Description:
------------
preg_grep messes up the given array.

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

$array=Array(1,2,3);

debug_zval_dump($array); echo "<br>\n";

debug_zval_dump(preg_grep('/asdf/',$array)); echo "<br>\n";

while(list($key,$value)=each($array)) echo "Array: ".$value." ";

echo "<br>\n";

debug_zval_dump($array); echo "<br>\n";

?>

Expected result:
----------------
array(3) refcount(2){ [0]=> long(1) refcount(1) [1]=> long(2) refcount(1) [2]=> long(3) refcount(1) } 
array(0) refcount(1){ } 
Array: 1 Array: 2 Array: 3 
array(3) refcount(2){ [0]=> long(1) refcount(1) [1]=> long(2) refcount(1) [2]=> long(3) refcount(1) } 

Actual result:
--------------
----PHP6 Build Jan 20 2008 18:04:22----
array(3) refcount(2){ [0]=> long(1) refcount(1) [1]=> long(2) refcount(1) [2]=> long(3) refcount(1) } 
array(0) refcount(1){ } 

array(3) refcount(2){ [0]=> long(1) refcount(1) [1]=> long(2) refcount(1) [2]=> long(3) refcount(1) } 

-----PHP5.2.5
array(3) refcount(2){ [0]=> long(1) refcount(1) [1]=> long(2) refcount(1) [2]=> long(3) refcount(1) } 
array(0) refcount(1){ } 

array(3) refcount(2){ [0]=> string(1) "1" refcount(1) [1]=> string(1) "2" refcount(1) [2]=> string(1) "3" refcount(1) }