Description:
------------
When i use function ati_add for array of class, it reproduce crash...

When i use this function for list of class only, it working correctly. 
Code
      $data[3] = ati_add($data[0], $data[1], $data[2]);
working perfectly.

Using PHP for Apache2 isapi module

Reproduce code:
---------------
<?php

class ati {
	var $data, $flag;
	function ati($data = null, $flag = null) {
		$this->data = $data;
		$this->flag = $flag;
	}
}

function ati_add() {
	$c = new ati();
	foreach(func_get_args() as $a) {
		if(is_a($a, 'ati')) {
			$c->data += $a->data;
			$c->flag &= $a->flag;
		} else {
			$c = ati_add($a);
		}
	}
	return $c;
}

$data[] = new ati(1,0);
$data[] = new ati(2,0);
$data[] = new ati(3,0);

$data[3] = ati_add($data);

echo $data[3]->data;

?>

Expected result:
----------------
I should see
6

Actual result:
--------------
Crash Apache with PHP (PHP working as isapi module)