diff --git a/lib/TableGen/TGLexer.cpp b/lib/TableGen/TGLexer.cpp
index 0dc1c70136b..a993cfd9051 100644
--- a/lib/TableGen/TGLexer.cpp
+++ b/lib/TableGen/TGLexer.cpp
@@ -228,6 +228,7 @@ tgtok::TokKind TGLexer::LexIdentifier() {
   
   if (Len == 5 && !memcmp(IdentStart, "class", 5)) return tgtok::Class;
   if (Len == 3 && !memcmp(IdentStart, "def", 3)) return tgtok::Def;
+  if (Len == 8 && !memcmp(IdentStart, "multidef", 3)) return tgtok::MultiDef;
   if (Len == 4 && !memcmp(IdentStart, "defm", 4)) return tgtok::Defm;
   if (Len == 10 && !memcmp(IdentStart, "multiclass", 10))
     return tgtok::MultiClass;
diff --git a/lib/TableGen/TGLexer.h b/lib/TableGen/TGLexer.h
index 84d328b12d9..7e222875aa8 100644
--- a/lib/TableGen/TGLexer.h
+++ b/lib/TableGen/TGLexer.h
@@ -41,7 +41,7 @@ namespace tgtok {
     equal, question,    // = ?
     
     // Keywords.
-    Bit, Bits, Class, Code, Dag, Def, Defm, Field, In, Int, Let, List,
+    Bit, Bits, Class, Code, Dag, Def, MultiDef, Defm, Field, In, Int, Let, List,
     MultiClass, String,
     
     // !keywords.