> 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?
Ah yes, -m1+m3. But I am by no means language expert - this was meant as a heads up to Fortran people :) Honza > > Jakub
