PR c++/71630 - extern variable template

	* pt.c (instantiate_decl): Fix pattern_defined for namespace scope
	variable templates.

From-SVN: r238622

gcc/cp/ChangeLog

 2016-07-21  Jason Merrill  <jason@redhat.com>
 
+	PR c++/71630
+	* pt.c (instantiate_decl): Fix pattern_defined for namespace scope
+	variable templates.
+
 	PR c++/71913
 	* call.c (unsafe_copy_elision_p): It's OK to elide when
 	initializing an unknown object.

gcc/cp/pt.c

@@ -21853,7 +21853,10 @@ instantiate_decl (tree d, int defer_ok,
   else
     {
       deleted_p = false;
-      pattern_defined = ! DECL_IN_AGGR_P (code_pattern);
+      if (DECL_CLASS_SCOPE_P (code_pattern))
+	pattern_defined = ! DECL_IN_AGGR_P (code_pattern);
+      else
+	pattern_defined = ! DECL_EXTERNAL (code_pattern);
     }
 
   /* We may be in the middle of deferred access check.  Disable it now.  */

gcc/testsuite/g++.dg/cpp1y/var-templ53.C

+// PR c++/71630
+// { dg-do compile { target c++14 } }
+
+template <class T>
+extern T pi;
+
+int main()
+{
+  return pi<int>;
+}