Bug#578295: perl (powerpc/experimental): FTBFS: uselongdouble problems

[Niko Tyni]

On Sun, Apr 18, 2010 at 09:04:45PM +0300, Niko Tyni wrote:
> Package: perl
> Version: 5.12.0-1
> Severity: important
> User: debian-perl at lists.debian.org
> Usertags: perl-5.12-transition
> 
> The powerpc build failed:
> 
> Failed 5 tests out of 1752, 99.71% okay.
>     ../cpan/Math-BigInt/t/bare_mbi.t
>     ../cpan/Math-BigInt/t/bigintpm.t
>     ../cpan/Math-BigInt/t/sub_mbi.t
>     op/inc.t
>     op/pack.t
> 
> The failures are almost certainly related to -Duselongdouble, as
> they didn't show up on 5.12.0~rc3-1, which only had -Duse64bitint.

At least op/pack.t also fails on 5.10.1 with -Duselongdouble, so
this is not a 5.12 regression.

I see the 128-bit long doubles are quite special on ppc32: they are
actually a sum of two 64-bit doubles, which is not IEEE compliant [1] and
"has serious arithmetic anomalies" [2].

While this should certainly be forwarded upstream, I doubt we can do
anything else for 5.12.0 than disable -Duselongdouble on powerpc.

[1] http://en.wikipedia.org/wiki/Long_double
[2] http://gcc.gnu.org/ml/gcc-help/2006-10/msg00138.html 
-- 
Niko Tyni   ntyni at debian.org