[llvm] [AMDGPU][SIInsertWaitcnts][NFC] Introduce Counter class (PR #190271)

[Sameer Sahasrabuddhe via llvm-commits]

https://github.com/ssahasra requested changes to this pull request.

I have a concern with the piecemeal approach being taken to fix what ain't broke. There was a document that we reviewed internally, but even the solution in the proposal does not actually solve the problem it describes, instead only provides an intermediate state. Functions like `getUB()` and `setUB()` don't clean up anything since they do not represent true encapsulation. And `setUBNoLBClamp()` is a clear indicator that the design is far from done.

https://github.com/llvm/llvm-project/pull/190271