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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: c++03, c++11, c++14, c++17
// XFAIL: !has-64-bit-atomics
// XFAIL: !has-1024-bit-atomics
// MSVC warning C4310: cast truncates constant value
// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4310
// bool compare_exchange_weak(T&, T, memory_order, memory_order) const noexcept;
// bool compare_exchange_weak(T&, T, memory_order = memory_order::seq_cst) const noexcept;
#include <atomic>
#include <concepts>
#include <cassert>
#include <type_traits>
#include "atomic_helpers.h"
#include "test_helper.h"
#include "test_macros.h"
template <typename T>
struct TestCompareExchangeWeak {
void operator()() const {
{
T x(T(1));
std::atomic_ref<T> const a(x);
T t(T(1));
std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(2));
assert(y == true);
assert(a == T(2));
assert(t == T(1));
y = a.compare_exchange_weak(t, T(3));
assert(y == false);
assert(a == T(2));
assert(t == T(2));
ASSERT_NOEXCEPT(a.compare_exchange_weak(t, T(2)));
}
{
T x(T(1));
std::atomic_ref<T> const a(x);
T t(T(1));
std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(2), std::memory_order_seq_cst);
assert(y == true);
assert(a == T(2));
assert(t == T(1));
y = a.compare_exchange_weak(t, T(3), std::memory_order_seq_cst);
assert(y == false);
assert(a == T(2));
assert(t == T(2));
ASSERT_NOEXCEPT(a.compare_exchange_weak(t, T(2), std::memory_order_seq_cst));
}
{
T x(T(1));
std::atomic_ref<T> const a(x);
T t(T(1));
std::same_as<bool> decltype(auto) y =
a.compare_exchange_weak(t, T(2), std::memory_order_release, std::memory_order_relaxed);
assert(y == true);
assert(a == T(2));
assert(t == T(1));
y = a.compare_exchange_weak(t, T(3), std::memory_order_release, std::memory_order_relaxed);
assert(y == false);
assert(a == T(2));
assert(t == T(2));
ASSERT_NOEXCEPT(a.compare_exchange_weak(t, T(2), std::memory_order_release, std::memory_order_relaxed));
}
// success memory_order::release
{
auto store = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::release, std::memory_order::relaxed)) {
}
};
auto load = [](std::atomic_ref<T> const& x) { return x.load(std::memory_order::acquire); };
test_acquire_release<T>(store, load);
auto store_one_arg = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::release)) {
}
};
test_acquire_release<T>(store_one_arg, load);
}
// success memory_order::acquire
{
auto store = [](std::atomic_ref<T> const& x, T, T new_val) { x.store(new_val, std::memory_order::release); };
auto load = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::acquire, std::memory_order::relaxed)) {
}
return val;
};
test_acquire_release<T>(store, load);
auto load_one_arg = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::acquire)) {
}
return val;
};
test_acquire_release<T>(store, load_one_arg);
}
// success memory_order::acq_rel
{
auto store = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::acq_rel, std::memory_order::relaxed)) {
}
};
auto load = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::acq_rel, std::memory_order::relaxed)) {
}
return val;
};
test_acquire_release<T>(store, load);
auto store_one_arg = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::acq_rel)) {
}
};
auto load_one_arg = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::acq_rel)) {
}
return val;
};
test_acquire_release<T>(store_one_arg, load_one_arg);
}
// success memory_order::seq_cst
{
auto store = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::seq_cst, std::memory_order::relaxed)) {
}
};
auto load = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::seq_cst, std::memory_order::relaxed)) {
}
return val;
};
test_seq_cst<T>(store, load);
auto store_one_arg = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
// could fail spuriously, so put it in a loop
while (!x.compare_exchange_weak(old_val, new_val, std::memory_order::seq_cst)) {
}
};
auto load_one_arg = [](std::atomic_ref<T> const& x) {
auto val = x.load(std::memory_order::relaxed);
while (!x.compare_exchange_weak(val, val, std::memory_order::seq_cst)) {
}
return val;
};
test_seq_cst<T>(store_one_arg, load_one_arg);
}
// failure memory_order::acquire
{
auto store = [](std::atomic_ref<T> const& x, T, T new_val) { x.store(new_val, std::memory_order::release); };
auto load = [](std::atomic_ref<T> const& x) {
auto result = x.load(std::memory_order::relaxed);
T unexpected(T(255));
bool r =
x.compare_exchange_weak(unexpected, unexpected, std::memory_order::relaxed, std::memory_order::acquire);
assert(!r);
return result;
};
test_acquire_release<T>(store, load);
auto load_one_arg = [](std::atomic_ref<T> const& x) {
auto result = x.load(std::memory_order::relaxed);
T unexpected(T(255));
bool r = x.compare_exchange_weak(unexpected, unexpected, std::memory_order::acquire);
assert(!r);
return result;
};
test_acquire_release<T>(store, load_one_arg);
// acq_rel replaced by acquire
auto load_one_arg_acq_rel = [](std::atomic_ref<T> const& x) {
auto result = x.load(std::memory_order::relaxed);
T unexpected(T(255));
bool r = x.compare_exchange_weak(unexpected, unexpected, std::memory_order::acq_rel);
assert(!r);
return result;
};
test_acquire_release<T>(store, load_one_arg_acq_rel);
}
// failure memory_order::seq_cst
{
auto store = [](std::atomic_ref<T> const& x, T, T new_val) { x.store(new_val, std::memory_order::seq_cst); };
auto load = [](std::atomic_ref<T> const& x) {
auto result = x.load(std::memory_order::relaxed);
T unexpected(T(255));
bool r =
x.compare_exchange_weak(unexpected, unexpected, std::memory_order::relaxed, std::memory_order::seq_cst);
assert(!r);
return result;
};
test_seq_cst<T>(store, load);
}
}
};
int main(int, char**) {
TestEachAtomicType<TestCompareExchangeWeak>()();
return 0;
}
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