Make sure we do not emit index computations with NSW flags so that we dont get an undef value if the GEP overflows
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160589
91177308-0d34-0410-b5e6-
96231b3b80d8
/// EmitGEPOffset - Given a getelementptr instruction/constantexpr, emit the
/// code necessary to compute the offset from the base pointer (without adding
/// in the base pointer). Return the result as a signed integer of intptr size.
/// EmitGEPOffset - Given a getelementptr instruction/constantexpr, emit the
/// code necessary to compute the offset from the base pointer (without adding
/// in the base pointer). Return the result as a signed integer of intptr size.
+/// When NoAssumptions is true, no assumptions about index computation not
+/// overflowing is made.
template<typename IRBuilderTy>
template<typename IRBuilderTy>
-Value *EmitGEPOffset(IRBuilderTy *Builder, const TargetData &TD, User *GEP) {
+Value *EmitGEPOffset(IRBuilderTy *Builder, const TargetData &TD, User *GEP,
+ bool NoAssumptions = false) {
gep_type_iterator GTI = gep_type_begin(GEP);
Type *IntPtrTy = TD.getIntPtrType(GEP->getContext());
Value *Result = Constant::getNullValue(IntPtrTy);
// If the GEP is inbounds, we know that none of the addressing operations will
// overflow in an unsigned sense.
gep_type_iterator GTI = gep_type_begin(GEP);
Type *IntPtrTy = TD.getIntPtrType(GEP->getContext());
Value *Result = Constant::getNullValue(IntPtrTy);
// If the GEP is inbounds, we know that none of the addressing operations will
// overflow in an unsigned sense.
- bool isInBounds = cast<GEPOperator>(GEP)->isInBounds();
+ bool isInBounds = cast<GEPOperator>(GEP)->isInBounds() && !NoAssumptions;
// Build a mask for high order bits.
unsigned IntPtrWidth = TD.getPointerSizeInBits();
// Build a mask for high order bits.
unsigned IntPtrWidth = TD.getPointerSizeInBits();
if (!bothKnown(PtrData))
return unknown();
if (!bothKnown(PtrData))
return unknown();
- Value *Offset = EmitGEPOffset(&Builder, *TD, &GEP);
+ Value *Offset = EmitGEPOffset(&Builder, *TD, &GEP, /*NoAssumptions=*/true);
Offset = Builder.CreateAdd(PtrData.second, Offset);
return std::make_pair(PtrData.first, Offset);
}
Offset = Builder.CreateAdd(PtrData.second, Offset);
return std::make_pair(PtrData.first, Offset);
}
%3 = load i8* %2, align 4
ret void
}
%3 = load i8* %2, align 4
ret void
}
+
+; CHECK: @f12
+define i64 @f12(i64 %x, i64 %y) nounwind {
+ %1 = tail call i8* @calloc(i64 1, i64 %x)
+; CHECK: mul i64 %y, 8
+ %2 = bitcast i8* %1 to i64*
+ %3 = getelementptr inbounds i64* %2, i64 %y
+ %4 = load i64* %3, align 8
+ ret i64 %4
+}