memset (new_reg_mask + ax->reg_mask_len, 0,
(new_len - ax->reg_mask_len) * sizeof (ax->reg_mask[0]));
ax->reg_mask_len = new_len;
memset (new_reg_mask + ax->reg_mask_len, 0,
(new_len - ax->reg_mask_len) * sizeof (ax->reg_mask[0]));
ax->reg_mask_len = new_len;