1 files changed, 72 insertions, 0 deletions
diff --git a/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp b/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp
new file mode 100644
index 00000000000..65051af790d
--- /dev/null
+++ b/libcxx/test/std/atomics/atomics.flag/clear.pass.cpp
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads
+
+// <atomic>
+
+// struct atomic_flag
+
+// void clear(memory_order = memory_order_seq_cst);
+// void clear(memory_order = memory_order_seq_cst) volatile;
+
+#include <atomic>
+#include <cassert>
+
+int main()
+{
+    {
+        std::atomic_flag f;
+        f.test_and_set();
+        f.clear();
+        assert(f.test_and_set() == 0);
+    }
+    {
+        std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_relaxed);
+        assert(f.test_and_set() == 0);
+    }
+    {
+        std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_release);
+        assert(f.test_and_set() == 0);
+    }
+    {
+        std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_seq_cst);
+        assert(f.test_and_set() == 0);
+    }
+    {
+        volatile std::atomic_flag f;
+        f.test_and_set();
+        f.clear();
+        assert(f.test_and_set() == 0);
+    }
+    {
+        volatile std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_relaxed);
+        assert(f.test_and_set() == 0);
+    }
+    {
+        volatile std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_release);
+        assert(f.test_and_set() == 0);
+    }
+    {
+        volatile std::atomic_flag f;
+        f.test_and_set();
+        f.clear(std::memory_order_seq_cst);
+        assert(f.test_and_set() == 0);
+    }
+}