[llvm] [llvm][opt][Transforms] Preserve AMDGPU atomic metadata (PR #140314)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I wonder whether it would make sense to have a fallback behavior that allows preserving metadata if it is exactly the same on both instructions, even if it's unknown.

Do we have any metadata where preserving it in case of exact equality would be invalid?

https://github.com/llvm/llvm-project/pull/140314