diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 32353b51ee58..8e5f57d6d890 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -766,6 +766,7 @@ def MicrosoftConstInit : DiagGroup<"microsoft-const-init">;
 def MicrosoftVoidPseudoDtor : DiagGroup<"microsoft-void-pseudo-dtor">;
 def MicrosoftAnonTag : DiagGroup<"microsoft-anon-tag">;
 def MicrosoftCommentPaste : DiagGroup<"microsoft-comment-paste">;
+def MicrosoftEndOfFile : DiagGroup<"microsoft-end-of-file">;
 // Aliases.
 def : DiagGroup<"msvc-include", [MicrosoftInclude]>;
                 // -Wmsvc-include = -Wmicrosoft-include
@@ -780,7 +781,7 @@ def Microsoft : DiagGroup<"microsoft",
      MicrosoftRedeclareStatic, MicrosoftEnumForwardReference, MicrosoftGoto,
      MicrosoftFlexibleArray, MicrosoftExtraQualification, MicrosoftCast,
      MicrosoftConstInit, MicrosoftVoidPseudoDtor, MicrosoftAnonTag,
-     MicrosoftCommentPaste]>;
+     MicrosoftCommentPaste, MicrosoftEndOfFile]>;
 
 def ObjCNonUnifiedException : DiagGroup<"objc-nonunified-exceptions">;
 
diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
index 2ed40c0cdedd..bf86b7077cbb 100644
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -62,6 +62,9 @@ def ext_charize_microsoft : Extension<
 def ext_comment_paste_microsoft : Extension<
   "pasting two '/' tokens into a '//' comment token is a Microsoft extension">,
   InGroup<MicrosoftCommentPaste>;
+def ext_ctrl_z_eof_microsoft : Extension<
+  "treating Ctrl-Z as end-of-file is a Microsoft extension">,
+  InGroup<MicrosoftEndOfFile>;
 
 def ext_token_used : Extension<"extension used">,
   InGroup<DiagGroup<"language-extension-token">>;
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index 4872dee82456..27b0feb48270 100644
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -2960,8 +2960,11 @@ LexNextToken:
       
   case 26:  // DOS & CP/M EOF: "^Z".
     // If we're in Microsoft extensions mode, treat this as end of file.
-    if (LangOpts.MicrosoftExt)
+    if (LangOpts.MicrosoftExt) {
+      if (!isLexingRawMode())
+        Diag(CurPtr-1, diag::ext_ctrl_z_eof_microsoft);
       return LexEndOfFile(Result, CurPtr-1);
+    }
 
     // If Microsoft extensions are disabled, this is just random garbage.
     Kind = tok::unknown;
diff --git a/clang/test/Lexer/msdos-cpm-eof.c b/clang/test/Lexer/msdos-cpm-eof.c
index 3469b59d4089..274e6305a91e 100644
--- a/clang/test/Lexer/msdos-cpm-eof.c
+++ b/clang/test/Lexer/msdos-cpm-eof.c
@@ -1,8 +1,8 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -fms-extensions %s
-// expected-no-diagnostics
+// RUN: %clang_cc1 -fsyntax-only -verify -fms-extensions -Wmicrosoft %s
 
 int x; 
 
+// expected-warning@+1 {{treating Ctrl-Z as end-of-file is a Microsoft extension">,
 
 
 I am random garbage after ^Z