--- a/gcc/c-family/c-cppbuiltin.cc
+++ b/gcc/c-family/c-cppbuiltin.cc
@@ -1513,7 +1513,7 @@ c_cpp_builtins (cpp_reader *pfile)
 #if !defined(ACCEL_COMPILER)
   /* Fortify Source enabled by default for optimization levels > 0 */
   if (optimize)
-    builtin_define_with_int_value ("_FORTIFY_SOURCE", 2);
+    builtin_define_with_int_value ("_FORTIFY_SOURCE", 3);
 #endif

   /* Misc.  */