diff --git a/cmake/cxx_flag_overrides.cmake b/cmake/cxx_flag_overrides.cmake
index 9f4fc5d4ca..635489e3d3 100644
--- a/cmake/cxx_flag_overrides.cmake
+++ b/cmake/cxx_flag_overrides.cmake
@@ -4,10 +4,10 @@ if(WIN32)
     set(CMAKE_CXX_FLAGS_MINSIZEREL_INIT     "/MT /O1 /Ob1 /D NDEBUG")
     set(CMAKE_CXX_FLAGS_RELEASE_INIT        "/MT /O2 /Ob2 /D NDEBUG")
     set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "/MT /Zi /Od /Ob1 /D NDEBUG")
-  elseif(NOT MINGW)
+  elseif(MINGW)
     set(CMAKE_CXX_FLAGS_RELEASE_INIT "-D_MT -O3 -DNDEBUG")
-    set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-Wno-error=deprecated-declarations")
   else()
     set(CMAKE_CXX_FLAGS_RELEASE_INIT "-D_MT -O3 -DNDEBUG")
+    set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-Wno-error=deprecated-declarations")
   endif()
 endif()