[llvm] [LV] Add initial support for vectorizing literal struct return values (PR #109833)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

> Just to make sure I am understanding correctly, this is specifically about VPReplicateRecipe and assumptions that it has a single def? Most transforms/analsyses should handle multi-defs ( as they have to deal with interleave recipes).

Those issues are specifically around supporting replication, which seemed to have quite a few assumptions around it being a single-def. I think the issues I've been hitting are while VPlan in general supports multiple defs, the code paths around calls/LLVM IR have previously always been single-def recipes. 


https://github.com/llvm/llvm-project/pull/109833