Re: [Evolution-hackers] gcc 4.4 may be causing a number of bugs in Evolution

[Jeffrey Stedfast <fejj novell com>]

Xavier Bestel wrote:
> On Tue, 2010-02-02 at 18:13 +0000, Matthew Barnes wrote:
>   
>> On Tue, 2010-02-02 at 12:27 -0500, Paul Smith wrote:
>>     
>>> Anyway, I agree with you that if Evo makes use of this type of aliasing
>>> then we should definitely add that flag to the default makefile flags.
>>> Configure can check for it and use it if present.
>>>       
>> Done.  Although, I imagine many distros have already disabled strict
>> aliasing optimization due to all the compiler warnings we used to have
>> about it.
>>
>> If GCC or even LLVM ever learns to detect cases like what Jeff ran into
>> and -warn- about them, I'd love to know about it so I can it to our
>> already lengthy list of warning flags we build with by default now.
>>     
>
> I don't know ... Jeff's demonstration was using obviously wrong C code,
> so I'm on GCC side for that one.
>   

It's only wrong if you are targeting c99 (evolution was written to
target c89 - that may have changed a bit since I've left the project,
but the demonstration code is perfectly legal in c89 and works on all of
the big-name compilers).

This type of trick is used all over the place.

In any case, the workaround is to just specify -fno-strict-aliasing.

Jeff