diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 537390a..cc94488 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3390,6 +3390,8 @@
                     options::OPT_fmodules_validate_once_per_build_session);
   }
 
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_validate_system_headers);
+
   // -faccess-control is default.
   if (Args.hasFlag(options::OPT_fno_access_control,
                    options::OPT_faccess_control,