http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55996
--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> 2013-02-21 12:36:46 UTC --- Patch to make DF-scan dumps cleaner and speed up complete re-scanning and deferred rescanning: http://gcc.gnu.org/ml/gcc-patches/2013-02/msg00961.html