[Bug fortran/83017] DO CONCURRENT not parallelizing

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83017

--- Comment #4 from rguenther at suse dot de <rguenther at suse dot de> ---
On November 16, 2017 1:22:37 PM GMT+01:00, cfztol at hotmail dot com
<gcc-bugzilla@gcc.gnu.org> wrote:
>https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83017
>
>--- Comment #3 from Christian Felter <cfztol at hotmail dot com> ---
>Ultimately, I wanted to compute k like this
>
>k = permutation( j )
>
>where permutation is a 1D array of integers (from 1 to 4, e.g. [ 1, 4,
>2, 1, 3,
>... etc] ). This would allow an easy way of parallelizing the so-called
>"finite
>element assembly procedure". But I guess, this case is even harder.
>Clearly, I
>must have misunderstood the requirements for DO CONCURRENT... Maybe
>they could
>be relaxed ?

It's more an optimization pass issue or the frontend not communicating
guarantees for dependencies downstream. Might be a bit tricky for function
calls.