Bug#840458: [Debian-science-sagemath] linbox: FTBFS on i386: illegal instruction in test-{cra, charpoly}

[Doug Torrance]

Yes, please do.

On Tue, Nov 29, 2016, 1:52 PM Tobias Hansen <thansen at debian.org> wrote:

> On 11/29/2016 06:01 PM, Tobias Hansen wrote:
> > On 11/29/2016 03:53 PM, Doug Torrance wrote:
> >> Control: reassign -1 src:givaro
> >>
> >> On 11/29/2016 09:58 AM, Tobias Hansen wrote:
> >>> I think I figured out at least the test failures with "Illegal
> >>> instruction" on i386. The problem is that givaro is built using cpu
> >>> extensions that are not allowed.
> >>>
> >>> Jerome figured out in [1] that the problem happens when givaro code is
> >>> called. And sure enough:
> >>>
> >>> objdump -S /usr/lib/i386-linux-gnu/libgivaro.so.9.0.0 | grep
> >>> '\b\(ymm\|zmm\|vfm\)'
> >>>     15411:    c4 e3 79 6b 8b a4 29     vfmaddsd
> >>> %xmm2,-0x1d65c(%ebx),%xmm0,%xmm1
> >>>     154d1:    c4 e3 69 6b 8b ac 29     vfmaddsd
> >>> %xmm0,-0x1d654(%ebx),%xmm2,%xmm1
> >>>
> >>> And in the i386 build logs for givaro there are these flags:
> >>> -mmmx -mpopcnt -msse -msse2 -msse3 -msse4.1 -msse4.2 -msse4a -mavx
> >>> -mfma4 -mfpmath=sse
> >>>
> >>> Do you have time in the next days to disable these flags? Otherwise I
> >>> can do it. (I'm not sure if some of these flags (mmx, sse ?) are
> allowed
> >>> on i386 and didn't find that info. Ximin, do you know this?)
> >>
> >> Sure, I can take a look.  I think it should be a simple --disable-simd
> >> in d/rules (we did the same in fflas-ffpack).
> >>
> >> Doug
> >
> > Thanks! I tried building it but now there seems to be an issue similar
> > to [1]:
> >
> > FAIL: test-ringarith
> > ====================
> >
> > 997167681959697!=997167682008849 failed (at line 123)
> > x y failed !
> > MEDmax failed !
> > FAIL test-ringarith (exit status: 255)
> >
> > And it even fails when setting the flag -ffp-contract=off .
> > Note that now the failure seems to be related to ModularExtended<double>
> > instead of ModularExtended<float> (MEDmax instead of MEFmax in the error
> > message).
> >
> > Best,
> > Tobias
> >
> > [1] https://github.com/linbox-team/givaro/issues/25
>
> Ok, a workaround is to set -ffloat-store (like the Fedora package). I
> pushed this change to the git repo. Can I upload this?
>
> Best,
> Tobias
>
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