Index: llvm/trunk/utils/TableGen/InfoByHwMode.h
===================================================================
--- llvm/trunk/utils/TableGen/InfoByHwMode.h
+++ llvm/trunk/utils/TableGen/InfoByHwMode.h
@@ -129,7 +129,7 @@
   MVT getType(unsigned Mode) const { return get(Mode); }
   MVT &getOrCreateTypeForMode(unsigned Mode, MVT Type);
 
-  static std::string getMVTName(MVT T);
+  static StringRef getMVTName(MVT T);
   std::string getAsString() const;
   void dump() const;
 };
Index: llvm/trunk/utils/TableGen/InfoByHwMode.cpp
===================================================================
--- llvm/trunk/utils/TableGen/InfoByHwMode.cpp
+++ llvm/trunk/utils/TableGen/InfoByHwMode.cpp
@@ -70,10 +70,9 @@
   return Map.insert(std::make_pair(Mode, Type)).first->second;
 }
 
-std::string ValueTypeByHwMode::getMVTName(MVT T) {
-  std::string N = llvm::getEnumName(T.SimpleTy);
-  if (N.substr(0,5) == "MVT::")
-    N = N.substr(5);
+StringRef ValueTypeByHwMode::getMVTName(MVT T) {
+  StringRef N = llvm::getEnumName(T.SimpleTy);
+  N.consume_front("MVT::");
   return N;
 }
 
@@ -91,7 +90,7 @@
   for (unsigned i = 0, e = Pairs.size(); i != e; ++i) {
     const PairType *P = Pairs[i];
     str << '(' << getModeName(P->first)
-        << ':' << getMVTName(P->second) << ')';
+        << ':' << getMVTName(P->second).str() << ')';
     if (i != e-1)
       str << ',';
   }