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

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D47831#1123973, @kparzysz wrote:

> Is is possible to end up with the abs patterns after simplifying/legalizing an existing DAG, without having them exposed in the IR earlier on?


I can't rule it out completely, but that seems very unlikely given that we have a generic ABS node. Some set of smaller DAG transforms would have to unknowingly produce the shift+xor+add/sub instructions independently without realizing it has created the larger ABS node?


Repository:
  rL LLVM

https://reviews.llvm.org/D47831