[llvm] AMDGPU: Fix temporal divergence introduced by machine-sink and performance regression introduced by D155343 (PR #67456)

[via llvm-commits]

petar-avramovic wrote:

Thanks for the review closing this pr for now. I pushed commits to keep them separate.
Please let me know if you have any suggestions how to handle temporal divergence issues, I can work on a patch for that.

https://github.com/llvm/llvm-project/pull/67456