[PATCH] D129650: [InstCombine] change conditions for transform of sub to xor

[Zaara Syeda via Phabricator via llvm-commits]

syzaara added a comment.

In D129650#3666095 <https://reviews.llvm.org/D129650#3666095>, @spatel wrote:

> In D129650#3666042 <https://reviews.llvm.org/D129650#3666042>, @syzaara wrote:
>
>> Note that we do not recognize the xor as a subtract of 8 SCEV expression. This prevents further simplifications on expressions using _sub_tmp4, because it is now represented as a symbol rather than a recognized SCEV operation.
Would it be possible to revert this until we teach SCEV how to handle the XOR?
>
> Please correct me if I've misunderstood: would **this** patch solve the problem that you are seeing? If we want to revert, that would be 79bb915fb60b <https://reviews.llvm.org/rG79bb915fb60b2cd220d89e3bb54f67abb8cdb7bd> ?

Oh sorry! Yes, I meant to post this comment for 79bb915fb60b <https://reviews.llvm.org/rG79bb915fb60b2cd220d89e3bb54f67abb8cdb7bd>. And I have double checked that this patch solves the issue. Looking forward to this being committed, if we are not reverting 79bb915fb60b <https://reviews.llvm.org/rG79bb915fb60b2cd220d89e3bb54f67abb8cdb7bd>. Thanks.


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