[PATCH] D77105: [GlobalISel] Implement identity transforms for x op x -> x

[Jessica Paquette via Phabricator via llvm-commits]

paquette added a comment.

@qcolombet I'm not entirely sure, but patterns like this do hit a couple times in CTMark (but not very frequently, just once or twice.)

I'm surprised that they aren't entirely handled by InstCombine, but I'm guessing that they tend to appear in codegen at least once in a while considering they all exist in the DAGCombiner as well.

My best guess is that more complex combines simplify things enough that these patterns become obvious and thus can be eliminated.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77105/new/

https://reviews.llvm.org/D77105