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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
// integral-type fetch_sub(integral-type, memory_order = memory_order::seq_cst) const noexcept;
// floating-point-type fetch_sub(floating-point-type, memory_order = memory_order::seq_cst) const noexcept;
// T* fetch_sub(difference_type, memory_order = memory_order::seq_cst) const noexcept;
#include <atomic>
#include <cassert>
#include <concepts>
#include <type_traits>
#include "atomic_helpers.h"
#include "test_helper.h"
#include "test_macros.h"
template <typename T>
concept has_fetch_sub = requires {
std::declval<T const>().fetch_sub(std::declval<T>());
std::declval<T const>().fetch_sub(std::declval<T>(), std::declval<std::memory_order>());
};
template <typename T>
struct TestDoesNotHaveFetchSub {
void operator()() const { static_assert(!has_fetch_sub<std::atomic_ref<T>>); }
};
template <typename T>
struct TestFetchSub {
void operator()() const {
if constexpr (std::is_arithmetic_v<T>) {
T x(T(7));
std::atomic_ref<T> const a(x);
{
std::same_as<T> decltype(auto) y = a.fetch_sub(T(4));
assert(y == T(7));
assert(x == T(3));
ASSERT_NOEXCEPT(a.fetch_sub(T(0)));
}
{
std::same_as<T> decltype(auto) y = a.fetch_sub(T(2), std::memory_order_relaxed);
assert(y == T(3));
assert(x == T(1));
ASSERT_NOEXCEPT(a.fetch_sub(T(0), std::memory_order_relaxed));
}
} else if constexpr (std::is_pointer_v<T>) {
using U = std::remove_pointer_t<T>;
U t[9] = {};
T p{&t[7]};
std::atomic_ref<T> const a(p);
{
std::same_as<T> decltype(auto) y = a.fetch_sub(4);
assert(y == &t[7]);
assert(a == &t[3]);
ASSERT_NOEXCEPT(a.fetch_sub(0));
}
{
std::same_as<T> decltype(auto) y = a.fetch_sub(2, std::memory_order_relaxed);
assert(y == &t[3]);
assert(a == &t[1]);
ASSERT_NOEXCEPT(a.fetch_sub(0, std::memory_order_relaxed));
}
} else {
static_assert(std::is_void_v<T>);
}
// memory_order::release
{
auto fetch_sub = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
x.fetch_sub(old_val - new_val, std::memory_order::release);
};
auto load = [](std::atomic_ref<T> const& x) { return x.load(std::memory_order::acquire); };
test_acquire_release<T>(fetch_sub, load);
}
// memory_order::seq_cst
{
auto fetch_sub_no_arg = [](std::atomic_ref<T> const& x, T old_val, T new_val) { x.fetch_sub(old_val - new_val); };
auto fetch_sub_with_order = [](std::atomic_ref<T> const& x, T old_val, T new_val) {
x.fetch_sub(old_val - new_val, std::memory_order::seq_cst);
};
auto load = [](std::atomic_ref<T> const& x) { return x.load(); };
test_seq_cst<T>(fetch_sub_no_arg, load);
test_seq_cst<T>(fetch_sub_with_order, load);
}
}
};
int main(int, char**) {
TestEachIntegralType<TestFetchSub>()();
TestFetchSub<float>()();
TestFetchSub<double>()();
TestEachPointerType<TestFetchSub>()();
TestDoesNotHaveFetchSub<bool>()();
TestDoesNotHaveFetchSub<UserAtomicType>()();
TestDoesNotHaveFetchSub<LargeUserAtomicType>()();
return 0;
}
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