[llvm] Late temporal divergence lowering for SDAG (PR #67033)

[Sameer Sahasrabuddhe via llvm-commits]

https://github.com/ssahasra commented:

I think the first line of the commit description should not mention machine sink. The issue was triggered by machine sink, but this change introduces a pass that works in general.

https://github.com/llvm/llvm-project/pull/67033