Re: x86 FP issues (Re: [gentoo-dev] Arch Status and Future Plans)

["Michał Górny" <mgorny@gentoo.org>]

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On Wed, 2024-06-26 at 01:20 +0100, Sam James wrote:
> Arthur Zamarin <arthurzam@gentoo.org> writes:
> 
> > Hi all, this will be a long mail, and might be confusing, I'll try to
> > organize it, but this is a mess, so bear with me.
> > [...]
> > ======== 32-bit arches ========
> > 
> > This includes stable arches x86, arm, ppc, sparc32, dev arches s390, and
> > maybe more. Those are in much worse situation, with a mess on various
> > fronts, some of them super hard to continue support. For example
> > qtwebengine is less and less likely to manage to compile on a
> > real-hardware, and not 32-bit chroot on 64-bit host. Arch Team want to
> > minimize our work on those arches, meaning mass-destable and even
> > mass-dekeyword, with potentially full drop of stable status.
> > 
> > ======== x86 ========
> > 
> > Stable 32-bit arch. I'll be honest, I don't believe at all this should
> > be stable arch anymore. I propose making it dev arch, and mass-dekeyword
> > stuff we got because of inertia. This arch is close to HW die. (let's
> > not talk about i486 vs i686).
> 
> I think the mfpmath=sse thing [0] makes this a bit better but I still
> sympathise with your point.

I'd just like to point out that `-mfpmath=sse` is a two-edged sword.  It
generally makes results more consistent with other architectures which
is good and resolves some test failures when people *aren't testing with
x86*.  However, it breaks stuff when people are specifically testing
with x86 and accounting for i387 math (sigh).

> 
> [0] https://public-inbox.gentoo.org/gentoo-dev/ce894afe6c2b324fef012da9bb9387cfde7aed03.camel@gentoo.org/

-- 
Best regards,
Michał Górny


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