[PATCH] D49262: [DAGCombiner] Call SimplifyDemandedVectorElts from EXTRACT_VECTOR_ELT

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

Hmm ...  The SystemZ tests seem to be getting strictly worse.  Before, we have in f3:

  vaf     %v0, %v24, %v26
  vlgvh   %r0, %v0, 6
  vlgvh   %r2, %v28, 3
  ar      %r2, %r0

and after the patch you're testing for:

  vaf %v0, %v24, %v26
  vrepf %v0, %v0, 3
  vlgvh %r0, %v0, 2
  vlgvh %r2, %v28, 3
  ar %r2, %r0

(And similar for f4.)

Given that the point of this test to ensure that there is no superfluous vrep, this seems a clear regression.  Can you check what's going on here?


Repository:
  rL LLVM

https://reviews.llvm.org/D49262