[llvm] [MachineCombiner] Don't ignore PHI depths (PR #82025)

[Anton Sidorenko via llvm-commits]

asi-sc wrote:

> This means that Root currenty has that depth included in it, but NewRoot ignores it

That sounds completely wrong. 

> This patch simply removes that check for PHIs so that they are also counted.

What about loops? Have you had a chance to check how PHIs will be calculated for them?

https://github.com/llvm/llvm-project/pull/82025