CLEAR_HARD_REG_SET (all_btrs);
for (first_btr = -1, reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
if (TEST_HARD_REG_BIT (reg_class_contents[(int) btr_class], reg)
CLEAR_HARD_REG_SET (all_btrs);
for (first_btr = -1, reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
if (TEST_HARD_REG_BIT (reg_class_contents[(int) btr_class], reg)