[llvm] [InstCombine] Resolve TODO: Remove one-time check if other logic operand (Y) is constant (PR #77973)

[via llvm-commits]

AtariDreams wrote:

> You have a commit to precommit tests, but the second commit doesn't touch any of the tests?
> 
> Also the precommit commit will need to be its own PR otherwise it'll get squashed when merging

I thought squashed while merging is what we wanted? 

https://github.com/llvm/llvm-project/pull/77973