> Hi, > > On Mon, 15 Apr 2019, Martin Liška wrote: > > > There's a similar comparison that I did for the official openSUSE gcc > > packages. gcc8 is built with PGO, while the gcc9 package is built in 2 > > different configurations: PGO, LTO, PGO+LTO (LTO used for FE in stage4, > > for generators in stage3 as well). > > > > Please take a look at attached statistics. > > It seems the C++ parser got quite a bit slower with gcc 9 :-( Most visible > in the compile time for tramp-3d (24%) and kdecore.cc (18% slower with > just PGO); it seems that the other .ii files are C-like enough to not > trigger this behaviour, so it's probably something to do with templates > and/or classes.
Would be possible to have -ftime-report for your tramp3d build with the four compilers? It may be a consequence of training changes and i.e. template instantiation code which is excercised by tramp3d a lot more than by GCC bootstrap. But it still seem bit too much for simple PGO divergence. It also may be caused by changes of inliner decisions or some other pass being overly active. Honza > > > Ciao, > Michael.
