-> [instr] -- ^ accumulator for instructions already processed.
-> BlockId -- ^ the id of the current block, for debugging
-> LiveInstr instr -- ^ the instr to have its regs allocated, with liveness info.
-> [instr] -- ^ accumulator for instructions already processed.
-> BlockId -- ^ the id of the current block, for debugging
-> LiveInstr instr -- ^ the instr to have its regs allocated, with liveness info.