[llvm] [LV] Vectorize predicated loop-invariant loads via masked load + broadcast (PR #200361)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

Please split off `cseUniformMemoryReads` to a separate patch + tests. It should be testable independently, if the restriction for masked loads has been removed. If this cannot be included in the existing `cse` logic, please include details in the PR description

please also try to make sure all code paths are covered by tests

https://github.com/llvm/llvm-project/pull/200361