https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121439
--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> --- at -O2: So for the gimple level passes: DSE, FRE/PRE take the longest time (just a quick control C in gdb) But rtl passes take over half of the time so for me combine has taken over 20 minutes (maybe closer to 30) and it seems it is still not done. But the memory usage is just staying steady at 1.4G.
