[llvm] [AMDGPU] Improve selection of ballot.i64 intrinsic in wave32 mode in SelectionDAG. (PR #71556)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

Is this just about code quality? This probably isn't necessary if you consider the pipeline as a whole. I believe InstCombine is already reducing i64 ballot to i32 based on the subtarget's wave size 

https://github.com/llvm/llvm-project/pull/71556