On Fri, Aug 05, 2011 at 10:54:41AM +0200, Jan de Groot wrote: > On Fri, 2011-08-05 at 15:23 +0800, Ray Rashif wrote: > > > For eg. some developers like to enforce -O3, so they should first get > > the system CFLAGS and override it's -O*, if any. > > > > But in general, I agree. We shouldn't enforce anything either unless > > we're trying to fix something. The ardour PKGBUILD does this [1], > > maybe it shouldn't, but I assume the -O3 becomes redundant when we > > pass system CFLAGS to the build as a configuration flag. > > > > [1] http://projects.archlinux.org/svntogit/packages.git/tree/ardour/trunk/PKGBUILD > > Looking at ardour, I see it's also patched to support gcc 4.6. Now let's > say something about -O3: -O3 optimization can be very bad and the > results are extremely dependent on the compiler version. Something that > works optimal with gcc 4.4 and -O3 can break completely with gcc 4.6 and > -O2. You should file a bug report if it does. Given the number of PKGBUILDs that patch optimization levels, I would also say that this is only true for a minority of cases. > Just adding -O3 to CFLAGS without knowing which compiler is used is > plain stupid. Check this blog for example: > http://glandium.org/blog/?p=1975 > There someone from Mozilla claims they're finally able to build with O3 > +PGO with GCC 4.5. This was at the time we were already doing O2+PGO > from our PKGBUILD with 4.5 and now 4.6.
