[PATCH] D81583: Update SystemZ ABI to handle C++20 [[no_unique_address]] attribute

[Ulrich Weigand via Phabricator via cfe-commits]

uweigand added a comment.

In D81583#2138127 <https://reviews.llvm.org/D81583#2138127>, @qiucf wrote:

> Thanks for this patch!
>
> If I understand correctly, only `isEmptyRecord`/`isEmptyField` and places checking any field is zero bit-width may need change for this? Since `isSingleElementStruct` and `isHomogeneousAggregate` just use them to skip empty fields in aggregate. I didn't see direct checking for empty fields on PowerPC. So all change needed on PPC seems to be generic. By enabling `AllowNoUniqueAddr` in these methods, case in https://lists.llvm.org/pipermail/llvm-dev/2020-July/143141.html can be correctly recognized as homogeneous aggregate.


I agree that probably the only required change is to set the `AllowNoUniqueAddr` parameter to true in those methods.  Given the discussion with @efriedma above, that may actually happen automatically if we remove the parameter (or default it to true).

In any case, I guess it would still be good to also have test cases for this aspect of the ABI on Power ...


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