[PATCH] Use OMP_RETURN_NOWAIT in tree-parloops.c

[Sebastian Pop]

The change looks good, but I cannot approve it.

Sebastian

On Tue, May 6, 2008 at 3:28 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
>  While looking at PR36106, I've noticed that tree-parloops.c
>  doesn't ever make the created #pragma omp for nowait.  While when
>  the parallelized loop doesn't have reductions remove_exit_barrier
>  will most likely optimize that barrier out, if there are reductions it
>  won't, as there is code in between OMP_FOR's OMP_RETURN and OMP_PARALLEL's
>  OMP_RETURN.
>  But IMNSHO there is no point in a barrier after the loop, like normal
>  reductions the reduction code is just doing #pragma omp atomic addition
>  to a shared variable, adding a private var to it.  autopar testsuite
>  coverage is very limited, but this patch certainly doesn't break
>  any of the autopar.exp tests (which are all compile time though)
>  nor libgomp.c/autopar-1.c from the PR36106 patch.
>
>  Ok for trunk?
>
>  2008-05-06  Jakub Jelinek  <jakub@redhat.com>
>
>         * tree-parloops.c (create_parallel_loop): Set OMP_RETURN_NOWAIT
>         on OMP_RETURN for OMP_FOR.
>
>  --- gcc/tree-parloops.c.jj      2008-04-25 21:49:50.000000000 +0200
>  +++ gcc/tree-parloops.c 2008-05-05 22:54:49.000000000 +0200
>  @@ -1,5 +1,5 @@
>   /* Loop autoparallelization.
>  -   Copyright (C) 2006, 2007 Free Software Foundation, Inc.
>  +   Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
>     Contributed by Sebastian Pop <pop@cri.ensmp.fr> and
>     Zdenek Dvorak <dvorakz@suse.cz>.
>
>  @@ -1639,7 +1639,9 @@ create_parallel_loop (struct loop *loop,
>
>    /* Emit OMP_RETURN for OMP_FOR.  */
>    bsi = bsi_last (ex_bb);
>  -  bsi_insert_after (&bsi, make_node (OMP_RETURN), BSI_NEW_STMT);
>  +  t = make_node (OMP_RETURN);
>  +  OMP_RETURN_NOWAIT (t) = 1;
>  +  bsi_insert_after (&bsi, t, BSI_NEW_STMT);
>
>    return paral_bb;
>   }
>
>
>         Jakub
>