http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59487
--- Comment #7 from GGanesh <Ganesh.Gopalasubramanian at amd dot com> --- Richard! With gcc version 4.9.0 20140224, I could see a gap between with/without -fwhole-program. with -fwhole-program : time ./rnflowWhPr real 0m26.184s user 0m26.018s sys 0m0.156s without -fwhole-program: time ./rnflow real 0m18.251s user 0m18.061s sys 0m0.180s