https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69196
--- Comment #7 from Jeffrey A. Law <law at redhat dot com> --- It's definitely the FSM threader. The FSM threader has 3 knobs for tuning. If I crank them all down to minimal values, then the trunk & gcc-5 actually generate slightly smaller code than gcc-4.9. I don't think Sebastian did a lot of tuning on those params and with the increased reliance on the FSM threader on the trunk those params likely need some rethinking.
