re PR sanitizer/66452 ([UBSAN] *.Lubsan_data0' defined but not used)

	PR sanitizer/66452
	* toplev.c (check_global_declaration): Don't warn about artificial
	decls.

	* g++.dg/ubsan/pr66452.C: New test.

From-SVN: r224216

gcc/ChangeLog

+2015-06-08  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/66452
+	* toplev.c (check_global_declaration): Don't warn about artificial
+	decls.
+
 2015-06-08  Tom de Vries  <tom@codesourcery.com>
 
 	PR tree-optimization/66436

gcc/testsuite/ChangeLog

+2015-06-08  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/66452
+	* g++.dg/ubsan/pr66452.C: New test.
+
 2015-06-08  Tom de Vries  <tom@codesourcery.com>
 
 	PR tree-optimization/66436

gcc/testsuite/g++.dg/ubsan/pr66452.C

+// PR sanitizer/66452
+// { dg-do compile }
+// { dg-options "-Wall -fsanitize=undefined" }
+
+class A {
+public:
+  A(int);
+};
+class B {
+  A m_fn1() const;
+};
+A B::m_fn1() const {
+  for (int i = 0;i;)
+    ;
+  return 0;
+}

gcc/toplev.c

@@ -534,6 +534,7 @@ check_global_declaration (tree decl)
 	 to handle multiple external decls in different scopes.  */
       && ! (DECL_NAME (decl) && TREE_USED (DECL_NAME (decl)))
       && ! DECL_EXTERNAL (decl)
+      && ! DECL_ARTIFICIAL (decl)
       && ! TREE_PUBLIC (decl)
       /* A volatile variable might be used in some non-obvious way.  */
       && ! TREE_THIS_VOLATILE (decl)