> On Fri, 17 Aug 2007, Paul E. McKenney wrote:
>
> > On Sat, Aug 18, 2007 at 08:09:13AM +0800, Herbert Xu wrote:
> > > On Fri, Aug 17, 2007 at 04:59:12PM -0700, Paul E. McKenney wrote:
> > > >
> > > > gcc bugzilla bug #33102, for whatever that ends up being worth. ;-)
> > >
> > > I had totally forgotten that I'd already filed that bug more
> > > than six years ago until they just closed yours as a duplicate
> > > of mine :)
> > >
> > > Good luck in getting it fixed!
> >
> > Well, just got done re-opening it for the third time. And a local
> > gcc community member advised me not to give up too easily. But I
> > must admit that I am impressed with the speed that it was identified
> > as duplicate.
> >
> > Should be entertaining! ;-)
>
> Right. ROTFL... volatile actually breaks atomic_t instead of making it
> safe. x++ becomes a register load, increment and a register store. Without
> volatile we can increment the memory directly. It seems that volatile
> requires that the variable is loaded into a register first and then
> operated upon. Understandable when you think about volatile being used to
> access memory mapped I/O registers where a RMW operation could be
> problematic.
>
> See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3506
