On Fri, Mar 18, 2016 at 03:21:13PM -0400, Igor Schein wrote:
> Package: pari
> Version: git
>
>           GP/PARI CALCULATOR Version 2.8.0 (development 18700-3cadb51)
>           ix86 running solaris (ix86/GMP-4.3.2 kernel) 32-bit version
>                  compiled: Mar 18 2016, gcc version 4.8.2 (GCC)
>                            threading engine: pthread
>                 (readline v5.2 disabled, extended help enabled)
>
>                      Copyright (C) 2000-2016 The PARI Group
>
> PARI/GP is free software, covered by the GNU General Public License, and
> comes
> WITHOUT ANY WARRANTY WHATSOEVER.
>
> Type ? for help, \q to quit.
> Type ?15 for how to get moral (and possibly technical) support.
>
> parisize = 4000000, primelimit = 500000
>    echo = 1 (on)
> ? bnfisprincipal(bnfinit(x^2-x-57),[5,1;0,1])
>   ***   at top-level: bnfisprincipal(bnfin
>   ***                 ^--------------------
>   *** bnfisprincipal: bug in PARI/GP (Segmentation Fault), please report.
>
> Debug version works fine with pthread.

I do not know how good is the TLS support in this configuration.
Your example does not actually run any threads, so it is purely
a TLS issue.

Could you try
polmodular(127)

Cheers,
Bill