[clang] [llvm] [SROA] Vector promote some memsets (PR #133301)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

Missing PR description. The tests also don't make any sense to me, seeing as they compile down to a constant, unused insertelement.

https://github.com/llvm/llvm-project/pull/133301