Re: [gentoo-dev] [PATCH] profiles/arch/amd64: add "-mfpmath=sse" to CFLAGS_x86

[Mike Gilbert]

On Tue, Oct 18, 2022 at 9:37 AM David Seifert <soap@g.o> wrote:
>
> On Tue, 2022-10-18 at 13:40 +0200, Ulrich Mueller wrote:
> > > > > > > On Tue, 18 Oct 2022, David Seifert wrote:
> >
> > > > > -CFLAGS_x86="-m32"
> > > > > +CFLAGS_x86="-m32 -mfpmath=sse"
> >
> > > -mfpmath=sse is already the default on amd64.
> >
> > I see. This change makes sense then.
> >
> > What about profiles/arch/x86 though? IIUC we'll end up with an
> > inconsistency between x86 and multilib amd64.
> >
> > Ulrich
>
> What if I want to build Gentoo on an old AMD Thunderbird which has
> neither SSE1 nor the more important SSE2?

Right. On amd64 CPU always supports SSE2, so -mfpmath=sse will always
work there.

On x86, we need to consider a more diverse set of supported instructions.