diff --git a/llvm/utils/TableGen/CodeEmitterGen.cpp b/llvm/utils/TableGen/CodeEmitterGen.cpp
--- a/llvm/utils/TableGen/CodeEmitterGen.cpp
+++ b/llvm/utils/TableGen/CodeEmitterGen.cpp
@@ -320,6 +320,8 @@
     Success &= addCodeToMergeInOperand(R, BI, std::string(RV.getName()), Case,
                                        BitOffsetCase, Target);
   }
+  BitOffsetCase += "      default:\n";
+  BitOffsetCase += "        break;\n";
   BitOffsetCase += "      }\n";
 
   if (!Success) {