diff --git a/include/llvm/MC/MCAsmLexer.h b/include/llvm/MC/MCAsmLexer.h
index 43bbfd2b458..a1d67b1861a 100644
--- a/include/llvm/MC/MCAsmLexer.h
+++ b/include/llvm/MC/MCAsmLexer.h
@@ -27,7 +27,6 @@ struct AsmToken {
 
     // String values.
     Identifier,
-    Register,
     String,
     
     // Integer values.
diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index d06350b8058..d102b371d4a 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -230,20 +230,23 @@ struct X86Operand {
 
 
 bool X86ATTAsmParser::ParseRegister(X86Operand &Op) {
+  const AsmToken &TokPercent = getLexer().getTok();
+  assert(TokPercent.is(AsmToken::Percent) && "Invalid token kind!");
+  getLexer().Lex(); // Eat percent token.
+
   const AsmToken &Tok = getLexer().getTok();
-  assert(Tok.is(AsmToken::Register) && "Invalid token kind!");
+  assert(TokPercent.is(AsmToken::Identifier) && "Invalid token kind!");
 
   // FIXME: Validate register for the current architecture; we have to do
   // validation later, so maybe there is no need for this here.
   unsigned RegNo;
-  assert(Tok.getString().startswith("%") && "Invalid register name!");
 
-  RegNo = MatchRegisterName(Tok.getString().substr(1));
+  RegNo = MatchRegisterName(Tok.getString());
   if (RegNo == 0)
     return Error(Tok.getLoc(), "invalid register name");
 
   Op = X86Operand::CreateReg(RegNo);
-  getLexer().Lex(); // Eat register token.
+  getLexer().Lex(); // Eat identifier token.
 
   return false;
 }
@@ -252,7 +255,7 @@ bool X86ATTAsmParser::ParseOperand(X86Operand &Op) {
   switch (getLexer().getKind()) {
   default:
     return ParseMemOperand(Op);
-  case AsmToken::Register:
+  case AsmToken::Percent:
     // FIXME: if a segment register, this could either be just the seg reg, or
     // the start of a memory operand.
     return ParseRegister(Op);
@@ -299,7 +302,7 @@ bool X86ATTAsmParser::ParseMemOperand(X86Operand &Op) {
     // so we have to eat the ( to see beyond it.
     getLexer().Lex(); // Eat the '('.
     
-    if (getLexer().is(AsmToken::Register) || getLexer().is(AsmToken::Comma)) {
+    if (getLexer().is(AsmToken::Percent) || getLexer().is(AsmToken::Comma)) {
       // Nothing to do here, fall into the code below with the '(' part of the
       // memory operand consumed.
     } else {
@@ -327,7 +330,7 @@ bool X86ATTAsmParser::ParseMemOperand(X86Operand &Op) {
   // the rest of the memory operand.
   unsigned BaseReg = 0, IndexReg = 0, Scale = 1;
   
-  if (getLexer().is(AsmToken::Register)) {
+  if (getLexer().is(AsmToken::Percent)) {
     if (ParseRegister(Op))
       return true;
     BaseReg = Op.getReg();
@@ -342,7 +345,7 @@ bool X86ATTAsmParser::ParseMemOperand(X86Operand &Op) {
     //
     // Not that even though it would be completely consistent to support syntax
     // like "1(%eax,,1)", the assembler doesn't.
-    if (getLexer().is(AsmToken::Register)) {
+    if (getLexer().is(AsmToken::Percent)) {
       if (ParseRegister(Op))
         return true;
       IndexReg = Op.getReg();
diff --git a/tools/llvm-mc/AsmLexer.cpp b/tools/llvm-mc/AsmLexer.cpp
index 27454ee922c..4dafa0eae94 100644
--- a/tools/llvm-mc/AsmLexer.cpp
+++ b/tools/llvm-mc/AsmLexer.cpp
@@ -101,17 +101,6 @@ AsmToken AsmLexer::LexIdentifier() {
   return AsmToken(AsmToken::Identifier, StringRef(TokStart, CurPtr - TokStart));
 }
 
-/// LexPercent: Register: %[a-zA-Z0-9]+
-AsmToken AsmLexer::LexPercent() {
-  if (!isalnum(*CurPtr))
-    return AsmToken(AsmToken::Percent, StringRef(CurPtr, 1));  // Single %.
-  
-  while (isalnum(*CurPtr))
-    ++CurPtr;
-  
-  return AsmToken(AsmToken::Register, StringRef(TokStart, CurPtr - TokStart));
-}
-
 /// LexSlash: Slash: /
 ///           C-Style Comment: /* ... */
 AsmToken AsmLexer::LexSlash() {
@@ -298,7 +287,7 @@ AsmToken AsmLexer::LexToken() {
     if (*CurPtr == '=')
       return ++CurPtr, AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
     return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
-  case '%': return LexPercent();
+  case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
   case '/': return LexSlash();
   case '#': return LexLineComment();
   case '"': return LexQuote();
diff --git a/tools/llvm-mc/AsmLexer.h b/tools/llvm-mc/AsmLexer.h
index 905ff75ec9f..000df59c88d 100644
--- a/tools/llvm-mc/AsmLexer.h
+++ b/tools/llvm-mc/AsmLexer.h
@@ -64,7 +64,6 @@ private:
   AsmToken ReturnError(const char *Loc, const std::string &Msg);
 
   AsmToken LexIdentifier();
-  AsmToken LexPercent();
   AsmToken LexSlash();
   AsmToken LexLineComment();
   AsmToken LexDigit();
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index fd0316460b6..84131c7ca66 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -120,9 +120,6 @@ static int AsLexInput(const char *ProgName) {
     case AsmToken::Identifier:
       outs() << "identifier: " << Lexer.getTok().getString() << '\n';
       break;
-    case AsmToken::Register:
-      outs() << "register: " << Lexer.getTok().getString() << '\n';
-      break;
     case AsmToken::String:
       outs() << "string: " << Lexer.getTok().getString() << '\n';
       break;