Description:
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I'm trying to replace some multiple tags like <wsb></wsb> and <wsimg> with only one regex. While I was using few tags, I saw no problem (what indicates that the regex is valid), but when the tags reaches some unknown limit, the system makes very odd things, like:

- Not parsing correctly the text
- Taking much more time to proccess the script if just one small new line is inserted

You can see theese glitches in 3 files I've prepared. All 3 have similar contents, I just changed one line between them.

Reproduce code:
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Variations:
1: http://wstec.net/tmp/php_bug_pcre_02/code_01.txt
2: http://wstec.net/tmp/php_bug_pcre_02/code_02.txt
3: http://wstec.net/tmp/php_bug_pcre_02/code_03.txt

Actual result:
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Attention to the line with the <wsx />

1: http://wstec.net/tmp/php_bug_pcre_02/code_01.php
- Took more than 1 second to parse the text only 2 times
- Parsed everything as it should be parsed
- Note that there aren't spaces in the text among <!-- and -->

2: http://wstec.net/tmp/php_bug_pcre_02/code_02.php
- Took more than 1 second to parse the text only 1 time
- Not everything that should be parsed was
- Note the only difference is the spaces in the text among <!-- and -->

3: http://wstec.net/tmp/php_bug_pcre_02/code_03.php
- Took less than 1 second to parse the text the same 2 times than the firs scipt
- Parsed everything as it should be parsed
- Note that the only difference between the previous scripts is that line starting with <wsx />

I hope you understand the issue now