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Re: 64bit: C++ templates


On May 27 16:39, marco atzeri wrote:
> Il 5/27/2013 3:22 PM, Corinna Vinschen ha scritto:
> >On May 27 14:49, marco atzeri wrote:
> >>Il 5/27/2013 1:15 PM, Corinna Vinschen ha scritto:
> >>>On May 27 12:59, marco atzeri wrote:
> >>>>Il 5/27/2013 12:42 PM, Corinna Vinschen ha scritto:
> >>>>>On May 27 12:22, marco atzeri wrote:
> >>>>>>Il 5/27/2013 11:53 AM, Corinna Vinschen ha scritto:
> >>>>>>>
> >>>>>>>And worse, the problem goes away when building without optimization.
> >>>>>>>There might be another GCC bug lurking in the background...
> >>>>>>>
> >>>>>>
> >>>>>>Probably there is more than one.
> >>>>>>I hit a gcc-4.8 optimization bug testing slang, the workaround
> >>>>>>was to build the 64 bit package without any optimization.
> >>>>>
> >>>>>slang is written in c++?
> >>>>
> >>>>in C
> >>>
> >>>And you built it with the default -mcmodel=medium, I assume.  Well,
> >>>it's not that gcc would be entirely bug free and 4.8.1 is lurking
> >>>around the corner already.  Any chance to create a simple testcase?
> >>
> >>default -mcmodel=medium
> >>
> >>Slang is a small library and the failure is
> >>during "make check" when UTF8 is not used
> >>
> >>http://mailman.jedsoft.org/pipermail/slang-users-l/2013/000788.html
> >
> >Hmm.  For some reason that reminds me of the problem we had with the
> >localtime changes two weeks ago.  Just out of curiosity, would you mind
> >to try an optimized build again, but this time add the -fwrapv option?
> 
> it works, thanks

Wow, I haven't actually believed this would help.  Given it's apparent
dangerousness, wouldn't it make sense to enable the -fwrapv option (or,
FWIW, disabling the -fstrict-overflow option) by default with -O2, at
least on x86_64?  

Kai?  Yaakov?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat


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