diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index 097a030..3160e96 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -177,6 +177,8 @@
   HelpText<"Omit frame pointer setup for leaf functions.">;
 def msoft_float : Flag<"-msoft-float">,
   HelpText<"Use software floating point">;
+def mregparm : Separate<"-mregparm">,
+  HelpText<"Limit the number of registers available for integer arguments">;
 def mrelax_all : Flag<"-mrelax-all">,
   HelpText<"Relax all machine instructions">;
 def mrelocation_model : Separate<"-mrelocation-model">,