[PATCH] D85139: [GlobalISel] Don't transform FSUB(-0, X) -> FNEG(X) in GlobalISel.

Tue Aug 4 09:27:05 PDT 2020

arsenm added a comment.

In D85139#2193672 <https://reviews.llvm.org/D85139#2193672>, @cameron.mcinally wrote:

> In D85139#2193065 <https://reviews.llvm.org/D85139#2193065>, @arsenm wrote:
>
>> I think this leaves behind a redundant test_fneg/test_fneg_fmf case elsewhere
>
> You're probably right. Just took a look and I don't see anything obvious though. Did you have a particular set of tests in mind?
>
> I do see some tests that transform an illegal G_FNEG into an G_FSUB. I don't fully understand the motivation yet, but that's probably worth attention.

No, I mean you changed these cases using fsub in the irtranslator test, when there were already tests for fneg here already. LegalizerHelper still does have an incorrect expansion of fneg into fsub, but that's another story

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  https://reviews.llvm.org/D85139/new/

https://reviews.llvm.org/D85139