> This is a soon to be released GCC though I won't deny it has
> regressions, but note that extra optimizations already uncovered bugs in
> other software.

And the GCC authors always win these cases, C standard in hand.

> And unless I can get a minimal C testcase, GCC bug will be worthless.
>
> Exact crashling call is string_tests.py line 255 :
>
> self.checkraises(OverflowError,
>                              '\ta\n\tb', 'expandtabs', sys.maxint)
>
> Commenting out this fixes the crash.

If you want for me to debug this myself it'll be ages. it looks like
the crashing call is

'\ta\n\tb'.expandtabs(2147483647)

Can you confirm that this crashes? If it does, you should be able to
use gdb to step through expandtabs() and hopefully analyze the
problem.