> -----Original Message----- > From: Mike Stump [mailto:[EMAIL PROTECTED] > Sent: Tuesday, April 17, 2007 4:28 PM > To: Eric Weddington > Cc: 'Steven Bosscher'; gcc@gcc.gnu.org; 'Joerg Wunsch'; > 'Anatoly Sokolov' > Subject: Re: GCC -On optimization passes: flag and doc issues > > On Apr 17, 2007, at 2:56 PM, Eric Weddington wrote: > > Well this begs the question of why, when there are so many > > different targets, are there are only 4 optimization flags > > (1,2,3,s), especially when they only get tuned to certain targets? > > If you count again, you'll see there are more than 4 optimization > flags. There are merely four in the set {-O0, -O1, -O2, -O3, - > Os}. :-) There are only 4 in the big-O set, as the poor > users can't > handle more.
Oh? I wonder how that decision was reached... > If you want to tune your target, well, patches welcome. That's exactly what we're trying to do, sarcasm aside. > > "Also, as you mention the target code has a chance to tune > > this ..., can you give me a hint about where to look for > these knobs? > > See override_options (aka OVERRIDE_OPTIONS) in > config/i386/i386.c for > example. See the documentation where this is described. If you > wonder around some more port files, you can find all sorts of cost > things and tuning things, they might give you some addition ideas. Thanks for the suggestion, it's very much appreciated. We'll look into it. > If you set up a regression tester that checks nightly for code size > regressions on your platform and send hate mail whenever one > of these > events happens, you would be one step closer to having no > regressions. Thanks for the suggestion. I'll see what I can do to implement it. > If you maintain your port, and ask others that do the > codesize tests (CSiBE), to also test your platform (if they don't > already), they might be willing to do that. Well, there's part of the problem. Somehow, I don't think that CSiBE testsuite was designed for an 8-bit micro. It will be difficult to do a real comparison. But it's definitely a start if we can tune things from the backend. Eric
