Bug#838613: perl: FTBFS on hppa - ext/XS-APItest/t/customop FAILED

[John David Anglin]

On 2016-09-25, at 4:09 AM, Niko Tyni wrote:

> On Fri, Sep 23, 2016 at 07:44:13AM -0400, John David Anglin wrote:
>> On 2016-09-23, at 2:24 AM, Niko Tyni wrote:
>>> On Thu, Sep 22, 2016 at 08:49:42PM -0400, John David Anglin wrote:
> 
>>>> Since 5.22.2-4, the ext/XS-APItest/t/customop test fails on hppa and perl
>>>> fails to build from source.  For example, see:
>>>> https://buildd.debian.org/status/fetch.php?pkg=perl&arch=hppa&ver=5.22.2-5&stamp=1474392510
>>> 
>>> There are earlier cases of this on experimental buildds. The oldest I
>>> see is 5.22.1-6. It looks like this regressed with gcc 6.
> 
> I got hppa shell access from Helge, some results:
> 
> - building with gcc-5 or at -O0 makes it go away
> - I've bisected with gcc #pragmas that disabling optimization for just
>  Perl_custom_op_register() in op.c makes it go away
> - I haven't managed to find which specific optimization causes it

Thanks, that's a huge step in narrowing the problem.  If the routine isn't too large,
maybe I can spot problem.  Of course, most optimization bugs are in the core gcc
code.

> 
> If nothing else, we can set the optimization level for op.c to -O0 in
> cflags.SH on hppa. Of course even better if somebody can find a more
> targeted deoptimization and/or the underlying reason (whether a code
> bug or a gcc optimizer one.) I don't intend to work much on that myself.
> 
> As the Perl 5.24 transition is currently ongoing in unstable, I don't
> think we want to do a perl upload for the sake of a non-release arch
> before the transition is over.  At the same time, I expect missing the
> 500+ transition binNMUs from the release team is inconvenient for the
> hppa porters.

Yes.
> 
> Maybe you could manually upload a DEB_BUILD_OPTIONS=noopt build of 5.24
> for now, unless you have a separate hppa-specific package repository
> where a sourceful fix could go?

The perl 5.24 transition is almost done except for a few packages.  I will try the above
this afternoon.  we don't have separate repository.

Dave

--
John David Anglin	dave.anglin at bell.net