Index: include/clang/Driver/CLCompatOptions.td
===================================================================
--- include/clang/Driver/CLCompatOptions.td
+++ include/clang/Driver/CLCompatOptions.td
@@ -77,6 +77,10 @@
 def _SLASH_GR_ : CLFlag<"GR-">, HelpText<"Disable emission of RTTI data">;
 def _SLASH_GF_ : CLFlag<"GF-">, HelpText<"Disable string pooling">,
   Alias<fwritable_strings>;
+def _SLASH_GS : CLFlag<"GS">, HelpText<"Enable buffer security check">,
+  Alias<fstack_protector_strong>;
+def _SLASH_GS_ : CLFlag<"GS-">, HelpText<"Disable buffer security check">,
+  Alias<fno_stack_protector>;
 def _SLASH_Gs : CLJoined<"Gs">, HelpText<"Set stack probe size">,
   Alias<mstack_probe_size>;
 def _SLASH_Gy : CLFlag<"Gy">, HelpText<"Put each function in its own section">,
@@ -281,7 +285,6 @@
 def _SLASH_FS : CLIgnoredFlag<"FS">, HelpText<"Force synchronous PDB writes">;
 def _SLASH_Gd : CLIgnoredFlag<"Gd">;
 def _SLASH_GF : CLIgnoredFlag<"GF">;
-def _SLASH_GS_ : CLIgnoredFlag<"GS-">;
 def _SLASH_kernel_ : CLIgnoredFlag<"kernel-">;
 def _SLASH_nologo : CLIgnoredFlag<"nologo">;
 def _SLASH_Ob1 : CLIgnoredFlag<"Ob1">;
@@ -325,7 +328,6 @@
 def _SLASH_Gm : CLFlag<"Gm">;
 def _SLASH_Gm_ : CLFlag<"Gm-">;
 def _SLASH_Gr : CLFlag<"Gr">;
-def _SLASH_GS : CLFlag<"GS">;
 def _SLASH_GT : CLFlag<"GT">;
 def _SLASH_Guard : CLJoined<"guard:">;
 def _SLASH_Gv : CLFlag<"Gv">;