[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.

5 files changed, 38 insertions, 51 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 005f686..a1a625a 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,6 +1,19 @@
+2020-05-11  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.
+
 2020-05-11  Janus Weil  <janus@gcc.gnu.org>
 	    Dominique d'Humieres  <dominiq@lps.ens.fr>
-    
+
 	PR fortran/59107
 	* gfortran.h: Rename field resolved as resolve_symbol_called
 	and assign two 2 bits instead of 1.
diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index 9c928d0..434960c 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -6787,9 +6787,11 @@ gfc_trans_dummy_array_bias (gfc_symbol * sym, tree tmpdesc,
 		      && sym->attr.dummy));
   if (optional_arg)
     {
-      tmp = gfc_conv_expr_present (sym);
-      stmtInit = build3_v (COND_EXPR, tmp, stmtInit,
-			   build_empty_stmt (input_location));
+      tree zero_init = fold_convert (TREE_TYPE (tmpdesc), null_pointer_node);
+      zero_init = fold_build2_loc (input_location, MODIFY_EXPR, void_type_node,
+				   tmpdesc, zero_init);
+      tmp = gfc_conv_expr_present (sym, true);
+      stmtInit = build3_v (COND_EXPR, tmp, stmtInit, zero_init);
     }
 
   /* Cleanup code.  */
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 030edc1..33fc061 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -1712,12 +1712,12 @@ gfc_make_safe_expr (gfc_se * se)
    Also used for arguments to procedures with multiple entry points.  */
 
 tree
-gfc_conv_expr_present (gfc_symbol * sym)
+gfc_conv_expr_present (gfc_symbol * sym, bool use_saved_desc)
 {
-  tree decl, cond;
+  tree decl, orig_decl, cond;
 
   gcc_assert (sym->attr.dummy);
-  decl = gfc_get_symbol_decl (sym);
+  orig_decl = decl = gfc_get_symbol_decl (sym);
 
   /* Intrinsic scalars with VALUE attribute which are passed by value
      use a hidden argument to denote the present status.  */
@@ -1744,10 +1744,13 @@ gfc_conv_expr_present (gfc_symbol * sym)
       return cond;
     }
 
-  if (TREE_CODE (decl) != PARM_DECL)
+  /* Assumed-shape arrays use a local variable for the array data;
+     the actual PARAM_DECL is in a saved decl.  As the local variable
+     is NULL, it can be checked instead, unless use_saved_desc is
+     requested.  */
+
+  if (use_saved_desc && TREE_CODE (decl) != PARM_DECL)
     {
-      /* Array parameters use a temporary descriptor, we want the real
-         parameter.  */
       gcc_assert (GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (decl))
              || GFC_ARRAY_TYPE_P (TREE_TYPE (decl)));
       decl = GFC_DECL_SAVED_DESCRIPTOR (decl);
@@ -1761,9 +1764,12 @@ gfc_conv_expr_present (gfc_symbol * sym)
      we thus also need to check the array descriptor.  For BT_CLASS, it
      can also occur for scalars and F2003 due to type->class wrapping and
      class->class wrapping.  Note further that BT_CLASS always uses an
-     array descriptor for arrays, also for explicit-shape/assumed-size.  */
+     array descriptor for arrays, also for explicit-shape/assumed-size.
+     For assumed-rank arrays, no local variable is generated, hence,
+     the following also applies with !use_saved_desc.  */
 
-  if (!sym->attr.allocatable
+  if ((use_saved_desc || TREE_CODE (orig_decl) == PARM_DECL)
+      && !sym->attr.allocatable
       && ((sym->ts.type != BT_CLASS && !sym->attr.pointer)
 	  || (sym->ts.type == BT_CLASS
 	      && !CLASS_DATA (sym)->attr.allocatable
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;
diff --git a/gcc/fortran/trans.h b/gcc/fortran/trans.h
index 69171f3..bd96cdf 100644
--- a/gcc/fortran/trans.h
+++ b/gcc/fortran/trans.h
@@ -561,7 +561,7 @@ void gfc_trans_common (gfc_namespace *);
 void gfc_conv_structure (gfc_se *, gfc_expr *, int);
 
 /* Return an expression which determines if a dummy parameter is present.  */
-tree gfc_conv_expr_present (gfc_symbol *);
+tree gfc_conv_expr_present (gfc_symbol *, bool use_saved_decl = false);
 /* Convert a missing, dummy argument into a null or zero.  */
 void gfc_conv_missing_dummy (gfc_se *, gfc_expr *, gfc_typespec, int);