[clang] [AMDGPU] Add an option to disable unsafe uses of atomic xor (PR #69229)

[Matt Arsenault via cfe-commits]

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

I am opposed to adding any additional attributes for this. I very much want to remove the current unsafe-fp-atomics attribute. It's broken in the presence of inlining as it is, and at some point acquired too many meanings. There's also should be no reason to have separate FP and integer controls, there's nothing fundamental about the type here.

What we really need to do is have instruction level metadata annotations, separating the FP restrictions and the communication restrictions (which may or may not be isomorphic to a different scope). I have an incomplete patch where I was working towards this 


https://github.com/llvm/llvm-project/pull/69229