[llvm] [LV] Don't consider VPValues without underlying value as generating vectors (PR #150992)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

I think this makes sense to me, but I'm afraid I have to leave this up to @fhahn for a sanity-check.

https://github.com/llvm/llvm-project/pull/150992