re PR c++/17796 (Too many unused parameter warnings emitted.)

	PR c++/17796
	* optimize.c (update_cloned_parm): Add FIRST parameter. Use it.
	(maybe_clone_body): Track the first clone.

From-SVN: r105415

gcc/cp/ChangeLog

+2005-10-14  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/17796
+	* optimize.c (update_cloned_parm): Add FIRST parameter. Use it.
+	(maybe_clone_body): Track the first clone.
+
 2005-10-13  Nathan Sidwell  <nathan@codesourcery.com>
 
 	PR c++/23984

gcc/cp/optimize.c

@@ -45,7 +45,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 
 /* Prototypes.  */
 
-static void update_cloned_parm (tree, tree);
+static void update_cloned_parm (tree, tree, bool);
 
 /* CLONED_PARM is a copy of CLONE, generated for a cloned constructor
    or destructor.  Update it to ensure that the source-position for
@@ -53,7 +53,7 @@ static void update_cloned_parm (tree, tree);
    debugging generation code will be able to find the original PARM.  */
 
 static void
-update_cloned_parm (tree parm, tree cloned_parm)
+update_cloned_parm (tree parm, tree cloned_parm, bool first)
 {
   DECL_ABSTRACT_ORIGIN (cloned_parm) = parm;
 
@@ -63,7 +63,7 @@ update_cloned_parm (tree parm, tree cloned_parm)
   /* The definition might have different constness.  */
   TREE_READONLY (cloned_parm) = TREE_READONLY (parm);
 
-  TREE_USED (cloned_parm) = TREE_USED (parm);
+  TREE_USED (cloned_parm) = !first || TREE_USED (parm);
 
   /* The name may have changed from the declaration.  */
   DECL_NAME (cloned_parm) = DECL_NAME (parm);
@@ -79,6 +79,7 @@ bool
 maybe_clone_body (tree fn)
 {
   tree clone;
+  bool first = true;
 
   /* We only clone constructors and destructors.  */
   if (!DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
@@ -118,7 +119,7 @@ maybe_clone_body (tree fn)
       parm = DECL_ARGUMENTS (fn);
       clone_parm = DECL_ARGUMENTS (clone);
       /* Update the `this' parameter, which is always first.  */
-      update_cloned_parm (parm, clone_parm);
+      update_cloned_parm (parm, clone_parm, first);
       parm = TREE_CHAIN (parm);
       clone_parm = TREE_CHAIN (clone_parm);
       if (DECL_HAS_IN_CHARGE_PARM_P (fn))
@@ -130,7 +131,7 @@ maybe_clone_body (tree fn)
       for (; parm;
 	   parm = TREE_CHAIN (parm), clone_parm = TREE_CHAIN (clone_parm))
 	/* Update this parameter.  */
-	update_cloned_parm (parm, clone_parm);
+	update_cloned_parm (parm, clone_parm, first);
 
       /* Start processing the function.  */
       start_preparsed_function (clone, NULL_TREE, SF_PRE_PARSED);
@@ -206,6 +207,7 @@ maybe_clone_body (tree fn)
       finish_function (0);
       BLOCK_ABSTRACT_ORIGIN (DECL_INITIAL (clone)) = DECL_INITIAL (fn);
       expand_or_defer_fn (clone);
+      first = false;
     }
   pop_from_top_level ();