On 26 October 2007 17:28, Andrew Haley wrote:
> Richard Guenther writes:
> > >
> > > This is legal POSIX threads code: counter is not accessed when we do
> > > not hold the mutex. According to POSIX we do not have to declare
> > > volatile memory that we only access when we hold a mutex.
> >
> > I hope we're not trying to support such w/o volatile counter.
>
> I think we have to: not just for POSIX, but for the Linux kernel too.
>
> > Whatever POSIX says, this would pessimize generic code too much.
>
> We don't have to do it for non-threaded code.
I certainly won't object to any move to prohibit the
read-conditional-add-write (and related) optimisation(s) when compiling with
an option that explicitly specifies that we are compiling multi-threaded code.
cheers,
DaveK
--
Can't think of a witty .sigline today....
