[llvm] [LoopVectorize][X86] Rewrite guaranteed-safe masked stores as load-blend-store] (PR #206654)

[Florian Hahn via llvm-commits]

fhahn wrote:

There are places that support this kind of speculative execution of stores (e.g. see `speculativelyExecuteBB`), I'd recommend taking a look at  the legality checks there. I think it roughly requires that it is a local object, that does not escape,  isWritableObject(Obj)  == true and must be known dereferenceable. 

I'd assume in the O3 pipeline, that `speculativelyExecuteBB` already takes care of such stores, if possible, but maybe the analysis can be improved further.

https://github.com/llvm/llvm-project/pull/206654