[PATCH] D105659: [PowerPC][AIX] Support ByVals with greater alignment then pointer size

Thu Sep 23 09:04:58 PDT 2021

ZarkoCA added a comment.

In D105659#3018330 <https://reviews.llvm.org/D105659#3018330>, @cebowleratibm wrote:

> As we lift the backend fatal error we expose the risk of generating silently incompatible code with the XLC compiler on AIX.  I think a clang warning diagnostic is warranted for 16 byte aligned byval args where the struct is 16 byte aligned and does not contain a vector member.  I don't think this case is common so the diagnostic shouldn't be too verbose.
>
> I consider the insufficiently aligned address of the parameter an XLC bug and this change makes clang consistent with GCC on AIX, so I agree with the intention of the change.
>
> If you agree with the clang diagnostic, I think it's better to land that before committing this just so that we don't expose ourselves to emitting silently incompatible code.

The clang diagnostic is already committed in https://reviews.llvm.org/rG66225db98d832bec75ffb96298107c015b0035f0 but I should have updated the description for clarity.

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  https://reviews.llvm.org/D105659/new/

https://reviews.llvm.org/D105659