[PATCH] D122909: [InstCombine] limit icmp fold with sub if other sub user is a phi

Sat Apr 2 15:35:12 PDT 2022

spatel added a comment.

In D122909#3424861 <https://reviews.llvm.org/D122909#3424861>, @lebedev.ri wrote:

> In D122909#3424859 <https://reviews.llvm.org/D122909#3424859>, @spatel wrote:
>
>> In D122909#3422897 <https://reviews.llvm.org/D122909#3422897>, @lebedev.ri wrote:
>>
>>> It seems like something for a late undo pass to deal with.
>>
>> Agree, but the comments in https://github.com/llvm/llvm-project/issues/54558 suggested there wasn't a quick fix, and there are already one-use limitations here, so that's why I proposed a fast fix for the regression. Do you object to this change?
>
> No strong thoughts on this one. I just think it would be best to have a more general undo fold :)

Yes, I didn't look closely at the original example, but there was a comment about a cross-block limitation, so it might be a job for CGP.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D122909/new/

https://reviews.llvm.org/D122909