[clang] [clang-tools-extra] [llvm] [AMDGPU] GCNRegPressure printing pass for testing. (PR #70031)

[Jay Foad via cfe-commits]

https://github.com/jayfoad approved this pull request.

> Should we move on and submit this patch?

Yes!

> @jayfoad do you have concerns about live-through register set computation or others?

I personally have no interest in the live-through part. You could remove it from this patch, but I don't mind if others want to keep it.

> I believe fixing trackers should go to another PR.

Agreed.

https://github.com/llvm/llvm-project/pull/70031