Bug#164554: gcc-3.2: volatile not respected on alpha

[Daniel Jacobowitz <dan@debian.org>]

On Tue, Oct 15, 2002 at 08:28:02AM +1000, Herbert Xu wrote:
> On Mon, Oct 14, 2002 at 06:01:24PM -0400, Daniel Jacobowitz wrote:
> > 
> > I don't see the problem.  Volatile in C doesn't provide any sort of
> > barrier; you have to place one yourself if you want one.  It only
> > guaranatees that the two accesses to "i" will not be reordered or
> > eliminated.
> 
> My copy of C99 says:
> 
> 5    The least requirements on a conforming implementation are:
>      - At sequence points, volatile objects are stable in the sense that previou
>      s accesses are
>          complete and subsequent accesses have not yet occurred.

Only volatile objects are required to be stable.  I believe that if "j"
were volatile, then you'd see the behaviour you want; but I don't
believe accesses to non-volatile objects have the same requirements.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer