[llvm] [LV] Limits the splat operations be hoisted must not be defined by a recipe. (PR #117138)

[Mel Chen via llvm-commits]

Mel-Chen wrote:

> I think it should be possible to organize the declarations in a better way to enable this (with the main other benefit being that it also reduces the size of VPlan.h): #124104

Thanks, #124104 help me a lot! I j already rebased this patch on that.:)
But I just saw https://github.com/llvm/llvm-project/pull/124644, do we still need to use VPDominatorTree?
In my opinion, the explicit splat is the best approach to resolve this issue.

https://github.com/llvm/llvm-project/pull/117138