facebook/hhvm — pull request #1707 by tstarling (2014-02-05 03:10:11+00:00)
Title: Pass PCRE_NO_UTF8_CHECK to pcre_exec more often

Code as in https://bugs.php.net/bug.php?id=44336 . Omitting
PCRE_NO_UTF8_CHECK causes a massive performance regression for certain
test cases, giving O(N^2) execution time instead of O(N).