[llvm] [MachineLICM] Correctly Apply Register Masks (PR #95746)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

I also observe that some predecessors are added to the IR after it goes through `llc` locally.
I wonder if this is caused by some pass changing the CFG without invalidating it, and the stale results affect MachineLICM and cause it to miscompile.

In other words, MachineLICM isn't at fault but some earlier pass that changes the CFG is.
Just a guess.

Can you also provide the unoptimized IR? You can get it through clang by disabling all LLVM passes (`-Xclang -disable-llvm-passes` or something?)

https://github.com/llvm/llvm-project/pull/95746