[PATCH] D42679: [DAGCombiner] When combining zero_extend of a truncate, only mask before extending for vectors.

[Artem Belevich via Phabricator via llvm-commits]

tra added a comment.

In https://reviews.llvm.org/D42679#1016635, @craig.topper wrote:

> @tra, did you figure out what was going on?


Some of it. Something weird is going on during lowering or i1 arguments in NVPTX and we end up with CopyToReg on a chain, but with no other uses. I've found references to what looks like a similar issue in PPC code (ANDIGlueBug <https://github.com/llvm-mirror/llvm/blob/master/lib/Target/PowerPC/PPCISelDAGToDAG.cpp#L86>), so it may not be a new issue. It certainly has nothing to do with your patch.

LGTM as far as NVPTX is concerned.


https://reviews.llvm.org/D42679