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

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

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.


https://reviews.llvm.org/D51553