[llvm] [LoopVectorize] Don't scalarize predicated instruction with optsize (PR #129265)

[John Brawn via llvm-commits]

john-brawn-arm wrote:

> This only deals with scalarizing memory instructions, but other instructions could also be scalarized, e.g. via `collectInstsToScalarize` which would be missed a the moment?
> 
> A more general alternative that would make it easier to catch all instance would be to check the generated VPlans for replicating recipes/regions.

After looking into it it does look like this solves the problem in a nicer way. I'll update this PR to do that.


https://github.com/llvm/llvm-project/pull/129265