[llvm] [NVPTX] Add atom.add.noftz support, avoid CAS loops when noftz is available (PR #223569)

[Artem Belevich via llvm-commits]

https://github.com/Artem-B approved this pull request.

LGTM in general, if @chsigg is OK with the change.

https://github.com/llvm/llvm-project/pull/223569