I thought I'd make a 5x speedup to the run-time of the regex matching, but I was comparing the wrong version and the improvement actually came from one of your patches yesterday - maybe this one: http://gcc.gnu.org/ml/gcc-patches/2014-04/msg01725.html
Nice work! My changes don't seem to make anything worse, and the first one makes a big improvement to the worst case performance of std::wregex.