re PR fortran/38487 (Bogus Warning: INTENT(INOUT) actual argument might interfere with actual argument)

2008-12-15  Mikael Morin  <mikael.morin@tele2.fr>

	PR fortran/38487
	* gfortran.dg/elemental_dependency_2.f90: New test.

2008-12-15  Mikael Morin  <mikael.morin@tele2.fr>

	PR fortran/38487
	* dependency.c (gfc_is_data_pointer): New function.
	(gfc_check_argument_var_dependency): Disable the warning
	in the pointer case.
	(gfc_check_dependency): Use gfc_is_data_pointer.

From-SVN: r142766

gcc/fortran/ChangeLog

@@ -1,3 +1,11 @@
+2008-12-15  Mikael Morin  <mikael.morin@tele2.fr>
+
+	PR fortran/38487
+	* dependency.c (gfc_is_data_pointer): New function.
+	(gfc_check_argument_var_dependency): Disable the warning
+	in the pointer case.
+	(gfc_check_dependency): Use gfc_is_data_pointer.
+
 2008-12-15  Mikael Morin  <mikael.morin@tele2.fr>
 
 	PR fortran/38113

gcc/fortran/dependency.c

@@ -422,6 +422,24 @@ gfc_ref_needs_temporary_p (gfc_ref *ref)
 }
 
 
+static int
+gfc_is_data_pointer (gfc_expr *e)
+{
+  gfc_ref *ref;
+
+  if (e->expr_type != EXPR_VARIABLE)
+    return 0;
+
+  if (e->symtree->n.sym->attr.pointer)
+    return 1;
+  for (ref = e->ref; ref; ref = ref->next)
+    if (ref->type == REF_COMPONENT && ref->u.c.component->attr.pointer)
+      return 1;
+
+  return 0;
+}
+
+
 /* Return true if array variable VAR could be passed to the same function
    as argument EXPR without interfering with EXPR.  INTENT is the intent
    of VAR.
@@ -447,7 +465,9 @@ gfc_check_argument_var_dependency (gfc_expr *var, sym_intent intent,
       if (gfc_ref_needs_temporary_p (expr->ref)
 	  || gfc_check_dependency (var, expr, !elemental))
 	{
-	  if (elemental == ELEM_DONT_CHECK_VARIABLE)
+	  if (elemental == ELEM_DONT_CHECK_VARIABLE
+	      && !gfc_is_data_pointer (var)
+	      && !gfc_is_data_pointer (expr))
 	    {
 	      /* Elemental procedures forbid unspecified intents, 
 		 and we don't check dependencies for INTENT_IN args.  */
@@ -664,7 +684,6 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
 {
   gfc_actual_arglist *actual;
   gfc_constructor *c;
-  gfc_ref *ref;
   int n;
 
   gcc_assert (expr1->expr_type == EXPR_VARIABLE);
@@ -700,17 +719,8 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
 
 	  /* If either variable is a pointer, assume the worst.  */
 	  /* TODO: -fassume-no-pointer-aliasing */
-	  if (expr1->symtree->n.sym->attr.pointer)
+	  if (gfc_is_data_pointer (expr1) || gfc_is_data_pointer (expr2))
 	    return 1;
-	  for (ref = expr1->ref; ref; ref = ref->next)
-	    if (ref->type == REF_COMPONENT && ref->u.c.component->attr.pointer)
-	      return 1;
-
-	  if (expr2->symtree->n.sym->attr.pointer)
-	    return 1;
-	  for (ref = expr2->ref; ref; ref = ref->next)
-	    if (ref->type == REF_COMPONENT && ref->u.c.component->attr.pointer)
-	      return 1;
 
 	  /* Otherwise distinct symbols have no dependencies.  */
 	  return 0;

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2008-12-15  Mikael Morin  <mikael.morin@tele2.fr>
+
+	PR fortran/38487
+	* gfortran.dg/elemental_dependency_2.f90: New test.
+
 2008-12-14  Paul Thomas  <pault@gcc.gnu.org>
 
 	PR fortran/35937

gcc/testsuite/gfortran.dg/elemental_dependency_2.f90

@@ -0,0 +1,36 @@
+! { dg-do compile }
+!
+! PR fortran/38487
+! Spurious warning on pointers as elemental subroutine actual arguments
+!
+! Contributed by Harald Anlauf <anlauf@gmx.de>
+
+module gfcbug82
+  implicit none
+  type t
+    real, pointer :: q(:) =>NULL()
+    real, pointer :: r(:) =>NULL()
+  end type t
+  type (t), save :: x, y
+  real, dimension(:), pointer, save :: a => NULL(), b => NULL()
+  real, save :: c(5), d
+contains
+  elemental subroutine add (q, r)
+    real, intent (inout) :: q
+    real, intent (in)    :: r
+    q = q + r
+  end subroutine add
+
+  subroutine foo ()
+      call add (y% q, x% r)
+      call add (y% q, b   )
+      call add (a   , x% r)
+      call add (a   , b   )
+      call add (y% q, d   )
+      call add (a   , d   )
+      call add (c   , x% r)
+      call add (c   , b   )
+  end subroutine foo
+end module gfcbug82
+
+! { dg-final { cleanup-modules "gfcbug82" } }