[PATCH] D50091: [SelectionDAG] try harder to convert funnel shift to rotate

[Sanjay Patel via Phabricator via llvm-commits]

spatel planned changes to this revision.
spatel added a comment.

There's a subtle bug in the existing code. The conversion we're using to avoid the select for rotates (1st 2 args are the same, X == Y) only works for pow-of-2 bitwidths:
https://rise4fun.com/Alive/8Xp
I can't tell yet if that bug was visible in the codegen for the existing non-pow-of-2 tests, and we just overlooked it.

I'll fix that and update this after.


https://reviews.llvm.org/D50091