[llvm] [NVPTX] Stop using 16-bit CAS instructions from PTX (PR #120220)

[Akshay Deodhar via llvm-commits]

akshayrdeodhar wrote:

This is the case the PR is trying to address- 8-bit cmpxchg done using a loop of 16-bit atom.cas: https://godbolt.org/z/8fTqs13Ed

On the flipside, this degrades codegen for 16-bit cmpxchg: https://godbolt.org/z/rMbfc33dz


https://github.com/llvm/llvm-project/pull/120220