http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54337
Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target| |x86_64-*-* Status|UNCONFIRMED |RESOLVED Version|unknown |4.7.1 Resolution| |DUPLICATE --- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-21 08:09:55 UTC --- Sort-of "confirmed", though you should expect compile-time increases from -O0 to -O[123] and I don't think the increases are unreasonable, esp. for C++ code which can see a lot if inlining. > /usr/bin/time g++-4.7 -S -o /dev/null t.C -O0 2.24user 0.09system 0:02.84elapsed 82%CPU (0avgtext+0avgdata 918736maxresident)k 22384inputs+0outputs (97major+62614minor)pagefaults 0swaps > /usr/bin/time g++-4.7 -S -o /dev/null t.C -O1 11.24user 0.15system 0:11.43elapsed 99%CPU (0avgtext+0avgdata 1045616maxresident)k 0inputs+0outputs (0major+113102minor)pagefaults 0swaps > /usr/bin/time g++-4.7 -S -o /dev/null t.C -O2 16.67user 0.38system 0:17.12elapsed 99%CPU (0avgtext+0avgdata 1189056maxresident)k 2504inputs+0outputs (11major+199132minor)pagefaults 0swaps > /usr/bin/time g++-4.7 -S -o /dev/null t.C -O3 17.79user 0.30system 0:18.20elapsed 99%CPU (0avgtext+0avgdata 1203280maxresident)k 328inputs+0outputs (2major+200860minor)pagefaults 0swaps -O3 time-report: alias stmt walking : 2.87 (16%) usr 0.02 ( 4%) sys 2.96 (16%) wall 1 kB ( 0%) ggc tree PTA : 4.59 (26%) usr 0.01 ( 2%) sys 4.63 (25%) wall 1313 kB ( 1%) ggc so I think we have a duplicate for this kind of issue. SCCVN walks over non-aliased stores are not limited and can expose quadratic complexity if there are no aliases in the function that stop the walk. PR46590 comes to my mind which already tracks this. *** This bug has been marked as a duplicate of bug 46590 ***