[PATCH] D134282: [CGP] Add generic TargetLowering::shouldAlignPointerArgs() implementation

[David Tenty via Phabricator via llvm-commits]

daltenty added a comment.

In D134282#4148884 <https://reviews.llvm.org/D134282#4148884>, @hubert.reinterpretcast wrote:

> In D134282#4148337 <https://reviews.llvm.org/D134282#4148337>, @efriedma wrote:
>
>> Is there any way we can make AIX targets more resilient handling this kind of alignment change?  If we have to, we can choose a point after which passes aren't allowed to increase the alignment of globals, and move this transform before that.  But I'd like to avoid that if possible.
>
> Not that I know of without negative side-effects. For example, if we access using a TOC entry for a label for the individual string, we would end up with more TOC entries which, in turn, can lead to TOC overflow.

I'm wondering if there is really a need to split these rodata csect by alignment the way we do for XCOFF. This behaviour seems to have it's origin in the ELF mergable string handling, and we don't have the same linker features.

I have a draft of such a change, that when combined with this patch, seems to resolve the issue we are seeing. I'll do some more evaluation offline to see if this is a viable resolution and report back.


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