(i))) {
AllSimpleConstants = false;
break;
}
@ -267,7 +296,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
// If all of the elements are simple constants, we can fold this.
if (AllSimpleConstants)
return CastConstantVector(const_cast<ConstantVector*>(CP), DestPTy);
return CastConstantVector(const_cast<ConstantVector*>(CV), DestPTy);
}
}
}
@ -279,9 +308,10 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
// Handle integral constant input.
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
// Integral -> Integral, must be changing sign.
if (DestTy->isInteger())
return ConstantInt::get(DestTy, CI->getZExtValue());
// Integral -> Integral. This is a no-op because the bit widths must
// be the same. Consequently, we just fold to V.
return const_cast<Constant*>(V);
if (DestTy->isFloatingPoint()) {
if (DestTy == Type::FloatTy)
@ -350,7 +380,7 @@ Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
const Constant *Idx) {
const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
if (!CIdx) return 0;
uint64_t idxVal = CIdx->getZExtValue();
APInt idxVal = CIdx->getValue();
if (isa<UndefValue>(Val)) {
// Insertion of scalar constant into packed undef
// Optimize away insertion of undef
@ -364,7 +394,7 @@ Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
Ops.reserve(numOps);
for (unsigned i = 0; i < numOps; ++i) {
const Constant *Op =
(i == idxVal) ? Elt : UndefValue::get(Elt->getType());
(idxVal == i) ? Elt : UndefValue::get(Elt->getType());
Ops.push_back(const_cast<Constant*>(Op));
}
return ConstantVector::get(Ops);
@ -382,7 +412,7 @@ Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
Ops.reserve(numOps);
for (unsigned i = 0; i < numOps; ++i) {
const Constant *Op =
(i == idxVal) ? Elt : Constant::getNullValue(Elt->getType());
(idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
Ops.push_back(const_cast<Constant*>(Op));
}
return ConstantVector::get(Ops);
@ -393,7 +423,7 @@ Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
Ops.reserve(CVal->getNumOperands());
for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
const Constant *Op =
(i == idxVal) ? Elt : cast<Constant>(CVal->getOperand(i));
(idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
Ops.push_back(const_cast<Constant*>(Op));
}
return ConstantVector::get(Ops);
@ -482,19 +512,19 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
case Instruction::Mul:
if (C2->isNullValue()) return const_cast<Constant*>(C2); // X * 0 == 0
if (const ConstantInt *CI = dyn_cast<ConstantInt>(C2))
if (CI->getZExtValue() == 1)
if (CI->equalsInt(1))
return const_cast<Constant*>(C1); // X * 1 == X
break;
case Instruction::UDiv:
case Instruction::SDiv:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(C2))
if (CI->getZExtValue() == 1)
if (CI->equalsInt(1))
return const_cast<Constant*>(C1); // X / 1 == X
break;
case Instruction::URem:
case Instruction::SRem:
if (const ConstantInt *CI = dyn_cast<ConstantInt>(C2))
if (CI->getZExtValue() == 1)
if (CI->equalsInt(1))
return Constant::getNullValue(CI->getType()); // X % 1 == 0
break;
case Instruction::And:
@ -508,7 +538,8 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
// Functions are at least 4-byte aligned. If and'ing the address of a
// function with a constant < 4, fold it to zero.
if (const ConstantInt *CI = dyn_cast<ConstantInt>(C2))
if (CI->getZExtValue() < 4 && isa<Function>(CPR))
if (CI->getValue().ult(APInt(CI->getType()->getBitWidth(),4)) &&
isa<Function>(CPR))
return Constant::getNullValue(CI->getType());
}
break;
@ -554,56 +585,66 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
// so look at directly computing the value.
if (const ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
uint64_t C1Val = CI1->getZExtValue();
uint64_t C2Val = CI2->getZExtValue();
using namespace APIntOps;
APInt C1V = CI1->getValue();
APInt C2V = CI2->getValue();
switch (Opcode) {
default:
break;
case Instruction::Add:
return ConstantInt::get(C1->getType(), C1Val + C2Val);
return ConstantInt::get(C1->getType(), C1V + C2V);
case Instruction::Sub:
return ConstantInt::get(C1->getType(), C1Val - C2Val);
return ConstantInt::get(C1->getType(), C1V - C2V);
case Instruction::Mul:
return ConstantInt::get(C1->getType(), C1Val * C2Val);
return ConstantInt::get(C1->getType(), C1V * C2V);
case Instruction::UDiv:
if (CI2->isNullValue()) // X / 0 -> can't fold
return 0;
return ConstantInt::get(C1->getType(), C1Val / C2Val);
if (CI2->isNullValue())
return 0; // X / 0 -> can't fold
return ConstantInt::get(C1->getType(), C1V.udiv(C2V));
case Instruction::SDiv:
if (CI2->isNullValue()) return 0; // X / 0 -> can't fold
if (CI2->isAllOnesValue() &&
(((CI1->getType()->getPrimitiveSizeInBits() == 64) &&
(CI1->getSExtValue() == INT64_MIN)) ||
(CI1->getSExtValue() == -CI1->getSExtValue() &&
CI1->getSExtValue())))
return 0; // MIN_INT / -1 -> overflow
return ConstantInt::get(C1->getType(),
CI1->getSExtValue() / CI2->getSExtValue());
case Instruction::URem:
if (C2->isNullValue()) return 0; // X / 0 -> can't fold
return ConstantInt::get(C1->getType(), C1Val % C2Val);
if (CI2->isNullValue())
return 0; // X / 0 -> can't fold
return ConstantInt::get(C1->getType(), C1V.sdiv(C2V));
if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
return 0; // MIN_INT / -1 -> overflow
return ConstantInt::get(C1->getType(), C1V.sdiv(C2V));
case Instruction::URem:
if (C2->isNullValue())
return 0; // X / 0 -> can't fold
return ConstantInt::get(C1->getType(), C1V.urem(C2V));
case Instruction::SRem:
if (CI2->isNullValue()) return 0; // X % 0 -> can't fold
if (CI2->isAllOnesValue() &&
(((CI1->getType()->getPrimitiveSizeInBits() == 64) &&
(CI1->getSExtValue() == INT64_MIN)) ||
(CI1->getSExtValue() == -CI1->getSExtValue())))
return 0; // MIN_INT % -1 -> overflow
return ConstantInt::get(C1->getType(),
CI1->getSExtValue() % CI2->getSExtValue());
if (CI2->isNullValue())
return 0; // X % 0 -> can't fold
if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
return 0; // MIN_INT % -1 -> overflow
return ConstantInt::get(C1->getType(), C1V.srem(C2V));
case Instruction::And:
return ConstantInt::get(C1->getType(), C1Val & C2Val);
return ConstantInt::get(C1->getType(), C1V & C2V);
case Instruction::Or:
return ConstantInt::get(C1->getType(), C1Val | C2Val);
return ConstantInt::get(C1->getType(), C1V | C2V);
case Instruction::Xor:
return ConstantInt::get(C1->getType(), C1Val ^ C2Val);
return ConstantInt::get(C1->getType(), C1V ^ C2V);
case Instruction::Shl:
return ConstantInt::get(C1->getType(), C1Val << C2Val);
if (uint32_t shiftAmt = C2V.getZExtValue())
if (shiftAmt <= C1V.getBitWidth())
return ConstantInt::get(C1->getType(), C1V.shl(shiftAmt));
else
return UndefValue::get(C1->getType()); // too big shift is undef
return const_cast<ConstantInt*>(CI1); // Zero shift is identity
case Instruction::LShr:
return ConstantInt::get(C1->getType(), C1Val >> C2Val);
if (uint32_t shiftAmt = C2V.getZExtValue())
if (shiftAmt <= C1V.getBitWidth())
return ConstantInt::get(C1->getType(), C1V.lshr(shiftAmt));
else
return UndefValue::get(C1->getType()); // too big shift is undef
return const_cast<ConstantInt*>(CI1); // Zero shift is identity
case Instruction::AShr:
return ConstantInt::get(C1->getType(),
CI1->getSExtValue() >> C2Val);
if (uint32_t shiftAmt = C2V.getZExtValue())
if (shiftAmt <= C1V.getBitWidth())
return ConstantInt::get(C1->getType(), C1V.ashr(shiftAmt));
else
return UndefValue::get(C1->getType()); // too big shift is undef
return const_cast<ConstantInt*>(CI1); // Zero shift is identity
}
}
} else if (const ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
@ -752,15 +793,15 @@ static FCmpInst::Predicate evaluateFCmpRelation(const Constant *V1,
Constant *C2 = const_cast<Constant*>(V2);
R = dyn_cast<ConstantInt>(
ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return FCmpInst::FCMP_OEQ;
R = dyn_cast<ConstantInt>(
ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return FCmpInst::FCMP_OLT;
R = dyn_cast<ConstantInt>(
ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return FCmpInst::FCMP_OGT;
// Nothing more we can do
@ -819,15 +860,15 @@ static ICmpInst::Predicate evaluateICmpRelation(const Constant *V1,
Constant *C2 = const_cast<Constant*>(V2);
ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return pred;
pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return pred;
pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
if (R && R->getZExtValue())
if (R && !R->isNullValue())
return pred;
// If we couldn't figure it out, bail.
@ -1045,28 +1086,20 @@ Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
}
if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
if (ICmpInst::isSignedPredicate(ICmpInst::Predicate(pred))) {
int64_t V1 = cast<ConstantInt>(C1)->getSExtValue();
int64_t V2 = cast<ConstantInt>(C2)->getSExtValue();
switch (pred) {
default: assert(0 && "Invalid ICmp Predicate"); return 0;
case ICmpInst::ICMP_SLT:return ConstantInt::get(Type::Int1Ty, V1 < V2);
case ICmpInst::ICMP_SGT:return ConstantInt::get(Type::Int1Ty, V1 > V2);
case ICmpInst::ICMP_SLE:return ConstantInt::get(Type::Int1Ty, V1 <= V2);
case ICmpInst::ICMP_SGE:return ConstantInt::get(Type::Int1Ty, V1 >= V2);
}
} else {
uint64_t V1 = cast<ConstantInt>(C1)->getZExtValue();
uint64_t V2 = cast<ConstantInt>(C2)->getZExtValue();
switch (pred) {
default: assert(0 && "Invalid ICmp Predicate"); return 0;
case ICmpInst::ICMP_EQ: return ConstantInt::get(Type::Int1Ty, V1 == V2);
case ICmpInst::ICMP_NE: return ConstantInt::get(Type::Int1Ty, V1 != V2);
case ICmpInst::ICMP_ULT:return ConstantInt::get(Type::Int1Ty, V1 < V2);
case ICmpInst::ICMP_UGT:return ConstantInt::get(Type::Int1Ty, V1 > V2);
case ICmpInst::ICMP_ULE:return ConstantInt::get(Type::Int1Ty, V1 <= V2);
case ICmpInst::ICMP_UGE:return ConstantInt::get(Type::Int1Ty, V1 >= V2);
}
APInt V1 = cast<ConstantInt>(C1)->getValue();
APInt V2 = cast<ConstantInt>(C2)->getValue();
switch (pred) {
default: assert(0 && "Invalid ICmp Predicate"); return 0;
case ICmpInst::ICMP_EQ: return ConstantInt::get(Type::Int1Ty, V1 == V2);
case ICmpInst::ICMP_NE: return ConstantInt::get(Type::Int1Ty, V1 != V2);
case ICmpInst::ICMP_SLT:return ConstantInt::get(Type::Int1Ty, V1.slt(V2));
case ICmpInst::ICMP_SGT:return ConstantInt::get(Type::Int1Ty, V1.sgt(V2));
case ICmpInst::ICMP_SLE:return ConstantInt::get(Type::Int1Ty, V1.sle(V2));
case ICmpInst::ICMP_SGE:return ConstantInt::get(Type::Int1Ty, V1.sge(V2));
case ICmpInst::ICMP_ULT:return ConstantInt::get(Type::Int1Ty, V1.ult(V2));
case ICmpInst::ICMP_UGT:return ConstantInt::get(Type::Int1Ty, V1.ugt(V2));
case ICmpInst::ICMP_ULE:return ConstantInt::get(Type::Int1Ty, V1.ule(V2));
case ICmpInst::ICMP_UGE:return ConstantInt::get(Type::Int1Ty, V1.uge(V2));
}
} else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
double C1Val = cast<ConstantFP>(C1)->getValue();