[llvm] [AMDGPU] Prefer lower total register usage in regions with spilling (PR #71882)

[Jeffrey Byrnes via llvm-commits]

jrbyrnes wrote:

> @jrbyrnes , since SGPR spills to VGPR, the value of 32 makes sense, as well as 64 for wave64. But why the max value of ExcessVGPRWeight is 2048?

I set that to the upper limit to avoid overflow concerns, and I couldn't imagine any reason why we would want to set it any higher than that. But, in the latest iteration, I have removed the option altogether.

https://github.com/llvm/llvm-project/pull/71882