On Sun, Apr 22, 2007 at 04:39:23PM -0700, Joe Buck wrote: > > On Sun, 2007-04-22 at 14:44 +0200, Richard Guenther wrote: > > > At work we use -O3 since it gives 5% performance gain against -O2. > > > profile-feedback has many flags and there is no overview of it in the > > > doc IIRC. Who will use it except GCC developpers? Who knows about your > > > advice? > > On Sun, Apr 22, 2007 at 03:22:56PM +0200, Jan Hubicka wrote: > > Well, this is why -fprofile-generate and -fprofile-use was invented. > > Perhaps docs can be improved so people actually discover it. Do you > > have any suggestions? > > Docs could be improved, but this also might be a case where a tutorial > would be needed, to teach users how to use it effectively. > > > (Perhaps a chapther for FDO or subchapter of gcov docs would do?)
We could also have examples, with lots of comments, in the testsuite, with references to them in the docs. That way there is code that people can try to see what kind of effect an optimization has on their system. This would also, of course, provide at least minimal testing for more optimizations; last time I looked there were lots of them that are never used in the testsuite. Janis
