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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// 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(int, char**) {
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;
}
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