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Re: "SSE instruction set disabled?"
> On Wed, Dec 04, 2002 at 02:07:51PM -0500, R. Kelley Cook wrote:
> > >>>From Andrew Pinski:
> > >>> try with the -msse option.
> > >>
> > >> Ah-ha! Thank you.
> > >>
> > >> This makes me wonder if -msse should be implied by -mfpmath=sse, or
> > >> vice versa.
> > >if -mfpmath=sse impled -msse and not -msse2 most people on P4 system
> > >would never enable SSE2 support then.
> > >Perhaps we can drop -msse now and require people to use
> > >non-contradicitng -march=XXX (ie not asking for -mfpmath=sse and
> > >tunning for CPU with no SSE support in it)
> >
> > This makes absolute complete sense.
> >
> > "-mmmx", "-msse", "-msse2", and "-m3dnow" (and their coresponding
> > -mno-xxx) should just go away.
>
> So what do you do if you want your binaries or libraries run on any
> CPU supporting SSE, ie. ATM pIII, p4, athlon-{4,xp,mp}?
> -march=i686 -msse -mfpmath=sse is what you use now, using -march=pentium3
> is not a good idea for the athlons and likewise -march=athlon-xp is
> not a good idea for pentiums.
What makes -march=pentium3 worse for Athlon than -march=pentiumpro ==
i686?
I was thinking about introducing some switch "optimize well for commonly
used CPUs - currently probably Pentium3, Athlon and Pentium4" that can
be used for distribution build.
Some targets do have such a switch, however it's definition seems to be
pretty weak.
Honza
>
> Jakub