Re: [proaudio] gcc cflags

[Dominique Michel <dominique.michel@xxxxxxxxxxxx>]

Not sure about -fvisibility-inlines-hidden
I used it before (with gcc-3.4) in CXXFLAGS, but removed it because some program
(I don't remember which) was not compiling with it. I filled a bug report and
get an answer as what it wasn't a bug but this flag... But maybe at this kind of
problem is solved with gcc4.

Dominique

 Le Sat, 2 Sep 2006 19:13:10 -0500,
"Reuben Martin" <reuben.m@xxxxxxxxx> a écrit :

> You will want to add -fvisibility-inlines-hidden to your CXXFLAGS
> 
> On 8/30/06, Dominique Michel <dominique.michel@xxxxxxxxxxxx> wrote:
> > It begin to become clearer. I found a good thread at
> > http://forums.gentoo.org/viewtopic-t-318191-highlight-.html
> >
> > It seam at -fomit-frame-pointer will speedup the code on x86, because
> > it is not enable by default (it make debugging impossible).
> >
> > -momit-leaf-frame-pointer seam to be safe too.
> >
> > -fno-ident is not an optimisation flag, but it remove some useless
> > repeated version strings, and it is safe.
> >
> > -fweb seam to not do much, but doesn't break anything.
> >
> > -ffast-math can have really good effect on audio/video decoders, but don't
> > use it as global CFLAGS.
> >
> > -ftracer: I am 100% not sure about it. Seam to be a good thing.
> >
> > -ftree-vectorize seam to be good too.
> >
> > So, I thing at I will try with:
> > CFLAGS="-O2 -march=pentium4 -pipe -fweb -ftracer -ftree-vectorize
> > -fomit-frame-pointer -momit-leaf-frame-pointer -fno-ident"
> >
> > CXXFLAGS="${CFLAGS}"
> >
> > LDFLAGS="-Wl,-O1 -Wl,--sort-common"
> >
> > BTW, gcc-4.1 go stable just now.
> >
> > Dominique
> >
> >  Le Thu, 24
> > Aug 2006 17:17:19 +0200, Dominique Michel
> > <dominique.michel@xxxxxxxxxxxx> a écrit :
> >
> > > Thank you,
> > > The vectorize flags are for loop optimisation. I read on the IBM website
> > > at they can increase the speed of a program by a factor of 20. But I
> > > read in another website at all depend of the size of the loop, because
> > > they append additional structure control to the code, and at in case of
> > > small loops, those additional structures will do the resulting program
> > > slower.
> > >
> > > I think at it will be a good flag to have with math intensive programs
> > > as multimedia programs, but I am not sure at it is a good flag to have
> > > as a system flag. Do you know something about this issue?
> > >
> > > On Wed, 23 Aug 2006 16:20:18 -0500
> > > "Reuben Martin" <reuben.m@xxxxxxxxx> wrote:
> > >
> > > > Based on how agressive you seem to want to be, I would recommend:
> > > >
> > > > CFLAGS="-O2 -march=pentium4 -pipe -ftracer -fweb -ftree-vectorize"
> > > >
> > > > The -ftree-vectorize does wonders.
> > > >
> > > > If you are still feeling like you want to push it a little harder you
> > > > can try changing -O2 to -O3 and adding -ffast-math. Some things don't
> > > > work well with -O3 though (some of the LADSPA plugins don't work right
> > > > with -O3) and some programs don't work correctly with -ffast-math.
> > > > (for instance OpenOffice will fail to compile if Python has been built
> > > > with -ffast-math turned on)
> > > >
> > > > -Reuben
> > > >
> > >
> > > I don't use -ffast-math and don't want it. I have no problem at this
> > > time with -O3 and -fforce-addr, and that even to compile the LADSPA
> > > plugin or openoffice. The only problem is at the resulting code is
> > > bigger as with -O2 alone and at it seam to be not faster. I
> > > try to remove the -fforce-addr and tested it with the nec2 antenna
> > > simulation software. It was faster as with -O2 alone, but I get wrong
> > > simulation results in some cases. So I thing at I will get with -O2 in
> > > the future, -O3 is not a good option is you have to remove the speed
> > > benefice of that option in order to get a correct code with all the
> > > programs. And I don't have the time to test my flags with every one
> > > program that I want to install.
> > >
> > > Cheers,
> > > Dominique
> > >
> >
> >
>