[llvm] [AMDGPU] Allocate i1 argument to SGPRs (PR #72461)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

The tests can be in one file (and possibly should just go in the existing ABI tests). They also need quite a few more tests:

1. Test i1 vectors and i1 arrays for a few different sizes
2. Test the case where the SGPR argument list will run out. In particular, test the case where a wave64 argument needs to straddle the boundary
3. Test some mixed other inreg arguments, such that the alignment requirement for the boolean uses matters. e.g. a select user will require even aligned registers, but the argument will be odd

https://github.com/llvm/llvm-project/pull/72461