case v.Type.IsMemory():
				// Schedule stores as early as possible. This tends to
				// reduce register pressure.
				score[v.ID] = ScoreMemory
			case v.Op == OpSelect0 || v.Op == OpSelect1 || v.Op == OpSelectN:
				// Tuple selectors need to appear immediately after the instruction
				// that generates the tuple.
				score[v.ID] = ScoreReadTuple
			case v.hasFlagInput():