From e8f45fad4071512a116dd983ae85e47f2d776f6f Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Fri, 18 Jan 2019 12:07:13 +0200
Subject: [PATCH] - workaround MSVC 2015 code generation issue, x64 only

With optimization turned on illegal instructions were generated for turbo CVAR handler function

https://forum.zdoom.org/viewtopic.php?t=63157
---
 src/g_game.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/g_game.cpp b/src/g_game.cpp
index da1430d84..2d463455f 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -222,6 +222,12 @@ EXTERN_CVAR (Int, team)
 
 CVAR (Bool, teamplay, false, CVAR_SERVERINFO)
 
+// Workaround for x64 code generation bug in MSVC 2015 
+// Optimized targets contain illegal instructions in the function below
+#if defined _M_X64 && _MSC_VER < 1910
+#pragma optimize("", off)
+#endif // _M_X64 && _MSC_VER < 1910
+
 // [RH] Allow turbo setting anytime during game
 CUSTOM_CVAR (Float, turbo, 100.f, CVAR_NOINITCALL)
 {
@@ -244,6 +250,10 @@ CUSTOM_CVAR (Float, turbo, 100.f, CVAR_NOINITCALL)
 	}
 }
 
+#if defined _M_X64 && _MSC_VER < 1910
+#pragma optimize("", on)
+#endif // _M_X64 && _MSC_VER < 1910
+
 CCMD (turnspeeds)
 {
 	if (argv.argc() == 1)