[PATCH] D51553: [DAGCombiner][x86] add transform/hook to load a scalar directly for use in a vector binop

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D51553#1251450, @efriedma wrote:

> For an insert into lane zero, it's never profitable to generate ymm/zmm instructions; we can just generate an xmm instruction and implicitly extend the result.


Right - that's what I was suggesting at the end of my last reply. So do we want to put this patch on hold to improve the undef/splat behaviors seen here first, or proceed here and file bugs for those problems?


https://reviews.llvm.org/D51553