1 files changed, 78 insertions, 0 deletions
diff --git a/src/catch2/benchmark/catch_optimizer.hpp b/src/catch2/benchmark/catch_optimizer.hpp
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+++ b/src/catch2/benchmark/catch_optimizer.hpp
@@ -0,0 +1,78 @@
+
+//              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.
+
+#ifndef CATCH_OPTIMIZER_HPP_INCLUDED
+#define CATCH_OPTIMIZER_HPP_INCLUDED
+
+#if defined(_MSC_VER) || defined(__IAR_SYSTEMS_ICC__)
+#   include <atomic> // atomic_thread_fence
+#endif
+
+#include <catch2/internal/catch_move_and_forward.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(_MSVC_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(_MSVC_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)...);
+        }
+    } // namespace Benchmark
+} // namespace Catch
+
+#endif // CATCH_OPTIMIZER_HPP_INCLUDED