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When constant folding GEP expressions, keep the address space information of pointers.

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Together with Ran Chachick <ran.chachick@intel.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160954 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem
2012-07-30 07:25:20 +00:00
parent 818f609459
commit 97baaeaeb2
2 changed files with 29 additions and 3 deletions
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22
lib/Analysis/ConstantFolding.cpp
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@ -603,6 +603,22 @@ static Constant *CastGEPIndices(ArrayRef<Constant *> Ops,
return C;
}
/// Strip the pointer casts, but preserve the address space information.
static Constant* StripPtrCastKeepAS(Constant* Ptr) {
assert(Ptr->getType()->isPointerTy() && "Not a pointer type");
PointerType *OldPtrTy = cast<PointerType>(Ptr->getType());
Ptr = cast<Constant>(Ptr->stripPointerCasts());
PointerType *NewPtrTy = cast<PointerType>(Ptr->getType());
// Preserve the address space number of the pointer.
if (NewPtrTy->getAddressSpace() != OldPtrTy->getAddressSpace()) {
NewPtrTy = NewPtrTy->getElementType()->getPointerTo(
OldPtrTy->getAddressSpace());
Ptr = ConstantExpr::getBitCast(Ptr, NewPtrTy);
}
return Ptr;
}
/// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP
/// constant expression, do so.
static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
@ -639,13 +655,13 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
}
return 0;
}
unsigned BitWidth = TD->getTypeSizeInBits(IntPtrTy);
APInt Offset =
APInt(BitWidth, TD->getIndexedOffset(Ptr->getType(),
makeArrayRef((Value **)Ops.data() + 1,
Ops.size() - 1)));
Ptr = cast<Constant>(Ptr->stripPointerCasts());
Ptr = StripPtrCastKeepAS(Ptr);
// If this is a GEP of a GEP, fold it all into a single GEP.
while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
@ -664,7 +680,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
Ptr = cast<Constant>(GEP->getOperand(0));
Offset += APInt(BitWidth,
TD->getIndexedOffset(Ptr->getType(), NestedOps));
Ptr = cast<Constant>(Ptr->stripPointerCasts());
Ptr = StripPtrCastKeepAS(Ptr);
}
// If the base value for this address is a literal integer value, fold the