Description:
------------
How to free gmp resources?
i need a function like gmp_free() to free gmp resources.

Reproduce code:
---------------
<?
function M($p){
return gmp_sub(gmp_pow(2,$p),1);
}
function S($i){
 for($tmm=4,$j=0;$j<$i;$j++){
  $tm1=gmp_pow($tmm,2);//gmp does not free memery,that is problem
  $tm2=gmp_sub($tm1,2);
  $tmm=$tm2;
 }
 return $tmm;
}
$p=31;
echo $mp=gmp_strval(M($p));
if(0==gmp_strval(gmp_mod(S($p-2),$mp))){echo 'yes';}else{echo 'no';}
?>

Expected result:
----------------
it should output a 'yes' or 'no'.
need it tell me : is the number a prime number

Actual result:
--------------
[kee212@localhost ecc]$ php c.php
2147483647PHP Fatal error:  Allowed memory size of 536870912 bytes exhausted (tried to allocate 335806464 bytes) in /var/www/html/kee212/ecc/c.php on line 8

Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 335806464 bytes) in /var/www/html/kee212/ecc/c.php on line 8