imm: compiler bug: MSVC 19.12 with /permissive- flag doesn't support fold expressions

src/common/math_util.h

@@ -0,0 +1,28 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2018 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#pragma once
+
+#include <utility>
+
+namespace Dynarmic {
+namespace Common {
+
+/**
+ * This function is a workaround for a bug in MSVC 19.12 where fold expressions
+ * do not work when the /permissive- flag is enabled.
+ */
+template<typename T, typename... Ts>
+constexpr T Sum(T first, Ts ...rest) {
+    if constexpr (sizeof...(rest) == 0) {
+        return first;
+    } else {
+        return first + Sum(std::forward<Ts>(rest)...);
+    }
+}
+
+} // namespace Common
+} // namespace Dynarmic