[clang] [llvm] [AMDGPU] Add initial support for VGPR as memory (PR #205435)

[Gheorghe-Teodor Bercea via cfe-commits]

doru1004 wrote:

> I think it would be good to add some PEI-directed tests to make sure we don't spill any of these registers if they end up in the callee-saved area.

Good catch! Fixed it and added a test.

https://github.com/llvm/llvm-project/pull/205435