BL _ params -> usage (params, callClobberedRegs)
BCTRL params -> usage (params, callClobberedRegs)
ADD reg1 reg2 ri -> usage (reg2 : regRI ri, [reg1])
BL _ params -> usage (params, callClobberedRegs)
BCTRL params -> usage (params, callClobberedRegs)
ADD reg1 reg2 ri -> usage (reg2 : regRI ri, [reg1])