--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/warn/Wunused-var-34.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,27 @@
+// PR c++/85963
+// { dg-additional-options -Wall }
+
+template<typename T>
+struct foo {
+  T val, alpha;
+  foo() : val(0), alpha(0) {}
+};
+
+template<typename T>
+inline void bar(const foo<T>& A, const foo<T>& B, foo<T>& C) {
+  const bool use_alpha = true;
+  const T        alpha = use_alpha ? (A.alpha * B.alpha) : T(0);
+  
+  C.val   = A.val * B.val;
+  C.alpha = alpha;
+}
+
+
+int main() {
+  foo<double> A,B,C;
+  
+  bar(A,B,C);
+  
+  return 0;
+}
+