[PATCH] D65360: [AArch64][GlobalISel] Eliminate redundant G_ZEXT when the source is implicitly zext-loaded

Sat Jul 27 20:29:31 PDT 2019

arsenm added a comment.

In D65360#1603526 <https://reviews.llvm.org/D65360#1603526>, @aemerson wrote:

> In D65360#1603454 <https://reviews.llvm.org/D65360#1603454>, @arsenm wrote:
>
> > Shouldn’t the combiner have already gotten his?
>
>
> It does catch these cases, but sometimes these patterns arise later after the combiner due to some other optimization or DCE. By then the combiner has already run so we don’t merge these into G_ZEXTLOAD.

I kind of think this is an issue of not running another combiner round, and the selector should do minimal work

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  https://reviews.llvm.org/D65360/new/

https://reviews.llvm.org/D65360