diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef09142..3eb6d73 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -194,8 +194,12 @@ else()
             string(REGEX REPLACE ".*march=[ \t]*([^ \n]*)[ \n].*" "\\1"
                 GNUCC_ARCH "${_GCC_OUTPUT}")
 
-            # test the parsed flag
-            set (EXEC_ARGS ${CC_ARG1} -E - -mtune=${GNUCC_ARCH})
+	# test the parsed flag
+	if (!GNUCC_ARCH EQUAL NULL)
+		set (EXEC_ARGS ${CC_ARG1} -E - -mtune=${GNUCC_ARCH})
+	else ()
+		set (EXEC_ARGS ${CC_ARG1} -E - -mtune=native)
+	endif()
             execute_process(COMMAND ${CMAKE_C_COMPILER} ${EXEC_ARGS}
                 OUTPUT_QUIET ERROR_QUIET
                 INPUT_FILE /dev/null
