re PR c/4076 (-Wunused doesn't warn about static function only called by itself.)

2007-06-30  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c/4076
	* c-typeck.c (build_external_ref): Don't mark as used if called
	from itself.
	* calls.c (rtx_for_function_call): Likewise.

testsuite/
	* gcc.dg/Wunused-function.c: New.

From-SVN: r126144

gcc/ChangeLog

+2007-06-30  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c/4076
+	* c-typeck.c (build_external_ref): Don't mark as used if called
+	from itself.
+	* calls.c (rtx_for_function_call): Likewise.
+	
 2007-06-30  Richard Sandiford  <richard@codesourcery.com>
 
 	Revert:

gcc/c-typeck.c

@@ -2090,9 +2090,13 @@ build_external_ref (tree id, int fun, location_t loc)
   if (TREE_DEPRECATED (ref))
     warn_deprecated_use (ref);
 
-  if (!skip_evaluation)
-    assemble_external (ref);
-  TREE_USED (ref) = 1;
+  /* Recursive call does not count as usage.  */
+  if (ref != current_function_decl) 
+    {
+      if (!skip_evaluation)
+	assemble_external (ref);
+      TREE_USED (ref) = 1;
+    }
 
   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
     {

gcc/calls.c

@@ -1493,7 +1493,7 @@ rtx_for_function_call (tree fndecl, tree addr)
     {
       /* If this is the first use of the function, see if we need to
 	 make an external definition for it.  */
-      if (! TREE_USED (fndecl))
+      if (!TREE_USED (fndecl) && fndecl != current_function_decl)
 	{
 	  assemble_external (fndecl);
 	  TREE_USED (fndecl) = 1;

gcc/testsuite/ChangeLog

+2007-06-30  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c/4076
+	* gcc.dg/Wunused-function.c: New.
+	
 2007-06-29  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	* gfortran.fortran-torture/compile/inline_1.f90: Fix test.

gcc/testsuite/gcc.dg/Wunused-function.c

+/* PR c/4076  -Wunused doesn't warn about static function only called by itself.  */
+/* { dg-do compile } */
+/* { dg-options "-Wunused-function" } */
+
+static void foo (void) {} /* { dg-warning "'foo' defined but not used" } */
+static void bar (void) { bar (); } /* { dg-warning "'bar' defined but not used" } */