rjmccall added inline comments.
================
Comment at: cfe/trunk/lib/CodeGen/CGExpr.cpp:4268
+ DestTy.getAddressSpace(), ConvertType(DestTy));
+ return MakeNaturalAlignPointeeAddrLValue(V, DestTy);
+ }
----------------
romanovvlad wrote:
> Hi,
>
> It seems this code doesn't work correctly(repro at the end). TBAA information
> is lost here because MakeNaturalAlignPointeeAddrLValue constructs LValue with
> alignment of poinee type but TBAA info is taken from pointer itself what is
> strange enough. As a result, for example, memcpy with wrong size is generated
> for copy constructors.
>
> Repro:
>
> ```
> class P {
> public:
> P(const P &Rhs) = default;
>
> long a;
> long b;
> };
>
> __kernel void foo(__global P* GPtr) {
> P Val = GPtr[0];
> }
> ```
>
> As a solution the line could be replaced with the following:
> ```
> return MakeAddrLValue(Address(V, LV.getAddress().getAlignment()),
> E->getType(), LV.getBaseInfo(),
> CGM.getTBAAInfoForSubobject(LV,
> E->getType()));
> ```
> To take all the information from the original pointer.
>
> What do you think about solution?
>
Oh, yes, this should absolutely not be using
`MakeNaturalAlignPointerAddrLValue`; it should be preserving all of the extra
information from the original l-value, as you say.
I think TBAA information is independent of address-space qualification and can
just be taken from the original LV directly instead of using
`getTBAAInfoForSubobject`.
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D53764/new/
https://reviews.llvm.org/D53764
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