Description:
------------
If a paranthesised sub expression matches more then ~4999996 chars, no data will be inserted into the &matches array.

Reducing by 1 the number in str_repeat will cause the script to work.

I have tested this with PHP 4.4.0-gentoo-amd64, 5.0.4-FC4, and 5.0.5-gentoo and all exhebit the same problems. 

The configure line is different on all platforms. php.ini is the default. On the FC4 test there is a 512Mb memory limit.

Reproduce code:
---------------
<?php
  $xml_clean = '<data>';
  $xml_clean .= str_repeat('a',4999996);
  $xml_clean .= '</data>';
  $ret = preg_match("/(<([\w]+)[^>]*>)(.*?)(<\/\\2>)/s", $xml_clean, $match);

  print_r($match);
?>


Expected result:
----------------
Array
(
    [0] => <data>aaa(...)aaa</data>
    [1] => <data>
    [2] => data
    [3] => aaa(...)aaa
    [4] => </data>
)


Actual result:
--------------
Array
(
)