Yeah, the basic block arguments are nice. The one thing that would complicate their use in a low-level IR is that they are awkward in cases where you want to pa

Yeah, the basic block arguments are nice. The one thing that would complicate their use in a low-level IR is that they are awkward in cases where you want to pass different arguments to different successors. If you don't want every control-flow transfer instruction to pass additional per-target args then you have to split edges, but you may have edges that you can't or don't want to split.