[llvm] [AMDGPU][NewInsertWaitcnts] Boilerplate for the new wait insertion pass (PR #226335)

[Vasileios Porpodas via llvm-commits]

vporpo wrote:

> Also, please add a bit more content to the commit description explaining how we are co-developing it and how development will proceed. I think this is a good overview:
> 
> First milestone is getting conservatively correct waitcnts (maybe only for a subset of targets).
> Over the next few months, iteratively improve the implementation:
> We refine the architecture and may rewrite/redesign some parts of this until we are satisfied with the implementation.
> We will also continue progressing towards full parity with the old pass at the same time, addressing remaining targets/edge cases one by one.
> Permanently switch to the new pass.

These are great points to discuss, either here or on discourse, but I am not so sure they belong to the commit message. The commit message is more about what the patch does, not so much about the long term development/deployment plan etc.

https://github.com/llvm/llvm-project/pull/226335