diff --git a/CMakeLists.txt b/CMakeLists.txt
index b12e373df4..462590d222 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -695,52 +695,38 @@ else()
 	set(BUILD_SHARED_LIBS 1)
 endif()
 
-# Sigh: Have to use THIS_FLAG instead of ${F} for some reason
-foreach(THIS_FLAG ${C_FLAG_TESTS})
-	string( REGEX REPLACE "[^a-zA-Z0-9_]+" "_" F ${THIS_FLAG} )
-	set(${F} ${THIS_FLAG})
-	set(V C_${F}_VALID)
-	message(STATUS "Checking for c-compiler flag: ${THIS_FLAG}")
-	check_c_compiler_flag("${ADDED_CMAKE_C_FLAGS} ${${F}}" ${V})
-	if (${${V}})
-		set(ADDED_CMAKE_C_FLAGS "${ADDED_CMAKE_C_FLAGS} ${${F}}")
+function(test_compiler_flag _lang _this_flag _valid_flags_var)
+	string(MAKE_C_IDENTIFIER "${_lang}${_this_flag}_VALID" _flag_var)
+	set(_test_flags "${${_valid_flags_var}} ${_this_flag}")
+	if(_lang STREQUAL "C")
+		check_c_compiler_flag("${_test_flags}" ${_flag_var})
+	elseif(_lang STREQUAL "CXX")
+		check_cxx_compiler_flag("${_test_flags}" ${_flag_var})
+	else()
+		message(FATAL_ERROR "Language must be C or CXX")
 	endif()
+	if (${_flag_var})
+		set(${_valid_flags_var} "${_test_flags}" PARENT_SCOPE)
+	endif()
+endfunction()
+
+foreach(THIS_FLAG ${C_FLAG_TESTS})
+	test_compiler_flag(C ${THIS_FLAG} ADDED_CMAKE_C_FLAGS)
 endforeach()
 set(CMAKE_C_FLAGS "${ADDED_CMAKE_C_FLAGS} ${CMAKE_C_FLAGS}")
 
 foreach(THIS_FLAG ${CXX_FLAG_TESTS})
-	string( REGEX REPLACE "[^a-zA-Z0-9_]+" "_" F ${THIS_FLAG} )
-	set(${F} ${THIS_FLAG})
-	set(V CXX_${F}_VALID)
-	message(STATUS "Checking for c++-compiler flag: ${THIS_FLAG}")
-	check_cxx_compiler_flag("${ADDED_CMAKE_CXX_FLAGS} ${${F}}" ${V})
-	if (${${V}})
-		set(ADDED_CMAKE_CXX_FLAGS "${ADDED_CMAKE_CXX_FLAGS} ${${F}}")
-	endif()
+	test_compiler_flag(CXX ${THIS_FLAG} ADDED_CMAKE_CXX_FLAGS)
 endforeach()
 set(CMAKE_CXX_FLAGS "${ADDED_CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS}")
 
 foreach(THIS_FLAG ${C_WARN_TESTS})
-	string( REGEX REPLACE "[^a-zA-Z0-9_]+" "_" F ${THIS_FLAG} )
-	set(${F} ${THIS_FLAG})
-	set(V C_${F}_VALID)
-	message(STATUS "Checking for c-compiler flag: ${THIS_FLAG}")
-	check_c_compiler_flag("${C_FLAG_TESTS} ${${F}}" ${V})
-	if (${${V}})
-		set(ADDED_WARN_C_FLAGS "${ADDED_WARN_C_FLAGS} ${${F}}")
-	endif()
+	test_compiler_flag(C ${THIS_FLAG} ADDED_WARN_C_FLAGS)
 endforeach()
 set(CMAKE_C_FLAGS "${ADDED_WARN_C_FLAGS} ${CMAKE_C_FLAGS}")
 
 foreach(THIS_FLAG ${CXX_WARN_TESTS})
-	string( REGEX REPLACE "[^a-zA-Z0-9_]+" "_" F ${THIS_FLAG} )
-	set(${F} ${THIS_FLAG})
-	set(V CXX_${F}_VALID)
-	message(STATUS "Checking for c++-compiler flag: ${THIS_FLAG}")
-	check_cxx_compiler_flag("${CXX_FLAG_TESTS} ${${F}}" ${V})
-	if (${${V}})
-		set(ADDED_WARN_CXX_FLAGS "${ADDED_WARN_CXX_FLAGS} ${${F}}")
-	endif()
+	test_compiler_flag(CXX ${THIS_FLAG} ADDED_WARN_CXX_FLAGS)
 endforeach()
 set(CMAKE_CXX_FLAGS "${ADDED_WARN_CXX_FLAGS} ${CMAKE_CXX_FLAGS}")