[PATCH] D52318: [x86] avoid 256-bit andnp that requires insert/extract with AVX1 (PR37449)

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

For reference in case this comes up later: now that we're checking for the leading concat op, I think we could loosen the AVX1 constraint (do AVX512 flavors have this problem too?).

I tried to solve the problem generally in IR (if it occurs pre-legalization) with this instcombine patch:
https://reviews.llvm.org/rL342988


https://reviews.llvm.org/D52318