[PATCH] D66308: [InstCombine] Fold select with ctlz to cttz

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 created this revision.
xbolva00 added reviewers: spatel, nikic, lebedev.ri.
Herald added subscribers: llvm-commits, kristof.beyls, javed.absar.
Herald added a project: LLVM.

Handle pattern [0]:

int ctz(unsigned int a)
{

  int c = __clz(a & -a);
  return a ? 31 - c : c;

}

[0] https://community.arm.com/community-help/f/discussions/2114/count-trailing-zeros


Repository:
  rL LLVM

https://reviews.llvm.org/D66308

Files:
  lib/Transforms/InstCombine/InstCombineSelect.cpp
  test/Transforms/InstCombine/select-ctlz-to-cttz.ll

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