[Bug regression/40665] dereferencing type-punned pointer warnings cannot be disabled

["pinskia at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from pinskia at gmail dot com  2009-07-07 03:50 -------
Subject: Re:  dereferencing type-punned pointer warnings cannot be disabled

Thus code is undefined you have an acess of a char array as a struct.  
Yes you are only taking the address of an element but it is still  
considered an acess by the standards.

Sent from my iPhone

On Jul 6, 2009, at 6:34 PM, "mikulas at artax dot karlin dot mff dot  
cuni dot cz" <gcc-bugzilla@gcc.gnu.org> wrote:

>
>
> ------- Comment #2 from mikulas at artax dot karlin dot mff dot cuni  
> dot cz  2009-07-07 01:34 -------
> Created an attachment (id=18146)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18146&action=view)
> --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18146&action=view)
> a bug in -Wstrict-aliasing=3
>
> This is an example of a flaw in -Wstrict-aliasing=3 (this mode is  
> very bad,
> produces many false positives on my project and I'm wondering why is  
> it
> default?)
>
> Gcc man page says that -Wstrict-aliasing=3 produces less false  
> positives than
> -Wstrict-aliasing=2. This is counterexample, it produces "type- 
> punned" warning
> in -Wstrict-aliasing=3 mode and doesn't warn in -Wstrict-aliasing=2.  
> I added
> (void *) casts everywhere, but they don't quash the warning.
>
>
> -- 
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40665
>


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40665