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refactor some code, no functionality change.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44849 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-12-11 05:55:02 +00:00
parent 22f07ffd27
commit 2b0f806c88
1 changed files with 96 additions and 94 deletions
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190
lib/VMCore/ConstantFold.cpp
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@ -138,6 +138,101 @@ foldConstantCastPair(
Type::Int64Ty);
}
static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
const Type *SrcTy = V->getType();
if (SrcTy == DestTy)
return V; // no-op cast
// Check to see if we are casting a pointer to an aggregate to a pointer to
// the first element. If so, return the appropriate GEP instruction.
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy)) {
SmallVector<Value*, 8> IdxList;
IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
const Type *ElTy = PTy->getElementType();
while (ElTy != DPTy->getElementType()) {
if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
if (STy->getNumElements() == 0) break;
ElTy = STy->getElementType(0);
IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
} else if (const SequentialType *STy = dyn_cast<SequentialType>(ElTy)) {
if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
ElTy = STy->getElementType();
IdxList.push_back(IdxList[0]);
} else {
break;
}
}
if (ElTy == DPTy->getElementType())
return ConstantExpr::getGetElementPtr(V, &IdxList[0], IdxList.size());
}
// Handle casts from one vector constant to another. We know that the src
// and dest type have the same size (otherwise its an illegal cast).
if (const VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
"Not cast between same sized vectors!");
// First, check for null. Undef is already handled.
if (isa<ConstantAggregateZero>(V))
return Constant::getNullValue(DestTy);
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 = CV->getNumOperands(); i != e; ++i) {
if (!isa<ConstantInt>(CV->getOperand(i)) &&
!isa<ConstantFP>(CV->getOperand(i))) {
AllSimpleConstants = false;
break;
}
}
// If all of the elements are simple constants, we can fold this.
if (AllSimpleConstants)
return CastConstantVector(const_cast<ConstantVector*>(CV), DestPTy);
}
}
}
// Finally, implement bitcast folding now. The code below doesn't handle
// bitcast right.
if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
return ConstantPointerNull::get(cast<PointerType>(DestTy));
// Handle integral constant input.
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (DestTy->isInteger())
// Integral -> Integral. This is a no-op because the bit widths must
// be the same. Consequently, we just fold to V.
return V;
if (DestTy->isFloatingPoint()) {
assert((DestTy == Type::DoubleTy || DestTy == Type::FloatTy) &&
"Unknown FP type!");
return ConstantFP::get(DestTy, APFloat(CI->getValue()));
}
// Otherwise, can't fold this (vector?)
return 0;
}
// Handle ConstantFP input.
if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
// FP -> Integral.
if (DestTy == Type::Int32Ty) {
return ConstantInt::get(FP->getValueAPF().convertToAPInt());
} else {
assert(DestTy == Type::Int64Ty && "only support f32/f64 for now!");
return ConstantInt::get(FP->getValueAPF().convertToAPInt());
}
}
return 0;
}
Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
const Type *DestTy) {
const Type *SrcTy = V->getType();
@ -268,100 +363,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
}
return 0;
case Instruction::BitCast:
if (SrcTy == DestTy)
return (Constant*)V; // no-op cast
// Check to see if we are casting a pointer to an aggregate to a pointer to
// the first element. If so, return the appropriate GEP instruction.
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy)) {
SmallVector<Value*, 8> IdxList;
IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
const Type *ElTy = PTy->getElementType();
while (ElTy != DPTy->getElementType()) {
if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
if (STy->getNumElements() == 0) break;
ElTy = STy->getElementType(0);
IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
} else if (const SequentialType *STy =
dyn_cast<SequentialType>(ElTy)) {
if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
ElTy = STy->getElementType();
IdxList.push_back(IdxList[0]);
} else {
break;
}
}
if (ElTy == DPTy->getElementType())
return ConstantExpr::getGetElementPtr(
const_cast<Constant*>(V), &IdxList[0], IdxList.size());
}
// Handle casts from one vector constant to another. We know that the src
// and dest type have the same size (otherwise its an illegal cast).
if (const VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
"Not cast between same sized vectors!");
// First, check for null and undef
if (isa<ConstantAggregateZero>(V))
return Constant::getNullValue(DestTy);
if (isa<UndefValue>(V))
return UndefValue::get(DestTy);
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 = CV->getNumOperands(); i != e; ++i) {
if (!isa<ConstantInt>(CV->getOperand(i)) &&
!isa<ConstantFP>(CV->getOperand(i))) {
AllSimpleConstants = false;
break;
}
}
// If all of the elements are simple constants, we can fold this.
if (AllSimpleConstants)
return CastConstantVector(const_cast<ConstantVector*>(CV), DestPTy);
}
}
}
// Finally, implement bitcast folding now. The code below doesn't handle
// bitcast right.
if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
return ConstantPointerNull::get(cast<PointerType>(DestTy));
// Handle integral constant input.
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (DestTy->isInteger())
// 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()) {
assert((DestTy == Type::DoubleTy || DestTy == Type::FloatTy) &&
"Unknown FP type!");
return ConstantFP::get(DestTy, APFloat(CI->getValue()));
}
// Otherwise, can't fold this (vector?)
return 0;
}
// Handle ConstantFP input.
if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
// FP -> Integral.
if (DestTy == Type::Int32Ty) {
return ConstantInt::get(FP->getValueAPF().convertToAPInt());
} else {
assert(DestTy == Type::Int64Ty && "only support f32/f64 for now!");
return ConstantInt::get(FP->getValueAPF().convertToAPInt());
}
}
return 0;
return FoldBitCast(const_cast<Constant*>(V), DestTy);
default:
assert(!"Invalid CE CastInst opcode");
break;