Hi Steve,

> On Mon, Apr 09, 2018 at 10:10:13PM +0200, Thomas Koenig wrote:
>>
>> the attached patch removes the parallel annotation from DO CONCURRENT.
>> As discussed in the PR, the autoparallellizer currently generates
>> wrong code. The only feasible way is to disable the annotation for
>> gcc-8 and work on the wrong-code issues for gcc-9. This is an 8
>> regression.
>>
>> Regression-tested. OK for trunk?
>>
> 
> Yes.

Thanks for the review!

However, just as I was about to commit, I thought of something else
and, hopefully, better.

The underlying problem is that the annotation does not go together
with -ftree-parallelize-loops - so let's simply not set it if that
flag is set.

This way, we can avoid speed regressions for people who do not use
-ftree-parallelize-loops, and it will be possible to downgrade the
PR to a missed-optimization bug; it is also not necessary to xfail
vect-do-concurrent-1.f90

Regression-tested. OK for trunk, for this version?


2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/83064
         * trans-stmt.c (gfc_trans_forall_loop): Remove annotation for
         parallell processing of DO CONCURRENT -ftree-parallelize-loops
         is set.

2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/83064
         * gfortran.dg/do_concurrent_5.f90: New test.
         * gfortran.dg/vect/vect-do-concurrent-1.f90: Adjust dg-bogus
         message.