[clang] [llvm] [AMDGPU] Enable atomic optimizer for 64 bit divergent values (PR #96473)

[Vikram Hegde via cfe-commits]

vikramRH wrote:

closing this in favour of https://github.com/llvm/llvm-project/pull/96933 and https://github.com/llvm/llvm-project/pull/96934

https://github.com/llvm/llvm-project/pull/96473