[PATCH] D156778: [SelectionDAG] Improve `isKnownToBeAPowerOfTwo`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


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Comment at: llvm/test/CodeGen/X86/known-pow2.ll:625
 ; CHECK-NEXT:    pcmpeqd %xmm1, %xmm0
+; CHECK-NEXT:    pxor %xmm2, %xmm0
 ; CHECK-NEXT:    retq
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RKSimon wrote:
> Any luck in triaging this?
I think for vecs (on X86) doing `X & Y != 0` is just not preferable to `X & Y == Y`.
I fixed this up in D157014 and changed the rest of the `vselect` tests to use `ne` so we can properly see the change.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D156778/new/

https://reviews.llvm.org/D156778