[clang] [llvm] [Clang][LLVM] Implement single-single vectors MOP4{A/S} (PR #127797)

[via llvm-commits]

https://github.com/CarolineConcatto commented:

Thank you Virginia,
I left some comments. I hope it makes sense, if not let me know.

https://github.com/llvm/llvm-project/pull/127797