Index: llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp
+++ llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp
@@ -176,7 +176,7 @@
   const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
   for (unsigned I = 1, E = TRI->getNumSubRegIndices(); I < E; ++I)
     Names2SubRegIndices.insert(
-        std::make_pair(StringRef(TRI->getSubRegIndexName(I)).lower(), I));
+        std::make_pair(TRI->getSubRegIndexName(I), I));
 }
 
 unsigned PerTargetMIParsingState::getSubRegIndex(StringRef Name) {