expr.c (gfc_check_assign): Add comment.

fortran/
* expr.c (gfc_check_assign): Add comment. Add new warning.
* trans-expr.c (gfc_conv_function_call): Correctly dereference
 result of pointer valued function when not in pointer assignment.

testsuite/
* gfortran.dg/assignment_1.f90: New test.

From-SVN: r86585

gcc/fortran/ChangeLog

+2004-08-25  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
+
+	* expr.c (gfc_check_assign): Add comment. Add new warning.
+	* trans-expr.c (gfc_conv_function_call): Correctly dereference
+ 	result of pointer valued function when not in pointer assignment.
+
 2004-08-25  Paul Brook  <paul@codesourcery.com>
 
 	* config-lang.in: Remove dead commented line.

gcc/fortran/expr.c

@@ -1797,10 +1797,19 @@ gfc_check_assign (gfc_expr * lvalue, gfc_expr * rvalue, int conform)
       return FAILURE;
     }
 
+  /* This is a guaranteed segfault and possibly a typo: p = NULL()
+     instead of p => NULL()  */
   if (rvalue->expr_type == EXPR_NULL)
     gfc_warning ("NULL appears on right-hand side in assignment at %L",
 		 &rvalue->where);
 
+  /* This is possibly a typo: x = f() instead of x => f()  */
+  if (gfc_option.warn_surprising 
+      && rvalue->expr_type == EXPR_FUNCTION
+      && rvalue->symtree->n.sym->attr.pointer)
+    gfc_warning ("POINTER valued function appears on right-hand side of "
+		 "assignment at %L", &rvalue->where);
+
   /* Check size of array assignments.  */
   if (lvalue->rank != 0 && rvalue->rank != 0
       && gfc_check_conformance ("Array assignment", lvalue, rvalue) != SUCCESS)

gcc/fortran/trans-expr.c

@@ -1170,6 +1170,13 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
   se->expr = build3 (CALL_EXPR, TREE_TYPE (fntype), se->expr,
 		     arglist, NULL_TREE);
 
+  /* If we have a pointer function, but we don't want a pointer, e.g.
+     something like
+        x = f()
+     where f is pointer valued, we have to dereference the result.  */
+  if (sym->attr.pointer && !se->want_pointer && !byref)
+    se->expr = gfc_build_indirect_ref (se->expr);
+
   /* A pure function may still have side-effects - it may modify its
      parameters.  */
   TREE_SIDE_EFFECTS (se->expr) = 1;

gcc/testsuite/ChangeLog

+2004-08-25  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
+
+	* gfortran.dg/assignment_1.f90: New test.
+
 2004-08-25  Adam Nemet  <anemet@lnxw.com>
 
 	* g++.dg/template/repo3.C: New test.

gcc/testsuite/gfortran.dg/assignment_1.f90

+! { dg-do run }
+! { dg-options -Wsurprising }
+integer, pointer :: p
+integer, target :: t, s
+
+! The tests for character pointers are currently commented out,
+! because they don't yet work correctly.
+! This is PR 17192
+!!$character*5, pointer :: d
+!!$character*5, target :: c, e
+
+t = 1
+p => s
+! We didn't dereference the pointer in the following line.
+p = f() ! { dg-warning "POINTER valued function" "" }
+p = p+1
+if (p.ne.2) call abort()
+if (p.ne.s) call abort()
+
+!!$! verify that we also dereference correctly the result of a function 
+!!$! which returns its result by reference
+!!$c = "Hallo"
+!!$d => e
+!!$d = g() !  dg-warning "POINTER valued function" "" 
+!!$if (d.ne."Hallo") call abort()
+
+contains
+function f()
+integer, pointer :: f
+f => t
+end function f
+!!$function g()
+!!$character, pointer :: g
+!!$g => c
+!!$end function g
+end