vendor/libc++/libc++-release_370-r246257

1 files changed, 43 insertions, 0 deletions

diff --git a/test/std/atomics/atomics.general/replace_failure_order.pass.cpp b/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
new file mode 100644
index 0000000000000..cd0683d6887d5
--- /dev/null
+++ b/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// This test verifies behavior specified by [atomics.types.operations.req]/21:
+//
+//     When only one memory_order argument is supplied, the value of success is
+//     order, and the value of failure is order except that a value of
+//     memory_order_acq_rel shall be replaced by the value memory_order_acquire
+//     and a value of memory_order_release shall be replaced by the value
+//     memory_order_relaxed.
+//
+// Clang's atomic intrinsics do this for us, but GCC's do not. We don't actually
+// have visibility to see what these memory orders are lowered to, but we can at
+// least check that they are lowered at all (otherwise there is a compile
+// failure with GCC).
+
+#include <atomic>
+
+int main() {
+    std::atomic<int> i;
+    volatile std::atomic<int> v;
+    int exp = 0;
+
+    i.compare_exchange_weak(exp, 0, std::memory_order_acq_rel);
+    i.compare_exchange_weak(exp, 0, std::memory_order_release);
+    i.compare_exchange_strong(exp, 0, std::memory_order_acq_rel);
+    i.compare_exchange_strong(exp, 0, std::memory_order_release);
+
+    v.compare_exchange_weak(exp, 0, std::memory_order_acq_rel);
+    v.compare_exchange_weak(exp, 0, std::memory_order_release);
+    v.compare_exchange_strong(exp, 0, std::memory_order_acq_rel);
+    v.compare_exchange_strong(exp, 0, std::memory_order_release);
+
+    return 0;
+}