Index: lib/Parse/ParseDeclCXX.cpp
===================================================================
--- lib/Parse/ParseDeclCXX.cpp
+++ lib/Parse/ParseDeclCXX.cpp
@@ -1103,6 +1103,11 @@
     return true;
   case tok::colon:
     return CouldBeBitfield;     // enum E { ... }   :         2;
+  // Microsoft compatibility
+  case tok::kw___cdecl:         // struct foo {...} __cdecl   x; // C4229
+    if (!getLangOpts().MicrosoftExt)
+      break;
+    // fall through
   // Type qualifiers
   case tok::kw_const:           // struct foo {...} const     x;
   case tok::kw_volatile:        // struct foo {...} volatile  x;
Index: test/Parser/ms-anachronism.c
===================================================================
--- /dev/null
+++ test/Parser/ms-anachronism.c
@@ -0,0 +1,3 @@
+// RUN: %clang_cc1 -triple i686-windows-msvc -fms-extensions -fsyntax-only -verify %s
+
+struct {} __cdecl s; // expected-warning {{'__cdecl' only applies to function types; type here is 'struct}}