[PATCH] D94641: [AArch64][GlobalISel] Use wzr/xzr for FP stores of zero

Thu Jan 14 16:29:01 PST 2021

aemerson added a comment.

In D94641#2498991 <https://reviews.llvm.org/D94641#2498991>, @paquette wrote:

> In D94641#2498944 <https://reviews.llvm.org/D94641#2498944>, @aemerson wrote:
>
>> It it possible to extend the existing combine in prelegalizer combiner to handle this too? Or will that cause us to still miss some cases?
>
> The problem with that combine is it looks for G_FCONSTANTS which are only used by stores, so as is, it would miss cases.
>
> I think that we could probably replace that combine with something similar to this though.

Right. I think it would be nice to keep these int/fp constant of 0 combines somewhat together. If you feel that it's not a net benefit to do that then I'm happy for this to go in as is.

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https://reviews.llvm.org/D94641