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ConstantFolding: Tweak r173289, it should evaluate in the intptr type, not the index type. 

llvm-svn: 173293
This commit is contained in:
Benjamin Kramer 2013-01-23 21:21:24 +00:00
parent 5b4500b43a
commit 546bb56278
1 changed files with 15 additions and 18 deletions
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33
llvm/lib/Analysis/ConstantFolding.cpp
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@ -218,10 +218,10 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
/// 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 DataLayout &TD) {
APInt &Offset, const DataLayout &TD) {
// Trivial case, constant is the global.
if ((GV = dyn_cast<GlobalValue>(C))) {
Offset = 0;
Offset.clearAllBits();
return true;
}
@ -254,22 +254,17 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
if (!CI) return false; // Index isn't a simple constant?
if (CI->isZero()) continue; // Not adding anything.
// Evaluate offsets in the index type.
APInt APOffset(CI->getBitWidth(), Offset);
if (StructType *ST = dyn_cast<StructType>(*GTI)) {
// N = N + Offset
APOffset +=
APInt(CI->getBitWidth(),
TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()));
Offset +=
APInt(Offset.getBitWidth(),
TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()));
} else {
SequentialType *SQT = cast<SequentialType>(*GTI);
APOffset +=
APInt(CI->getBitWidth(),
TD.getTypeAllocSize(SQT->getElementType())*CI->getSExtValue());
Offset += APInt(Offset.getBitWidth(),
TD.getTypeAllocSize(SQT->getElementType()) *
CI->getSExtValue());
}
Offset = APOffset.getSExtValue();
}
return true;
}
@ -432,7 +427,7 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
if (BytesLoaded > 32 || BytesLoaded == 0) return 0;
GlobalValue *GVal;
int64_t Offset;
APInt Offset(TD.getPointerSizeInBits(), 0);
if (!IsConstantOffsetFromGlobal(C, GVal, Offset, TD))
return 0;
@ -443,14 +438,15 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
// If we're loading off the beginning of the global, some bytes may be valid,
// but we don't try to handle this.
if (Offset < 0) return 0;
if (Offset.isNegative()) return 0;
// If we're not accessing anything in this constant, the result is undefined.
if (uint64_t(Offset) >= TD.getTypeAllocSize(GV->getInitializer()->getType()))
if (Offset.getZExtValue() >=
TD.getTypeAllocSize(GV->getInitializer()->getType()))
return UndefValue::get(IntType);
unsigned char RawBytes[32] = {0};
if (!ReadDataFromGlobal(GV->getInitializer(), Offset, RawBytes,
if (!ReadDataFromGlobal(GV->getInitializer(), Offset.getZExtValue(), RawBytes,
BytesLoaded, TD))
return 0;
@ -574,7 +570,8 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
// constant. This happens frequently when iterating over a global array.
if (Opc == Instruction::Sub && TD) {
GlobalValue *GV1, *GV2;
int64_t Offs1, Offs2;
APInt Offs1(TD->getPointerSizeInBits(), 0),
Offs2(TD->getPointerSizeInBits(), 0);
if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD))
if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) &&