Bug#754901: libapache2-mod-perl2: breaks with gcc-4.9

[Matthias Klose]

Am 06.08.2014 um 13:39 schrieb Niko Tyni:
> On Mon, Aug 04, 2014 at 11:36:12PM +0300, Niko Tyni wrote:
>> On Mon, Aug 04, 2014 at 12:13:42PM +0300, Niko Tyni wrote:
>>> On Tue, Jul 15, 2014 at 11:31:52PM +0200, Matthias Klose wrote:
>>>> Am 15.07.2014 20:48, schrieb Niko Tyni:
>>>>> Package: libapache2-mod-perl2
>>>>> Version: 2.0.8+httpd24-r1449661-6
>>>>> Severity: important
>>>>> X-Debbugs-Cc: gcc-4.9 at packages.debian.org
>>>>> Tags: help
>>>>>
>>>>> As seen in #754308, the libapache2-mod-perl2 build segfaults in the
>>>>> test suite when built with gcc 4.9. We have worked around that in
>>>>> 2.0.8+httpd24-r1449661-7 by building with 4.8, but that's not a long
>>>>> term solution.
> 
>>> It works at -O0, modulo #756989 (which happens with gcc-4.8 too
>>> but confused me into thinking this was more than just an optimizer
>>> regression.)
> 
>> It's src/modules/perl/modperl_env.c, and I've narrowed it down to
>> modperl_env_table_populate().
> 
>> I'm now working on a standalone test case but it's not very easy.
>> Any help is appreciated.
> 
> No progress with the test case, but another data point: the optimization
> that triggers this is -ftree-dse.
> 
could you attribute the function with
__attribute__((optimize("STRING")))

e.g. -fno-tree-dse, and build the rest with the default optimization?