That's very good to hear. What's not good is that code that relied on nothing like backreferencing regexps got squashed in the upgrade process. Like
japhy guessed, the regexp failed to match, but wouldn't it make sense even for a
/(.*)TEXT\1/ regexp to first look for
/TEXT/ and then worry about getting the appropriate group match (be it greedy or reluctant)? This slowing down is a terrible shock some people might get (including me) when moving old code to new code. But on another note, I do agree I'm a long way from mastering regular expressions.