[PATCH] D42479: DAGCombiner: Combine SDIV with non-splat vector pow2 divisor

[Zvi Rackover via Phabricator via llvm-commits]

zvi added a comment.

In https://reviews.llvm.org/D42479#1011497, @RKSimon wrote:

> I still think it'd be better if you treated splat vectors as a vector instead of a scalar - your change to matchUnaryPredicate means that we're accepting UNDEF elements where we weren't before, which for DIV/REM opcodes is supposed to be a big no-no.


I think that at the point this combine runs there should not be any undef elements because there is an earlier combine that handles division by undef (or vector with any undef elements)., see SelectionDAG::isUndef.


Repository:
  rL LLVM

https://reviews.llvm.org/D42479