[llvm-branch-commits] [llvm] release/18.x: Convert many LivePhysRegs uses to LiveRegUnits (PR #84118)

[Matt Arsenault via llvm-branch-commits]

arsenm wrote:

I don't think this should be rushed to the release branch. In particular patches should not deviate from the original main version in exceptional circumstances, but mostly this isn't fixing any known correctness issue 

https://github.com/llvm/llvm-project/pull/84118