[PATCH] D146121: [DAG] Move lshr narrowing from visitANDLike to SimplifyDemandedBits (WIP)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon planned changes to this revision.
RKSimon added a comment.

Update - I'm going to investigate splitting this between the regular SimplifyDemandedBits DAG combines and some specific narrowing in X86ISelDAGToDAG.cpp + ISel - that way we have the best chance of making use of the extensive value tracking code we already have in SelectionDAG.

However, a lot of the DAG combines are already in place, we're just missing them due to poor combine ordering - so getting D127115 <https://reviews.llvm.org/D127115> completed once and for all will likely help us the most, so I'm looking at the remaining regressions there first, and then will revisit this for cleanup.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146121/new/

https://reviews.llvm.org/D146121