re PR debug/31899 (-g and using declaration causing ICE in reference_to_unused)

2007-10-03  Doug Kwan  <dougkwan@google.com>
	Richard Guenther  <rguenther@suse.de>

	PR debug/31899
	* dwarf2out.c (reference_to_unused): Disable sanity checking,
	be conservative instead.

	* g++.dg/debug/using3.C: New testcase.

Co-Authored-By: Richard Guenther <rguenther@suse.de>

From-SVN: r128978

gcc/ChangeLog

+2007-10-03  Doug Kwan  <dougkwan@google.com>
+	Richard Guenther  <rguenther@suse.de>
+
+	PR debug/31899
+	* dwarf2out.c (reference_to_unused): Disable sanity checking,
+	be conservative instead.
+
 2007-10-03  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	PR fortran/26682

gcc/dwarf2out.c

@@ -10344,9 +10344,12 @@ reference_to_unused (tree * tp, int * walk_subtrees,
     return *tp;
   else if (!flag_unit_at_a_time)
     return NULL_TREE;
+  /* ???  The C++ FE emits debug information for using decls, so
+     putting gcc_unreachable here falls over.  See PR31899.  For now
+     be conservative.  */
   else if (!cgraph_global_info_ready
 	   && (TREE_CODE (*tp) == VAR_DECL || TREE_CODE (*tp) == FUNCTION_DECL))
-    gcc_unreachable ();
+    return *tp;
   else if (DECL_P (*tp) && TREE_CODE (*tp) == VAR_DECL)
     {
       struct varpool_node *node = varpool_node (*tp);

gcc/testsuite/ChangeLog

+2007-10-03  Doug Kwan  <dougkwan@google.com>
+	Richard Guenther  <rguenther@suse.de>
+
+	PR debug/31899
+	* g++.dg/debug/using3.C: New testcase.
+
 2007-10-03  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libfortran/33253

gcc/testsuite/g++.dg/debug/using3.C

+// PR debug/31899
+
+namespace NS {
+  int x = 0;
+  int &ref = x;
+}
+
+using NS::ref;