[PATCH] D130769: [RISCV] Combine and remove redundant ADD/SUB instructions

[Philip Reames via Phabricator via llvm-commits]

reames added a comment.

I'm not convinced as to the motivation of this patch.  Running the provided IR file through instcombine greatly simplifies it, and seems to remove the motivating pattern.  As such, either this is an overly reduced test (which is fine, but more motivation is needed in review description), or this is fixing a pass ordering problem in the middle end in the wrong place.

Can you explain why this is the right way to fix this problem?  At the moment, I'm unconvinced.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130769/new/

https://reviews.llvm.org/D130769