1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // This test verifies behavior specified by [atomics.types.operations.req]/21:
10 //
11 // When only one memory_order argument is supplied, the value of success is
12 // order, and the value of failure is order except that a value of
13 // memory_order_acq_rel shall be replaced by the value memory_order_acquire
14 // and a value of memory_order_release shall be replaced by the value
15 // memory_order_relaxed.
16 //
17 // Clang's atomic intrinsics do this for us, but GCC's do not. We don't actually
18 // have visibility to see what these memory orders are lowered to, but we can at
19 // least check that they are lowered at all (otherwise there is a compile
20 // failure with GCC).
21
22 #include <atomic>
23
24 #include "test_macros.h"
25
main(int,char **)26 int main(int, char**) {
27 std::atomic<int> i;
28 volatile std::atomic<int> v;
29 int exp = 0;
30
31 (void) i.compare_exchange_weak(exp, 0, std::memory_order_acq_rel);
32 (void) i.compare_exchange_weak(exp, 0, std::memory_order_release);
33 i.compare_exchange_strong(exp, 0, std::memory_order_acq_rel);
34 i.compare_exchange_strong(exp, 0, std::memory_order_release);
35
36 (void) v.compare_exchange_weak(exp, 0, std::memory_order_acq_rel);
37 (void) v.compare_exchange_weak(exp, 0, std::memory_order_release);
38 v.compare_exchange_strong(exp, 0, std::memory_order_acq_rel);
39 v.compare_exchange_strong(exp, 0, std::memory_order_release);
40
41 return 0;
42 }
43