http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56688
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> 2013-03-22
14:24:14 UTC ---
(In reply to comment #3)
> (In reply to comment #1)
> > because it appears that 'save' makes all variables global ones.
>
> But this is maybe a frontend issue ? The visibility of x is local to the this
> subroutine, but its lifetime extends over the entire run (so different to your
> variable z in the C testcase).
No, same for
int x[1024], y[1024];
void foo (void)
{
static int z;
unsigned i;
for (i = 0; i < 1024; ++i)
{
z = x[i] - y[i];
x[i] = z;
}
}
(missed optimization is that the variable and the store to it is not
removed completely).
