[llvm] [SLP] Initial vectorization of non-power-of-2 ops. (PR #77790)

[Florian Hahn via llvm-commits]

fhahn wrote:

@dtcxzyw thanks for the reproducer, the issue was that in some cases on X86, MinVF wasn't a power-of-2. Fixed by using the stored type to compute the VF passed to `getStoreMinimumVF`

https://github.com/llvm/llvm-project/pull/77790