[Fortran] Fix/modify present() handling for assumed-shape optional (PR 94672)

gcc/fortran/
2020-05-07  Tobias Burnus  <tobias@codesourcery.com>

	PR fortran/94672
	* trans.h (gfc_conv_expr_present): Add use_saved_decl=false argument.
	* trans-expr.c (gfc_conv_expr_present): Likewise; use DECL directly
	and only if use_saved_decl is true, use the actual PARAM_DECL arg (saved
	descriptor).
	* trans-array.c (gfc_trans_dummy_array_bias): Set local 'arg.0'
	variable to NULL if 'arg' is not present.
	* trans-openmp.c (gfc_omp_check_optional_argument): Simplify by checking
	'arg.0' instead of the true PARM_DECL.
	(gfc_omp_finish_clause): Remove setting 'arg.0' to NULL.

gcc/testsuite/
2020-05-07  Jakub Jelinek  <jakub@redhat.com>
	    Tobias Burnus  <tobias@codesourcery.com>

	PR fortran/94672
	* gfortran.dg/gomp/pr94672.f90: New.
	* gfortran.dg/missing_optional_dummy_6a.f90: Update scan-tree.

1 files changed, 4 insertions, 38 deletions

diff --git a/gcc/fortran/trans-openmp.c b/gcc/fortran/trans-openmp.c
index 6666955..42ecd0a 100644
--- a/gcc/fortran/trans-openmp.c
+++ b/gcc/fortran/trans-openmp.c
@@ -90,16 +90,13 @@ gfc_omp_check_optional_argument (tree decl, bool for_present_check)
   if (!DECL_LANG_SPECIFIC (decl))
     return NULL_TREE;
 
-  bool is_array_type = false;
+  tree orig_decl = decl;
 
   /* For assumed-shape arrays, a local decl with arg->data is used.  */
   if (TREE_CODE (decl) != PARM_DECL
       && (GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (decl))
 	  || GFC_ARRAY_TYPE_P (TREE_TYPE (decl))))
-    {
-      is_array_type = true;
-      decl = GFC_DECL_SAVED_DESCRIPTOR (decl);
-    }
+    decl = GFC_DECL_SAVED_DESCRIPTOR (decl);
 
   if (decl == NULL_TREE
       || TREE_CODE (decl) != PARM_DECL
@@ -132,23 +129,8 @@ gfc_omp_check_optional_argument (tree decl, bool for_present_check)
       return decl;
     }
 
-  tree cond = fold_build2_loc (input_location, NE_EXPR, boolean_type_node,
-			       decl, null_pointer_node);
-
-  /* Fortran regards unallocated allocatables/disassociated pointer which
-     are passed to a nonallocatable, nonpointer argument as not associated;
-     cf. F2018, 15.5.2.12, Paragraph 1.  */
-  if (is_array_type)
-    {
-      tree cond2 = build_fold_indirect_ref_loc (input_location, decl);
-      cond2 = gfc_conv_array_data (cond2);
-      cond2 = fold_build2_loc (input_location, NE_EXPR, boolean_type_node,
-			       cond2, null_pointer_node);
-      cond = fold_build2_loc (input_location, TRUTH_ANDIF_EXPR,
-			      boolean_type_node, cond, cond2);
-    }
-
-  return cond;
+  return fold_build2_loc (input_location, NE_EXPR, boolean_type_node,
+			  orig_decl, null_pointer_node);
 }
 
 
@@ -1287,22 +1269,6 @@ gfc_omp_finish_clause (tree c, gimple_seq *pre_p)
 	return;
       tree orig_decl = decl;
 
-      /* For nonallocatable, nonpointer arrays, a temporary variable is
-	 generated, but this one is only defined if the variable is present;
-	 hence, we now set it to NULL to avoid accessing undefined variables.
-	 We cannot use a temporary variable here as otherwise the replacement
-	 of the variables in omp-low.c will not work.  */
-      if (present && GFC_ARRAY_TYPE_P (TREE_TYPE (decl)))
-	{
-	  tree tmp = fold_build2_loc (input_location, MODIFY_EXPR,
-				      void_type_node, decl, null_pointer_node);
-	  tree cond = fold_build1_loc (input_location, TRUTH_NOT_EXPR,
-				       boolean_type_node, present);
-	  tmp = build3_loc (input_location, COND_EXPR, void_type_node,
-			    cond, tmp, NULL_TREE);
-	  gimplify_and_add (tmp, pre_p);
-	}
-
       c4 = build_omp_clause (OMP_CLAUSE_LOCATION (c), OMP_CLAUSE_MAP);
       OMP_CLAUSE_SET_MAP_KIND (c4, GOMP_MAP_POINTER);
       OMP_CLAUSE_DECL (c4) = decl;