[PATCH] D47831: [DAGCombiner] Recognize more patterns for ABS

[Sanjay Patel via Phabricator via llvm-commits]

spatel added reviewers: craig.topper, RKSimon, john.brawn.
spatel added a comment.

The subtract version was noted in PR36036:
https://bugs.llvm.org/show_bug.cgi?id=36036

And as commented there, we're now canonicalizing in IR to the form with select:
https://reviews.llvm.org/D40984

And there were more IR improvements for abs() here:
https://reviews.llvm.org/D47041
https://reviews.llvm.org/D47076
https://reviews.llvm.org/D47631

...so can we add the IR canonicalization for the subtract version (solve PR36036) and be done with this? Ie, can we already remove the DAG combine for the half-implemented 'add' version because we're confident that IR is now always going to be in the canonical 'select' form? Is there some place in the DAG that creates abs() in a non-canonical form?


Repository:
  rL LLVM

https://reviews.llvm.org/D47831