[J3] [EXTERNAL] Re: Question regarding valid set of values

[Clune, Thomas L. (GSFC-6101)]

I've nothing to add about legality, but ...  I checked just a couple of compilers, and they all seem to loop forever.     I'd have thought at -O3 that some would delete the loop as it produces no output, but that was also not the case.   So then I switched to 

Program foo
    n = huge(n)
   do i = 0, n
   end do
end

Here one compiler completed immediately even at -O0, while the other still looped forever.   

On 5/24/21, 6:31 AM, "J3 on behalf of Thomas König via J3" <j3-bounces at mailman.j3-fortran.org on behalf of j3 at mailman.j3-fortran.org> wrote:


    On 21.05.21 08:17, Malcolm Cohen via J3 wrote:
    > I really would prefer the standard to be a lot more specific in this 
    > area, but it is far from the top of my list of inadequacies that I’d 
    > like to see fixed. If anyone else wants to knock themselves out 
    > rigorously defining what is and isn’t allowed, and what the results of 
    > intrinsics operations are, go right ahead! I don’t think it is as easy 
    > as it looks though, and getting general agreement for a big change of 
    > wording with little or no technical effect is likely tough. As they say, 
    > “if it ain’t broke...”

    There are a few point which might get clarified along the way.
    For example, I am currently not sure if

    program foo
       integer :: i
       do i=0,huge(i)
       end do
    end

    is legal or not (as long as the value of i is not subsequently used).