1 files changed, 16 insertions, 1 deletions
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
index 260e5edece5..bce1095f2ea 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.count/count.pass.cpp
@@ -11,14 +11,25 @@
 
 // template<InputIterator Iter, class T>
 //   requires HasEqualTo<Iter::value_type, T>
-//   Iter::difference_type
+//   constexpr Iter::difference_type   // constexpr after C++17
 //   count(Iter first, Iter last, const T& value);
 
 #include <algorithm>
 #include <cassert>
 
+#include "test_macros.h"
 #include "test_iterators.h"
 
+#if TEST_STD_VER > 17
+TEST_CONSTEXPR bool test_constexpr() {
+    int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
+    int ib[] = {1, 2, 3, 4, 5, 6};
+    return    (std::count(std::begin(ia), std::end(ia), 2) == 3)
+           && (std::count(std::begin(ib), std::end(ib), 9) == 0)
+           ;
+    }
+#endif
+
 int main()
 {
     int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
@@ -29,4 +40,8 @@ int main()
                       input_iterator<const int*>(ia + sa), 7) == 0);
     assert(std::count(input_iterator<const int*>(ia),
                       input_iterator<const int*>(ia), 2) == 0);
+
+#if TEST_STD_VER > 17
+    static_assert(test_constexpr());
+#endif
 }