Bug#944127: gfortran-9 causes libcgns FTBFS on ppc64el

[Gilles Filippini <pini@debian.org>]

Hi Matthias,

Matthias Klose a écrit le 04/11/2019 à 19:21 :
> Control: forwarded -1 https://gcc.gnu.org/PR92361
> 
> On 04.11.19 18:13, Gilles Filippini wrote:
>> I've recently uploaded libcgns 8.4.0-1~exp1 to experimental. All
>> builds but ppc64el are ok.
>>
>> The ppc64el failure [0] occurs in the test suite (test cgread_f03),
>> when a C va_arg function (src/cg_ftoc.c:cg_goto_f()) is called from
>> Fortran code (src/tests/cgread_f03.F90:421). This function is called
>> several times. Is is successful at first, then it fails badly because
>> the corresponding hidden string length parameters[1] are equal to 0.
>> This shouldn't happen because the related strings are literals:
>> 'Zone_t', 'GridCoordinates_t', 'end'.
>>
>> [0]https://buildd.debian.org/status/fetch.php?pkg=libcgns&arch=ppc64el&ver=3.4.0-1%7Eexp1&stamp=1572269974&raw=0
>>
>> [1]https://gcc.gnu.org/onlinedocs/gfortran/Argument-passing-conventions.html
>>
>>
>> Further investigation shows that release 3.3.0-6 of libcgns FTBFS the
>> very same way with GCC 8.3.0, while it succeeded with GCC 8.2.0 [2].
>>
>> [2]https://buildd.debian.org/status/fetch.php?pkg=libcgns&arch=ppc64el&ver=3.3.0-6%2Bb2&stamp=1542797186&raw=0
>>
>>
>> I then ran a bisect on the GCC svn branch 'gcc-8-branch' and found out
>> that the failure was introduced by the r269349 changeset [3].
>>
>> [3]https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=269349
>>
>> This is a backport of the trunk r268992 changetset [4] introduced
>> during GCC-9 development.
>>
>> [4]https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=268992
> 
> now forwarded, would be nice to provide to subscribe to the upstream issue.
> is this reproducible with gcc-snapshot?
> any idea for a test case?

Unfortunately it currently doesn't build against gcc-snapshot, and I'm
not at ease with the reported errors.
No idea for a test case. This seems memory related. Very simple tests
cases work AFAICT.

Thanks,

_g.