[clang] [llvm] [AMDGPU] Extend __builtin_amdgcn_sched_group_barrier to support rules. (PR #85304)

[Jeffrey Byrnes via cfe-commits]

jrbyrnes wrote:

Updated the PR as discussed offline.

Support the variadic builtin arg via combining into mask for intrinsic. This sort of implies a limit of 64 rules, but we can workaround by add a new intrinsic with two masks (to support rules 65-128), and so on.

For now, rules in this PR behave as they do in the existing code (that is, they are additional inclusion criteria). Any changes to this will be addressed in future PR.

https://github.com/llvm/llvm-project/pull/85304