Added a little safeguard against GCC optimizer bug.

CMakeLists.txt

@@ -7,7 +7,6 @@ if ( EXISTS /ACG/acgdev/gcc-4.9-x86_64/qt-5.6.0/5.6/gcc_64/ )
   set (QT5_INSTALL_PATH /ACG/acgdev/gcc-4.9-x86_64/qt-5.6.0/5.6/gcc_64/ CACHE PATH "Qt5 install path set for ACG environment" )
 endif()
 
-
 if ( WIN32 )
   # This is the base directory for windows library search used in the finders we shipp.
   set(CMAKE_WINDOWS_LIBS_DIR "c:/libs" CACHE STRING "Default Library search dir on windows." )
@@ -28,6 +27,14 @@ endif()
 
 project (OpenFlipper)
 
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+	if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "6.0" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "4.9" OR CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL "4.9")
+		message(WARNING "Your version of GCC contains an optimizer bug. Please verify that you do not use -O3!")
+		string(REPLACE "-O3" "-O2" CMAKE_CXX_FLAGS_RELEASE_NEW "${CMAKE_CXX_FLAGS_RELEASE}")
+		set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE_NEW}" CACHE STRING "" FORCE)
+	endif()
+endif()
+
 # add our macro directory to cmake search path
 set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake)