[ValueTracking] Match select abs pattern when there's an sext involved
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.
Differential Revision: https://reviews.llvm.org/D47631
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333927 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed