[PATCH] D151750: [DAGCombine] `select_cc seteq X, 0, 0, cttz_zero_undef(X) -> and(cttz(X), sizeof(X) - 1)`

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

What if the target doesn't natively support CTLZ/CTTZ and only has CTLZ_ZERO_UNDEF/CTTZ_ZERO_UNDEF will end up with a select followed by the AND? What if the target doesn't support CTTZ/CTLZ at all?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D151750/new/

https://reviews.llvm.org/D151750