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

[Vikram Hegde via cfe-commits]

vikramRH wrote:

Apologies for the commit spam here, graphite seems a good option now onwards. However all dependent patches have landed now, the diff here is now up to date.

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