> On Thu, 25 Oct 2007 13:24:49 +1000
>
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > Hi,
> >
> > Andi spotted this exchange on the gcc list. I don't think he's
> > brought it up here yet, but it worries me enough that I'd like
> > to discuss it.
> >
> > Starts here
> >
http://gcc.gnu.org/ml/gcc/2007-10/msg00266.html
> >
> > Concrete example here
> >
http://gcc.gnu.org/ml/gcc/2007-10/msg00275.html
> >
> > Basically, what the gcc developers are saying is that gcc is
> > free to load and store to any memory location, so long as it
> > behaves as if the instructions were executed in sequence.
>
> this optimization btw is a serious mis-optimization, it makes memory
> more dirty and causes cachelines to become unshared.... I'm sure it
> works great on microbenchmarks but it sucks bigtime for anything real