diff --git a/Modules/CMakeSwiftInformation.cmake b/Modules/CMakeSwiftInformation.cmake
index ecad1d51e8..16726d2d27 100644
--- a/Modules/CMakeSwiftInformation.cmake
+++ b/Modules/CMakeSwiftInformation.cmake
@@ -65,7 +65,7 @@ set(CMAKE_Swift_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDLL -libc MD)
 set(CMAKE_Swift_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDebug -libc MTd)
 set(CMAKE_Swift_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDebugDLL -libc MDd)
 
-set(CMAKE_Swift_FLAGS_DEBUG_INIT "-g")
+set(CMAKE_Swift_FLAGS_DEBUG_INIT "-Onone -g")
 set(CMAKE_Swift_FLAGS_RELEASE_INIT "-O")
 set(CMAKE_Swift_FLAGS_RELWITHDEBINFO_INIT "-O -g")
 set(CMAKE_Swift_FLAGS_MINSIZEREL_INIT "-Osize")