Le Thu, May 29, 2014 at 12:21:06PM -0700, Russ Allbery a écrit : > Xavier Roche <xav...@debian.org> writes: > > > I have a rather silly question: most (all ?) packages are built by > > default with -02 - something which is inherited from autotool's '-g -O2' > > default flagsd, I presume. > > > Is -O3 considered too dangerous ? (AFAICS, potential issues are mainly > > present in O2) Or is it considered worthless because the performance > > gain would be really low ? > > Historically, -O3 has usually been slower than -O2 for a lot of software > because the aggressive loop unrolling increases code size and interferes > with processor caching strategies. I don't know if that's now been fixed > in GCC, but that's probably much of the historical reason. > > My impression is that most people using GCC use -O2, so it's the > best-tested path.
Perhaps we can stop overriding this option ? For a lot of scientific packages, -O3 is chosen by the upstream author, and I always feel bad that if we make the programs slower by overriding it to -O2, it will reflect poorly on Debian as a distribution for scientific works. Have a nice day, -- Charles Plessy Debian Med packaging team, http://www.debian.org/devel/debian-med Tsurumi, Kanagawa, Japan -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20140529222108.ga23...@falafel.plessy.net
