On Fri, Jul 08, 2016 at 10:33:45AM +0200, Martin Liška wrote:
> On 07/07/2016 04:40 PM, Jan Hubicka wrote:
> >>
> >> Why is the behavior only undefined for step 1 if the last iteration IV
> >> increment overflows?
> >> Doesn't this apply to all step values?
> >
> > This is what Fortran standard says:
> >
> > The iteration count is established and is the value of the expression
> > (m2-m1+m3)/m3 unless that value is negative,
> > in which case the iteration count is 0.
> >
> > My reading of this is that the do statement is undefined whenever the
> > expression above is undefined
> > (m1 is lower bound, m2 is upper bound, m3 is step) and because I think the
> > evaulation order of
> > m2-m1+m3 is not fixed, I think the statement is not defined whethever
> > (m2-m1), (m1+m3) or (m2-m1)+m3
m1+m3? Did you mean m3-m1 or -m1+m3 instead?
Jakub
