Description:
------------
Hello, everybody.

I noticed a problem while parsing XML with interlocked foreach loops : if I 
write 'continue 2' to continue the upper loop, this will consume virtual memory 
far faster than with a single 'continue' or 'break'.

In my exemple, I parse a small basic XML; when I use 'continue 2', I see that as 
much as 8MB are used for this tiny loop. (See actual result)

On the other hand, only around 256kB are used if I replace this 'continue 2' 
with 'break 2' (See expected result).

As you can see, this 'continue 2' leads the script to retain much more memory 
than needed, and that this virtual memory is retained even if the loops 
allocating this memory are finished. Furthermore, we used the 'continue 2' 
version on a server when parsing a 37MB XML file, and this leaded the script to 
fail because the OS prevented it to claim more than 2GB of virtual memory; as 
you can see, this isn't only a theoritical issue.

Awaiting a bugfix,

Regards.

Test script:
---------------
function testOpCache(){
  $tab1 = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
  $tab2 = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j');
  $tab3 = array(1 => 'a', 2 => 'b', 3 => 'c', 4 => 'd', 5 => 'e', 6 => 'f', 7 => 'g', 8 => 'h', 9 => 'i', 10 => 'j');
  
  $xml = "
    <level1>
      <level2>info1</level2>
      <level2>info2</level2>
      <level2>info3</level2>
      <level2>info4</level2>
      <level2>info5</level2>
      <level2>
        <level3>subinfo1</level3>
        <level3>subinfo2</level3>
        <level3>subinfo3</level3>
        <level3>subinfo4</level3>
        <level3>
          <level4>subsubinfo1</level4>
          <level4>subsubinfo2</level4>
          <level4>subsubinfo3</level4>
          <level4>subsubinfo4</level4>
        </level3>
        <level3>
          <level4>subsubinfo1</level4>
          <level4>subsubinfo2</level4>
          <level4>subsubinfo3</level4>
          <level4>subsubinfo4</level4>
        </level3>
        <level3>
          <level4>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
          </level4>
          <level4>subsubinfo2</level4>
          <level4>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
          </level4>
          <level4>subsubinfo4</level4>
        </level3>
      </level2>
      <level2>
        <level3>subinfo1</level3>
        <level3>subinfo2</level3>
        <level3>subinfo3</level3>
        <level3>subinfo4</level3>
        <level3>
          <level4>subsubinfo1</level4>
          <level4>subsubinfo2</level4>
          <level4>subsubinfo3</level4>
          <level4>subsubinfo4</level4>
        </level3>
        <level3>
          <level4>subsubinfo1</level4>
          <level4>subsubinfo2</level4>
          <level4>subsubinfo3</level4>
          <level4>subsubinfo4</level4>
        </level3>
        <level3>
          <level4>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
          </level4>
          <level4>subsubinfo2</level4>
          <level4>subsubinfo3</level4>
          <level4>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
            <level5>aaa</level5>
          </level4>
        </level3>
      </level2>
    </level1>
  ";
  $dom = simplexml_load_string($xml);
  $tab4 = array();

  sm();
  foreach($tab1 as $t1){
    foreach($tab2 as $t2){
      foreach($tab3 as $t3){
        foreach($dom->xpath('/level1/level2') as $level2){
          foreach($level2->xpath('level3') as $level3){
            foreach($level3->xpath('level4') as $level4){
              foreach($level4->xpath('level5') as $level5){
                continue 2;
                //break 2;
              }
            }
          }
        }
      }
    }
  }
  sm();
}

function sm(){
  echo memory_get_usage()."\n";
}

testOpCache();


Expected result:
----------------
thomas@Koenig:~$ php /home/thomas/Desktop/tests/opcache-1.php 
239224
240120
thomas@Koenig:~$

Actual result:
--------------
thomas@Koenig:~$ php /home/thomas/Desktop/tests/opcache-1.php 
239200
8416616
thomas@Koenig:~$