Description:
------------
the 1st code make apache crash, and the 2nd make apache freeze, taking full cpu usage
notice that the "exit" statement is important
noting will happend when "exit" is removed

only class methods is affected, not function


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

class A
{
	function &getInstance()
	{
		if (empty($GLOBALS['a'])) {
			$GLOBALS['a'] = &new A();
		}
		return $GLOBALS['a'];
	}
}

$a = &A::getInstance();
exit;

?>

freeze:
<?php

class A
{
	function &getInstance()
	{
		return $GLOBALS['a'];
	}
}

$a = &A::getInstance();
exit;

?>