re PR fortran/12841 (passing null to a subroutine)

fortran/
PR fortran/12841
* interface.c (compare_parameter, compare_actual_formal): Don't
check types and array shapes for NULL()
* trans-expr.c (conv_function_call): No double indirection for
NULL()
( I had accidentally committed the interface.c part before)

testuite/
PR fortran/12841
* gfortran.fortran-torture/execute/null_arg.f90: New test.

From-SVN: r83028

gcc/fortran/ChangeLog

+2004-06-12  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
+
+	PR fortran/12841
+	* interface.c (compare_parameter, compare_actual_formal): Don't
+	check types and array shapes for NULL()
+	* trans-expr.c (conv_function_call): No double indirection for
+	NULL() 
+
 2004-06-09  Toon Moene  <toon@moene.indiv.nluug.nl>
 
 	* trans-expr.c (gfc_conv_cst_int_power): Compute

gcc/fortran/trans-decl.c

@@ -1923,7 +1923,7 @@ generate_local_decl (gfc_symbol * sym)
       /* warn for unused variables, but not if they're inside a common
 	 block.  */
       else if (warn_unused_variable && !sym->attr.in_common)
-        warning ("unused variable `%s'", sym->name);
+	warning ("unused variable `%s'", sym->name);
     }
 }
 

gcc/fortran/trans-expr.c

@@ -1100,10 +1100,12 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
 	  if (argss == gfc_ss_terminator)
             {
 	      gfc_conv_expr_reference (&parmse, arg->expr);
-              if (formal && formal->sym->attr.pointer)
+              if (formal && formal->sym->attr.pointer
+		  && arg->expr->expr_type != EXPR_NULL)
                 {
                   /* Scalar pointer dummy args require an extra level of
-                     indirection.  */
+                     indirection. The null pointer already contains
+		     this level of indirection.  */
                   parmse.expr = gfc_build_addr_expr (NULL, parmse.expr);
                 }
             }

gcc/testsuite/gfortran.fortran-torture/execute/nullarg.f90

+! This is the testcase from PR 12841. We used to report a type/rank mismatch
+! when passing NULL() as an argument to a function.
+   MODULE T
+   PUBLIC :: A
+   CONTAINS
+   SUBROUTINE A(B)
+   REAL, POINTER :: B
+   IF (ASSOCIATED(B)) CALL ABORT()
+   END SUBROUTINE A
+   END MODULE T
+   USE T
+   CALL A(NULL())
+   END