if (VM.VerifyAssertions) VM._assert(VM.NOT_REACHED);
  private static void returnExpand (OPT_Instruction s, OPT_IR ir) {    OPT_PhysicalRegisterSet phys = ir.regpool.getPhysicalRegisterSet();    if (MIR_Return.hasVal(s)) {      OPT_RegisterOperand symb1 = MIR_Return.getClearVal(s);      OPT_RegisterOperand phys1;      if (symb1.type.isFloatType() || symb1.type.isDoubleType()) {        phys1 = D(phys.get(FIRST_DOUBLE_RETURN));        s.insertBack(MIR_Move.create(PPC_FMR, phys1, symb1));      } else {        phys1 = new OPT_RegisterOperand(phys.get(FIRST_INT_RETURN), symb1.type);        s.insertBack(MIR_Move.create(PPC_MOVE, phys1, symb1));      }      MIR_Return.setVal(s, phys1.copyD2U());    }    if (MIR_Return.hasVal2(s)) {      OPT_RegisterOperand symb2 = MIR_Return.getClearVal2(s);      OPT_RegisterOperand phys2 = R(phys.get(FIRST_INT_RETURN + 1));      s.insertBack(MIR_Move.create(PPC_MOVE, phys2, symb2));      MIR_Return.setVal2(s, phys2.copyD2U());    }  }