On Wed, May 20, 2015 at 02:44:30PM +0100, Ramana Radhakrishnan wrote: > > > On 20/05/15 14:37, David Howells wrote: > >Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > > > >>I was thinking of "y" as a simple variable, but if it is something more > >>complex, then the compiler could do this, right? > >> > >> char *x; > >> > >> y; > >> x = z; > > > >Yeah. I presume it has to maintain the ordering, though. > > The scheduler for e.g. is free to reorder if it can prove there is > no dependence (or indeed side-effects for y) between insns produced > for y and `x = z'. So for example, if y is independent of z, the compiler can do the following: char *x; x = z; y; But the dependency ordering is still maintained from z to x, so this is not a problem. Or am I missing something subtle here? Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
