[PATCH] D114354: [DAG] SimplifyDemandedBits - simplify rotl/rotr to shl/srl

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

I don't understand the changes to the SystemZ test cases.   The new behavior seems to be simply wrong?

Note that the tests you change are specifically constructed to require bits from **both** arms of the rotate pattern, so they cannot be optimized to a simple shift - if this optimization does that in these cases, something seems to be wrong here.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114354/new/

https://reviews.llvm.org/D114354