http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55354
--- Comment #25 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-23 08:20:40 UTC --- Have you considered using __builtin_expect to help the compiler in the performance sensitive code? Or even better would be profile-feedback, build libtsan once, run some benchmark, build libtsan again.