Subzero: Remove IceString.

src/IceRegistersARM32.h

 //===- subzero/src/IceRegistersARM32.h - Register information ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 189 matching lines @@
 static inline bool isEncodedQReg(RegNumT RegNum) {
   RegNum.assertIsValid();
   return RegTable[RegNum].IsVec128;
 }
 
 static inline QRegister getEncodedQReg(RegNumT RegNum) {
   assert(isEncodedQReg(RegNum));
   return QRegister(RegTable[RegNum].Encoding);
 }
 
-static inline IceString getRegName(RegNumT RegNum) {
+static inline const char *getRegName(RegNumT RegNum) {
   RegNum.assertIsValid();
   return RegTable[RegNum].Name;
 }
 
 // Extend enum RegClass with ARM32-specific register classes.
 enum RegClassARM32 : uint8_t {
   RCARM32_QtoS = RC_Target, // Denotes Q registers that are aliased by S
                             // registers.
   RCARM32_NUM
 };
 
 } // end of namespace RegARM32
 } // end of namespace ARM32
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEREGISTERSARM32_H