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

Roman Lebedev via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon May 7 10:46:00 PDT 2018


lebedev.ri added a comment.

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()`)


Repository:
  rL LLVM

https://reviews.llvm.org/D46493





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