[llvm] [MachineLICM] Give opportunity to analyze physregs for invariance. (PR #84779)

[Sander de Smalen via llvm-commits]

sdesmalen-arm wrote:

> This looks reasonable, but isn't it the same as `isIgnorableUse`? Or do you need this because you want hoisting but still want to prevent rematerialization?

Yes, the latter. We've added the implicit def/use of these registers to prevent rematerialization from occurring.

https://github.com/llvm/llvm-project/pull/84779