re PR middle-end/21728 (Nonlocal goto from an unused nested function)

        PR 21728
        * tree-cfg.c (remove_bb): Transmute DECL_NONLOCAL labels into
        FORCED_LABEL labels.

From-SVN: r102786

gcc/ChangeLog

+2005-08-05  Richard Henderson  <rth@redhat.com>
+
+	PR 21728
+	* tree-cfg.c (remove_bb): Transmute DECL_NONLOCAL labels into
+	FORCED_LABEL labels.
+
 2005-08-05  J"orn Rennecke <joern.rennecke@st.com>
 
 	PR middle-end/23135

gcc/testsuite/gcc.c-torture/compile/pr21728.c

+int main (void)
+{
+  __label__ l1;
+  void __attribute__((used)) q(void)
+  {
+    goto l1;
+  }
+
+  l1:;
+}

gcc/tree-cfg.c

@@ -1983,11 +1983,23 @@ remove_bb (basic_block bb)
     {
       tree stmt = bsi_stmt (i);
       if (TREE_CODE (stmt) == LABEL_EXPR
-          && FORCED_LABEL (LABEL_EXPR_LABEL (stmt)))
+          && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
+	      || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
 	{
-	  basic_block new_bb = bb->prev_bb;
-	  block_stmt_iterator new_bsi = bsi_start (new_bb);
+	  basic_block new_bb;
+	  block_stmt_iterator new_bsi;
+
+	  /* A non-reachable non-local label may still be referenced.
+	     But it no longer needs to carry the extra semantics of
+	     non-locality.  */
+	  if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
+	    {
+	      DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
+	      FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
+	    }
 	  	  
+	  new_bb = bb->prev_bb;
+	  new_bsi = bsi_start (new_bb);
 	  bsi_remove (&i);
 	  bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
 	}