On 15 Mar 2022 12:41, Richard Earnshaw wrote:
> On 15/03/2022 03:25, Mike Frysinger wrote:
> > __builtin_mul_overflow showed up with gcc-5, so stub it out for older
> > versions.
> > ---
> >   newlib/libc/include/sys/cdefs.h | 4 ++++
> >   1 file changed, 4 insertions(+)
> > 
> > diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cdefs.h
> > index da729092185c..e51f7f4b873a 100644
> > --- a/newlib/libc/include/sys/cdefs.h
> > +++ b/newlib/libc/include/sys/cdefs.h
> > @@ -416,6 +416,10 @@
> >   #define	__unreachable()	((void)0)
> >   #endif
> >   
> > +#if !__GNUC_PREREQ__(5, 0)
> > +#define __builtin_mul_overflow(a, b, size) ({ *(size) = (a) * (b); 0; })
> 
> Wouldn't
> (*(size) = (a) * (b), 0)
> 
> be more portable (avoiding the GNU statement expression extension)?

sure, that works too, thanks
-mike