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

[Tobias Hansen]

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