1 files changed, 57 insertions, 0 deletions
diff --git a/libcxx/test/libcxx-03/algorithms/half_positive.pass.cpp b/libcxx/test/libcxx-03/algorithms/half_positive.pass.cpp
new file mode 100644
index 000000000000..292fcf356554
--- /dev/null
+++ b/libcxx/test/libcxx-03/algorithms/half_positive.pass.cpp
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <algorithm>
+
+// __half_positive divides an integer number by 2 as unsigned number for known types.
+// It can be an important optimization for lower bound, for example.
+
+#include <__cxx03/__algorithm/half_positive.h>
+#include <cassert>
+#include <cstddef>
+#include <limits>
+
+#include "test_macros.h"
+#include "user_defined_integral.h"
+
+namespace {
+
+template <class IntType, class UnderlyingType = IntType>
+TEST_CONSTEXPR bool test(IntType max_v = IntType(std::numeric_limits<UnderlyingType>::max())) {
+    return std::__half_positive(max_v) == max_v / 2;
+}
+
+}  // namespace
+
+int main(int, char**)
+{
+    {
+        assert(test<char>());
+        assert(test<int>());
+        assert(test<long>());
+        assert((test<UserDefinedIntegral<int>, int>()));
+        assert(test<std::size_t>());
+#if !defined(TEST_HAS_NO_INT128)
+        assert(test<__int128_t>());
+#endif // !defined(TEST_HAS_NO_INT128)
+    }
+
+#if TEST_STD_VER >= 11
+    {
+        static_assert(test<char>(), "");
+        static_assert(test<int>(), "");
+        static_assert(test<long>(), "");
+        static_assert(test<std::size_t>(), "");
+#if !defined(TEST_HAS_NO_INT128)
+        static_assert(test<__int128_t>(), "");
+#endif // !defined(TEST_HAS_NO_INT128)
+    }
+#endif // TEST_STD_VER >= 11
+
+  return 0;
+}