OpenACC's tile clause fix for implicit typing (PR93825)

2020-02-20  Tobias Burnus  <tobias@codesourcery.com>

	PR fortran/93825
	* openmp.c (resolve_oacc_loop_blocks): Move call to
	resolve_oacc_nested_loops from here ...
	(resolve_oacc_loop): ... to here.

	PR fortran/93825
	* gfortran.dg/goacc/tile-3.f90: New.

gcc/fortran/ChangeLog

+2020-02-20  Tobias Burnus  <tobias@codesourcery.com>
+
+	PR fortran/93825
+	* openmp.c (resolve_oacc_loop_blocks): Move call to
+	resolve_oacc_nested_loops from here ...
+	(resolve_oacc_loop): ... to here.
+
 2020-02-18  Mark Eggleston  <markeggleston@gcc.gnu.org>
 
 	PR fortran/93714

gcc/fortran/openmp.c

@@ -6192,10 +6192,8 @@ resolve_oacc_loop_blocks (gfc_code *code)
   if (code->ext.omp_clauses->tile_list)
     {
       gfc_expr_list *el;
-      int num = 0;
       for (el = code->ext.omp_clauses->tile_list; el; el = el->next)
 	{
-	  num++;
 	  if (el->expr == NULL)
 	    {
 	      /* NULL expressions are used to represent '*' arguments.
@@ -6213,7 +6211,6 @@ resolve_oacc_loop_blocks (gfc_code *code)
 			   &code->loc);
 	    }
 	}
-      resolve_oacc_nested_loops (code, code->block->next, num, "tiled");
     }
 }
 
@@ -6266,6 +6263,18 @@ resolve_oacc_loop (gfc_code *code)
   do_code = code->block->next;
   collapse = code->ext.omp_clauses->collapse;
 
+  /* Both collapsed and tiled loops are lowered the same way, but are not
+     compatible.  In gfc_trans_omp_do, the tile is prioritized.  */
+  if (code->ext.omp_clauses->tile_list)
+    {
+      int num = 0;
+      gfc_expr_list *el;
+      for (el = code->ext.omp_clauses->tile_list; el; el = el->next)
+	++num;
+      resolve_oacc_nested_loops (code, code->block->next, num, "tiled");
+      return;
+    }
+
   if (collapse <= 0)
     collapse = 1;
   resolve_oacc_nested_loops (code, do_code, collapse, "collapsed");

gcc/testsuite/ChangeLog

+2020-02-20  Tobias Burnus  <tobias@codesourcery.com>
+
+	PR fortran/93825
+	* gfortran.dg/goacc/tile-3.f90: New.
+
 2020-02-19  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/93169 - wrong-code with a non-constexpr constructor.

gcc/testsuite/gfortran.dg/goacc/tile-3.f90

+! { dg-do compile }
+!
+! PR fortran/93825
+!
+! Check that implicit typing works
+
+program p
+   !$acc parallel loop tile(2,2)
+   do i = 1, 8
+      do j = 1, 8
+      end do
+   end do
+end