Re: [patch, fortran] Remove parallell annotation from DO CONCURRENT

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Apr 10, 2018 at 11:50:44PM +0200, Thomas Koenig wrote:
> Hi Jakub,
> 
> 
> > The new test FAILs everywhere, gfortran.dg doesn't have infrastructure to
> > run -fopenmp, -fopenacc nor -ftree-parallelize-loops= tests.
> > You need to put such tests into libgomp/testsuite/libgomp.fortran/
> 
> I put the test case in the attached form into the libgomp.fortran
> directory, but it failed execution, without error message.
> 
> Anything I could have done differently?

Avoid using that much stack?  ulimit -s is usually around 8MB on Linux, on
other OSes it can be as low as 2MB or even less, so using 160MB edof array
is way too much.  Also, even if you e.g. allocated it from heap rather than
stack (still for some targets it would be too much), isn't that just too
expensive for the testsuite?
Can you reproduce say even with ne = 200000 (with the fix reverted)?

Also, are you going to do the suggested change (because can_be_parallel
is something only autopar cares about, but annot_expr_parallel_kind
sets like annot_expr_ivdep_kind also safelen to INTMAX):
--- gcc/fortran/trans-stmt.c.jj	2018-04-10 08:52:25.467790554 +0200
+++ gcc/fortran/trans-stmt.c	2018-04-11 17:42:40.670493050 +0200
@@ -3643,12 +3643,13 @@ gfc_trans_forall_loop (forall_info *fora
       cond = fold_build2_loc (input_location, LE_EXPR, logical_type_node,
 			      count, build_int_cst (TREE_TYPE (count), 0));
 
-      /* PR 83064 means that we cannot use the annotation if the
-	 autoparallelizer is active.  */
-      if (forall_tmp->do_concurrent && ! flag_tree_parallelize_loops)
+      /* PR 83064 means that we cannot use the annot_expr_parallel_kind
+	 annotation until autopar is tought to handle local variables
+	 in loops annotated that way.  */
+      if (forall_tmp->do_concurrent)
 	cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
 		       build_int_cst (integer_type_node,
-				      annot_expr_parallel_kind),
+				      annot_expr_ivdep_kind),
 		       integer_zero_node);
 
       tmp = build1_v (GOTO_EXPR, exit_label);


> ! { dg-do run }
> ! PR 83064 - this used to give wrong results.
> ! { dg-additional-options "-O3 -ftree-parallelize-loops=2" }
> ! Original test case by Christian Felter
> 
> program main
>     use, intrinsic :: iso_fortran_env
>     implicit none
> 
>     integer, parameter :: nsplit = 4
>     integer(int64), parameter :: ne = 20000000
>     integer(int64) :: stride, low(nsplit), high(nsplit), edof(ne), i
>     real(real64), dimension(nsplit) :: pi

	Jakub