[clang] [llvm] [AMDGPU] Change CF intrinsics lowering to reconverge on predecessors (PR #108596)

[Nicolai Hähnle via cfe-commits]

nhaehnle wrote:

Thank you for going into a bit more detail. It does seem like distinguishing between SGPR reloads and VGPR reloads would help.

Hmm, what about a case where we run out of VGPRs to spill SGPRs into? What do we actually do in that case today?

https://github.com/llvm/llvm-project/pull/108596