re PR middle-end/27657 (bogus undefined reference error to static var with -g and -O)

2007-01-30  Richard Guenther  <rguenther@suse.de>

	PR middle-end/27657
	* dwarf2out.c (reference_to_unused): Query varpool if the
	variable was output.

	* g++.dg/debug/pr27657.C: New testcase.

From-SVN: r121335

gcc/ChangeLog

 2007-01-30  Richard Guenther  <rguenther@suse.de>
 
+	PR middle-end/27657
+	* dwarf2out.c (reference_to_unused): Query varpool if the
+	variable was output.
+
+2007-01-30  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/30313
 	* passes.c (execute_one_pass): Reset in_gimple_form to not
 	confuse non-unit-at-a-time mode.

gcc/dwarf2out.c

@@ -10045,8 +10045,14 @@ reference_to_unused (tree * tp, int * walk_subtrees,
   if (DECL_P (*tp) && ! TREE_PUBLIC (*tp) && ! TREE_USED (*tp)
       && ! TREE_ASM_WRITTEN (*tp))
     return *tp;
-  else
-    return NULL_TREE;
+  else if (DECL_P (*tp) && TREE_CODE (*tp) != FUNCTION_DECL)
+    {
+      struct varpool_node *node = varpool_node (*tp);
+      if (!node->needed)
+	return *tp;
+    }
+
+  return NULL_TREE;
 }
 
 /* Generate an RTL constant from a decl initializer INIT with decl type TYPE,

gcc/testsuite/ChangeLog

 2007-01-30  Richard Guenther  <rguenther@suse.de>
 
+	PR middle-end/27657
+	* g++.dg/debug/pr27657.C: New testcase.
+
+2007-01-30  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/30313
 	* gcc.dg/torture/pr30313.c: New testcase.
 

gcc/testsuite/g++.dg/debug/pr27657.C

+/* { dg-do link } */
+
+const char s[] = "";
+const char *const p = s;
+
+int main()
+{
+  return 0;
+}