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// Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)
// SPDX-License-Identifier: BSL-1.0
// Adapted from donated nonius code.
#pragma once
#if defined(_MSC_VER) || defined(__IAR_SYSTEMS_ICC__)
# include <atomic> // atomic_thread_fence
#endif
#include <Progmasoft/Catch3/Internal/MoveAndForward.hpp>
#include <type_traits>
namespace Catch {
namespace Benchmark {
#if defined(__GNUC__) || defined(__clang__)
template <typename T>
inline void keep_memory(T* p) {
asm volatile("" : : "g"(p) : "memory");
}
inline void keep_memory() {
asm volatile("" : : : "memory");
}
namespace Detail {
inline void optimizer_barrier() { keep_memory(); }
} // namespace Detail
#elif defined(_MSC_VER) || defined(__IAR_SYSTEMS_ICC__)
#if defined(_MSC_VER)
#pragma optimize("", off)
#elif defined(__IAR_SYSTEMS_ICC__)
// For IAR the pragma only affects the following function
#pragma optimize=disable
#endif
template <typename T>
inline void keep_memory(T* p) {
// thanks @milleniumbug
*reinterpret_cast<char volatile*>(p) = *reinterpret_cast<char const volatile*>(p);
}
// TODO equivalent keep_memory()
#if defined(_MSC_VER)
#pragma optimize("", on)
#endif
namespace Detail {
inline void optimizer_barrier() {
std::atomic_thread_fence(std::memory_order_seq_cst);
}
} // namespace Detail
#endif
template <typename T>
inline void deoptimize_value(T&& x) {
keep_memory(&x);
}
template <typename Fn, typename... Args>
inline auto invoke_deoptimized(Fn&& fn, Args&&... args) -> std::enable_if_t<!std::is_same<void, decltype(fn(args...))>::value> {
deoptimize_value(CATCH_FORWARD(fn) (CATCH_FORWARD(args)...));
}
template <typename Fn, typename... Args>
inline auto invoke_deoptimized(Fn&& fn, Args&&... args) -> std::enable_if_t<std::is_same<void, decltype(fn(args...))>::value> {
CATCH_FORWARD((fn)) (CATCH_FORWARD(args)...);
// In the non-void case, we pass the result through `deoptimize_value`
// to force the compiler to keep it. We have no return value here,
// but add an optimizer barrier (ideally a memory clobber) to force
// the _side effects_ of the loop be visible (e.g. writes to globals).
// Note that writes to benchmark-locals can be optimized away, as
// we would expect in normal code.
Detail::optimizer_barrier();
}
} // namespace Benchmark
} // namespace Catch
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