6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-09-24 23:28:41 +00:00
Code Issues Projects Releases Wiki Activity

Remove the code which constant-folded ptrtoint(inttoptr(x)+c) to

Browse Source 
getelementptr. Despite only doing so in the case where x is a known
array object and c can be converted to an index within range, this
could still be invalid if c is actually the address of an object
allocated outside of LLVM. Also, SCEVExpander, the original motivation
for this code, has since been improved to avoid inttoptr+ptroint in
more cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96950 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2010-02-23 16:35:41 +00:00
parent c80a1f7721
commit b80a2a686f
2 changed files with 5 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
lib/Analysis/ConstantFolding.cpp
View File

@@ -783,44 +783,12 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
// 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<ConstantExpr>(Ops[0])) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
if (TD &&
TD->getPointerSizeInBits() <=
CE->getType()->getScalarSizeInBits()) {
if (CE->getOpcode() == Instruction::PtrToInt)
return FoldBitCast(CE->getOperand(0), DestTy, *TD);
// If there's a constant offset added to the integer value before
// it is casted back to a pointer, see if the expression can be
// converted into a GEP.
if (CE->getOpcode() == Instruction::Add)
if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(1)))
if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(0)))
if (R->getOpcode() == Instruction::PtrToInt)
if (GlobalVariable *GV =
dyn_cast<GlobalVariable>(R->getOperand(0))) {
const PointerType *GVTy = cast<PointerType>(GV->getType());
if (const ArrayType *AT =
dyn_cast<ArrayType>(GVTy->getElementType())) {
const Type *ElTy = AT->getElementType();
uint64_t AllocSize = TD->getTypeAllocSize(ElTy);
APInt PSA(L->getValue().getBitWidth(), AllocSize);
if (ElTy == cast<PointerType>(DestTy)->getElementType() &&
L->getValue().urem(PSA) == 0) {
APInt ElemIdx = L->getValue().udiv(PSA);
if (ElemIdx.ult(APInt(ElemIdx.getBitWidth(),
AT->getNumElements()))) {
Constant *Index[] = {
Constant::getNullValue(CE->getType()),
ConstantInt::get(ElTy->getContext(), ElemIdx)
};
return ConstantExpr::getGetElementPtr(GV, &Index[0], 2);
}
}
}
}
}
}
TD->getPointerSizeInBits() <= CE->getType()->getScalarSizeInBits() &&
CE->getOpcode() == Instruction::PtrToInt)
return FoldBitCast(CE->getOperand(0), DestTy, *TD);
return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::Trunc:
case Instruction::ZExt: