[PATCH] D46493: [DagCombiner] Not all 'andn''s work with immediates.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D46493#1090008, @lebedev.ri wrote:

> In https://reviews.llvm.org/D46493#1089988, @spatel wrote:
>
> > LGTM
>
>
> Thank you for the review!
>
> > but I want to point out that the mca analysis may not be accurate for these sequences yet. We don't have the zero idiom (xor %eax, %eax) recognition yet ( https://bugs.llvm.org/show_bug.cgi?id=36671 ), so the stats for those cases are probably pessimistic.
>
> I defer to you on the question whether `icmp-opt.ll`, `selectcc-to-shiftand.ll ` changes are a regression (in which case they should be updated to use `hasAndNotCompare()` instead of `hasAndNot()`)


No - I think the test+set sequences are likely equal or better for most uarch, so those are improvements. They should also be less instruction bytes, so that's good too.


Repository:
  rL LLVM

https://reviews.llvm.org/D46493