[llvm] [ReachingDefAnalysis] Extend the analysis to stack objects. (PR #118097)

[Michael Maitland via llvm-commits]

https://github.com/michaelmaitland commented:

Could you please precommit the rename of PhysReg -> Reg as its own NFC commit so it is easier to review what changes are required to extend the analysis to stack object.

https://github.com/llvm/llvm-project/pull/118097