------- Comment #6 from rguenther at suse dot de 2009-04-25 14:17 -------
Subject: Re: gcc-4.4 -Wstrict-aliasing and
-Wstrict-aliasing=3 behaves like -Wstrict-aliasing=2 in gcc-4.3
On Sat, 25 Apr 2009, edwintorok at gmail dot com wrote:
> ------- Comment #4 from edwintorok at gmail dot com 2009-04-25 14:12 -------
> (In reply to comment #3)
> >
> > The above is properly optimized. Why do you think that an inline
> > function taking void * would fix anything?
>
> I can't know if memcpy will be inlined, it may just be a function call on
> certain systems, with certain compilers.
> The inline function should be a more portable way of expressing what I need,
> and it shouldn't cause any bugs with -fstrict-aliasing, since gcc already
> knows
> I gave my pointer to a function taking void*, so anything could happen with
> it,
> right?
No, not if it is inlined (and if not you can as well use memcpy).
You can also do (GCC extension)
union union_t {
unsigned un;
char c[4];
};
unsigned bar(char *x)
{
union union_t u;
u.c[0] = x[0];
u.c[1] = x[1];
u.c[2] = x[2];
u.c[3] = x[3];
return u.un;
}
but that will even generate worse code with GCC than the
memcpy (it's even horrible code).
Richard.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39895
