在Codeigniter 3.1.2中构造问题

We have recently updated to Codeigniter 3.1.2 and got one issue.

We have call one controller file to anther controller file using below code.

First Controller :

$this->load->library('../controllers/secondcontroller');
$this->secondcontroller->functionName();

Second Controller :

class Secondcontroller extends CI_Controller
{
public function __construct()
{
    parent::__construct();

    $CI =& get_instance();
    $CI->load->helper(array('form','url','file'));

It was working fine in last version but i have checked that now it not working Codeigniter 3.1.2

Could you please help to change correct code based on version.

Thanks in Advance .