[PATCH] D47631: [ValueTracking] Match select abs pattern when there's an sext involved

[John Brawn via Phabricator via llvm-commits]

john.brawn created this revision.
john.brawn added reviewers: craig.topper, efriedma, hfinkel, Ka-Ka.
Herald added a reviewer: javed.absar.

When checking a select to see if it matches an abs, allow the true/false values to be a sign-extension of the comparison value instead of requiring that they're directly the comparison value, as all the comparison cares about is the sign of the value.

This fixes a regression due to r333702, where we were no longer generating ctlz due to isKnownNonNegative failing to match such a pattern.


Repository:
  rL LLVM

https://reviews.llvm.org/D47631

Files:
  lib/Analysis/ValueTracking.cpp
  test/Transforms/LoopIdiom/ARM/ctlz.ll
  test/Transforms/LoopIdiom/X86/ctlz.ll

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