commit e3359de1378a74fd049bcb3e737feefaa359a8f6
Author: Jason Merrill <jason@redhat.com>
Date: Mon Jun 11 16:54:24 2018 -0400
PR c++/85963 - -Wunused-but-set with ?: in template.
* pt.c (tsubst_copy_and_build) [COND_EXPR]: Call mark_rvalue_use.
@@ -18511,6 +18511,7 @@ tsubst_copy_and_build (tree t,
case COND_EXPR:
{
tree cond = RECUR (TREE_OPERAND (t, 0));
+ cond = mark_rvalue_use (cond);
tree folded_cond = fold_non_dependent_expr (cond);
tree exp1, exp2;
new file mode 100644
@@ -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;
+}
+