Bug#778163: vim: ftbfs with GCC-5

[Matthias Klose]

On 02/27/2015 07:45 PM, James McCoy wrote:
> On Feb 27, 2015 12:14 PM, "Matthias Klose" <doko at debian.org> wrote:
>>
>> On 02/27/2015 05:27 PM, James McCoy wrote:
>>> On Fri, Feb 13, 2015 at 10:14:03PM -0500, James McCoy wrote:
>>>> On Thu, Feb 12, 2015 at 10:37:46AM +0000, Matthias Klose wrote:
>>>>> The package fails to build in a test rebuild on at least amd64 with
>>>>> gcc-5/g++-5, but succeeds to build with gcc-4.9/g++-4.9.
>>>>
>>>> I eventually narrowed it down to “-O1 -fno-tree-dominator-opts
>>>> -fno-tree-fre” as the minimal set that will cause the build to succeed.
>>>> Dropping either of those -fno-tree-… will cause the build to fail.
>>>>
>>>> This seems like a GCC bug to me.  Let me know if you need more
>>>> information and, more importantly, how to get the right information.
>>>> Note that Vim's source compiles fine in all situations but the tests
>>>> fail when those optimizations aren't disabled.
>>>
>>> I'm still seeing this with the latest gcc-5 upload (5-20150226-1).
>>
>> didn't touch that yet. Can you narrow down the file where this is needed,
> by
>> combining object files from two builds?
> 
> I narrowed it down to src/regexp.c.

cool, you could use the optimize attribute, applied to a single function to
search for the miscompiled function ...