[llvm] [AMDGPU] Preserve old MSBs when handling SETREG (PR #191352)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> I really don't see the point of this, but it's harmless so I won't object if you really want to do it.

I've seen people complaining it is not universally recorded. I assume it is easier for the trap handler not to decode what has happened before the trap.

https://github.com/llvm/llvm-project/pull/191352