--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/ext/attr-const.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,72 @@
+/*  PR c++/83871 - wrong code for attribute const and pure on distinct
+    template specializations
+    { dg-do compile }
+    { dg-options "-O1 -Wall -fdump-tree-optimized" } */
+
+int __attribute__ ((const)) fconst_none ();
+int fconst_none ();
+
+void func_const_none_failed ();
+
+void func_const_none ()
+{
+  int i0 = fconst_none ();
+  int i1 = fconst_none ();
+  if (i0 != i1)
+    func_const_none_failed ();
+
+  // { dg-final { scan-tree-dump-not "func_const_none_failed" "optimized" } }
+}
+
+
+int fnone_const ();
+int __attribute__ ((const)) fnone_const ();
+
+void func_none_const_failed ();
+
+void func_none_const ()
+{
+  int i0 = fnone_const ();
+  int i1 = fnone_const ();
+  if (i0 != i1)
+    func_none_const_failed ();
+
+  // { dg-final { scan-tree-dump-not "func_none_const_failed" "optimized" } }
+}
+
+template <class T>
+int __attribute__ ((const)) fconst_none (T);
+
+template <class T>
+int fconst_none (T);
+
+void templ_const_none_failed ();
+
+void template_const_none ()
+{
+  int i0 = fconst_none<int> (0);
+  int i1 = fconst_none<int> (0);
+  if (i0 != i1)
+    templ_const_none_failed ();
+
+  // { dg-final { scan-tree-dump-not "templ_const_none_failed" "optimized" } }
+}
+
+
+template <class T>
+int fnone_const (T);
+
+template <class T>
+int __attribute__ ((const)) fnone_const (T);
+
+void templ_none_const_failed ();
+
+void test_fnone_const ()
+{
+  int i0 = fnone_const<int> (0);
+  int i1 = fnone_const<int> (0);
+  if (i0 != i1)
+    templ_none_const_failed ();
+
+  // { dg-final { scan-tree-dump-not "templ_none_const_failed" "optimized" } }
+}