diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 248ce4f72b2..27529a86b74 100644
--- a/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/utils/TableGen/AsmMatcherEmitter.cpp
@@ -766,6 +766,7 @@ static std::string getEnumNameForToken(StringRef Str) {
     case '*': Res += "_STAR_"; break;
     case '%': Res += "_PCT_"; break;
     case ':': Res += "_COLON_"; break;
+    case '!': Res += "_EXCLAIM_"; break;
     default:
       if (isalnum(*it))
         Res += *it;