[libcxx-commits] [libcxx] [AMDGPU][MachineScheduler] Alternative way to control excess RP. (PR #68004)

[Austin Kerbow via libcxx-commits]

kerbowa wrote:

Continuing the discussion here as opposed to email.
> The UnclusteredHighRP is intended for those regions which have high RP after the scheduling is done.
> I think that we should run the UnclusteredHighRP only for regions which have excess Rp after the scheduling is done.
The original intent of unclustered scheduling was to increase occupancy in the kernel when it was possible to do so if we tried scheduling without mutations. The extra checks for excess RP and spilling were added later. There were concrete cases that motivated both of these changes.

That's not to say I don't approve of the new approach, any simplification of the current logic would be welcome, but I think it needs to be supported by performance numbers both on compute and graphics.

https://github.com/llvm/llvm-project/pull/68004