diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h
index 4ae21bf28cb7..e5ac72b6c449 100644
--- a/include/llvm/MC/MCAsmInfo.h
+++ b/include/llvm/MC/MCAsmInfo.h
@@ -363,6 +363,10 @@ class MCAsmInfo {
   // X86_64 ELF.
   bool RelaxELFRelocations = true;
 
+  // If true, then the lexer and expression parser will support %neg(),
+  // %hi(), and similar unary operators.
+  bool HasMipsExpressions = false;
+
 public:
   explicit MCAsmInfo();
   virtual ~MCAsmInfo();
@@ -582,6 +586,7 @@ class MCAsmInfo {
 
   bool canRelaxRelocations() const { return RelaxELFRelocations; }
   void setRelaxELFRelocations(bool V) { RelaxELFRelocations = V; }
+  bool hasMipsExpressions() const { return HasMipsExpressions; }
 };
 }
 
diff --git a/include/llvm/MC/MCParser/MCAsmLexer.h b/include/llvm/MC/MCParser/MCAsmLexer.h
index 3dd22c93d363..3097a0c9a293 100644
--- a/include/llvm/MC/MCParser/MCAsmLexer.h
+++ b/include/llvm/MC/MCParser/MCAsmLexer.h
@@ -55,7 +55,15 @@ class AsmToken {
     Pipe, PipePipe, Caret,
     Amp, AmpAmp, Exclaim, ExclaimEqual, Percent, Hash,
     Less, LessEqual, LessLess, LessGreater,
-    Greater, GreaterEqual, GreaterGreater, At
+    Greater, GreaterEqual, GreaterGreater, At,
+
+    // MIPS unary expression operators such as %neg.
+    PercentCall16, PercentCall_Hi, PercentCall_Lo, PercentDtprel_Hi,
+    PercentDtprel_Lo, PercentGot, PercentGot_Disp, PercentGot_Hi, PercentGot_Lo,
+    PercentGot_Ofst, PercentGot_Page, PercentGottprel, PercentGp_Rel, PercentHi,
+    PercentHigher, PercentHighest, PercentLo, PercentNeg, PercentPcrel_Hi,
+    PercentPcrel_Lo, PercentTlsgd, PercentTlsldm, PercentTprel_Hi,
+    PercentTprel_Lo
   };
 
 private:
diff --git a/include/llvm/MC/MCParser/MCTargetAsmParser.h b/include/llvm/MC/MCParser/MCTargetAsmParser.h
index 08a84a8b9c9e..b2f7b8ee5a87 100644
--- a/include/llvm/MC/MCParser/MCTargetAsmParser.h
+++ b/include/llvm/MC/MCParser/MCTargetAsmParser.h
@@ -228,6 +228,12 @@ class MCTargetAsmParser : public MCAsmParserExtension {
   /// Ensure that all previously parsed instructions have been emitted to the
   /// output streamer, if the target does not emit them immediately.
   virtual void flushPendingInstructions(MCStreamer &Out) { }
+
+  virtual const MCExpr *createTargetUnaryExpr(const MCExpr *E,
+                                              AsmToken::TokenKind OperatorToken,
+                                              MCContext &Ctx) {
+    return nullptr;
+  }
 };
 
 } // End llvm namespace
diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
index 7037bb1d5fab..be6e84460ea4 100644
--- a/lib/MC/MCParser/AsmLexer.cpp
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/MC/MCParser/AsmLexer.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -600,7 +601,46 @@ AsmToken AsmLexer::LexToken() {
       return AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
     }
     return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
-  case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
+  case '%':
+    if (MAI.hasMipsExpressions()) {
+      AsmToken::TokenKind Operator;
+      unsigned OperatorLength;
+
+      std::tie(Operator, OperatorLength) =
+          StringSwitch<std::pair<AsmToken::TokenKind, unsigned>>(
+              StringRef(CurPtr))
+              .StartsWith("call16", {AsmToken::PercentCall16, 7})
+              .StartsWith("call_hi", {AsmToken::PercentCall_Hi, 8})
+              .StartsWith("call_lo", {AsmToken::PercentCall_Lo, 8})
+              .StartsWith("dtprel_hi", {AsmToken::PercentDtprel_Hi, 10})
+              .StartsWith("dtprel_lo", {AsmToken::PercentDtprel_Lo, 10})
+              .StartsWith("got_disp", {AsmToken::PercentGot_Disp, 9})
+              .StartsWith("got_hi", {AsmToken::PercentGot_Hi, 7})
+              .StartsWith("got_lo", {AsmToken::PercentGot_Lo, 7})
+              .StartsWith("got_ofst", {AsmToken::PercentGot_Ofst, 9})
+              .StartsWith("got_page", {AsmToken::PercentGot_Page, 9})
+              .StartsWith("gottprel", {AsmToken::PercentGottprel, 9})
+              .StartsWith("got", {AsmToken::PercentGot, 4})
+              .StartsWith("gp_rel", {AsmToken::PercentGp_Rel, 7})
+              .StartsWith("higher", {AsmToken::PercentHigher, 7})
+              .StartsWith("highest", {AsmToken::PercentHighest, 8})
+              .StartsWith("hi", {AsmToken::PercentHi, 3})
+              .StartsWith("lo", {AsmToken::PercentLo, 3})
+              .StartsWith("neg", {AsmToken::PercentNeg, 4})
+              .StartsWith("pcrel_hi", {AsmToken::PercentPcrel_Hi, 9})
+              .StartsWith("pcrel_lo", {AsmToken::PercentPcrel_Lo, 9})
+              .StartsWith("tlsgd", {AsmToken::PercentTlsgd, 6})
+              .StartsWith("tlsldm", {AsmToken::PercentTlsldm, 7})
+              .StartsWith("tprel_hi", {AsmToken::PercentTprel_Hi, 9})
+              .StartsWith("tprel_lo", {AsmToken::PercentTprel_Lo, 9})
+              .Default({AsmToken::Percent, 1});
+
+      if (Operator != AsmToken::Percent) {
+        CurPtr += OperatorLength - 1;
+        return AsmToken(Operator, StringRef(TokStart, OperatorLength));
+      }
+    }
+    return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
   case '/':
     IsAtStartOfStatement = OldIsAtStartOfStatement;
     return LexSlash();
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 6d3240a3e11a..7a6d5dbd2d32 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -1064,6 +1064,43 @@ bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
       return true;
     Res = MCUnaryExpr::createNot(Res, getContext());
     return false;
+  // MIPS unary expression operators. The lexer won't generate these tokens if
+  // MCAsmInfo::HasMipsExpressions is false for the target.
+  case AsmToken::PercentCall16:
+  case AsmToken::PercentCall_Hi:
+  case AsmToken::PercentCall_Lo:
+  case AsmToken::PercentDtprel_Hi:
+  case AsmToken::PercentDtprel_Lo:
+  case AsmToken::PercentGot:
+  case AsmToken::PercentGot_Disp:
+  case AsmToken::PercentGot_Hi:
+  case AsmToken::PercentGot_Lo:
+  case AsmToken::PercentGot_Ofst:
+  case AsmToken::PercentGot_Page:
+  case AsmToken::PercentGottprel:
+  case AsmToken::PercentGp_Rel:
+  case AsmToken::PercentHi:
+  case AsmToken::PercentHigher:
+  case AsmToken::PercentHighest:
+  case AsmToken::PercentLo:
+  case AsmToken::PercentNeg:
+  case AsmToken::PercentPcrel_Hi:
+  case AsmToken::PercentPcrel_Lo:
+  case AsmToken::PercentTlsgd:
+  case AsmToken::PercentTlsldm:
+  case AsmToken::PercentTprel_Hi:
+  case AsmToken::PercentTprel_Lo:
+    Lex(); // Eat the operator.
+    if (Lexer.isNot(AsmToken::LParen))
+      return TokError("expected '(' after operator");
+    Lex(); // Eat the operator.
+    if (parseExpression(Res, EndLoc))
+      return true;
+    if (Lexer.isNot(AsmToken::RParen))
+      return TokError("expected ')'");
+    Lex(); // Eat the operator.
+    Res = getTargetParser().createTargetUnaryExpr(Res, FirstTokenKind, Ctx);
+    return !Res;
   }
 }
 
diff --git a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index 0291ef929e2c..e3f0d16d6609 100644
--- a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -252,9 +252,6 @@ class MipsAsmParser : public MCTargetAsmParser {
   bool reportParseError(SMLoc Loc, Twine ErrorMsg);
 
   bool parseMemOffset(const MCExpr *&Res, bool isParenExpr);
-  bool parseRelocOperand(const MCExpr *&Res);
-
-  const MCExpr *evaluateRelocExpr(const MCExpr *Expr, StringRef RelocStr);
 
   bool isEvaluated(const MCExpr *Expr);
   bool parseSetMips0Directive();
@@ -552,6 +549,64 @@ class MipsAsmParser : public MCTargetAsmParser {
   void warnIfNoMacro(SMLoc Loc);
 
   bool isLittle() const { return IsLittleEndian; }
+
+  const MCExpr *createTargetUnaryExpr(const MCExpr *E,
+                                      AsmToken::TokenKind OperatorToken,
+                                      MCContext &Ctx) override {
+    switch(OperatorToken) {
+    default:
+      llvm_unreachable("Unknown token");
+      return nullptr;
+    case AsmToken::PercentCall16:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_CALL, E, Ctx);
+    case AsmToken::PercentCall_Hi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_CALL_HI16, E, Ctx);
+    case AsmToken::PercentCall_Lo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_CALL_LO16, E, Ctx);
+    case AsmToken::PercentDtprel_Hi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_DTPREL_HI, E, Ctx);
+    case AsmToken::PercentDtprel_Lo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_DTPREL_LO, E, Ctx);
+    case AsmToken::PercentGot:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT, E, Ctx);
+    case AsmToken::PercentGot_Disp:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_DISP, E, Ctx);
+    case AsmToken::PercentGot_Hi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_HI16, E, Ctx);
+    case AsmToken::PercentGot_Lo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_LO16, E, Ctx);
+    case AsmToken::PercentGot_Ofst:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_OFST, E, Ctx);
+    case AsmToken::PercentGot_Page:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOT_PAGE, E, Ctx);
+    case AsmToken::PercentGottprel:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GOTTPREL, E, Ctx);
+    case AsmToken::PercentGp_Rel:
+      return MipsMCExpr::create(MipsMCExpr::MEK_GPREL, E, Ctx);
+    case AsmToken::PercentHi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_HI, E, Ctx);
+    case AsmToken::PercentHigher:
+      return MipsMCExpr::create(MipsMCExpr::MEK_HIGHER, E, Ctx);
+    case AsmToken::PercentHighest:
+      return MipsMCExpr::create(MipsMCExpr::MEK_HIGHEST, E, Ctx);
+    case AsmToken::PercentLo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_LO, E, Ctx);
+    case AsmToken::PercentNeg:
+      return MipsMCExpr::create(MipsMCExpr::MEK_NEG, E, Ctx);
+    case AsmToken::PercentPcrel_Hi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_PCREL_HI16, E, Ctx);
+    case AsmToken::PercentPcrel_Lo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_PCREL_LO16, E, Ctx);
+    case AsmToken::PercentTlsgd:
+      return MipsMCExpr::create(MipsMCExpr::MEK_TLSGD, E, Ctx);
+    case AsmToken::PercentTlsldm:
+      return MipsMCExpr::create(MipsMCExpr::MEK_TLSLDM, E, Ctx);
+    case AsmToken::PercentTprel_Hi:
+      return MipsMCExpr::create(MipsMCExpr::MEK_TPREL_HI, E, Ctx);
+    case AsmToken::PercentTprel_Lo:
+      return MipsMCExpr::create(MipsMCExpr::MEK_TPREL_LO, E, Ctx);
+    }
+  }
 };
 }
 
@@ -4187,9 +4242,6 @@ bool MipsAsmParser::parseOperand(OperandVector &Operands, StringRef Mnemonic) {
   DEBUG(dbgs() << ".. Generic Parser\n");
 
   switch (getLexer().getKind()) {
-  default:
-    Error(Parser.getTok().getLoc(), "unexpected token in operand");
-    return true;
   case AsmToken::Dollar: {
     // Parse the register.
     SMLoc S = Parser.getTok().getLoc();
@@ -4216,72 +4268,23 @@ bool MipsAsmParser::parseOperand(OperandVector &Operands, StringRef Mnemonic) {
     Operands.push_back(MipsOperand::CreateImm(Res, S, E, *this));
     return false;
   }
-  // Else drop to expression parsing.
-  case AsmToken::LParen:
-  case AsmToken::Minus:
-  case AsmToken::Plus:
-  case AsmToken::Integer:
-  case AsmToken::Tilde:
-  case AsmToken::String: {
-    DEBUG(dbgs() << ".. generic integer\n");
-    OperandMatchResultTy ResTy = parseImm(Operands);
-    return ResTy != MatchOperand_Success;
-  }
-  case AsmToken::Percent: {
-    // It is a symbol reference or constant expression.
-    const MCExpr *IdVal;
+  default: {
+    DEBUG(dbgs() << ".. generic integer expression\n");
+
+    const MCExpr *Expr;
     SMLoc S = Parser.getTok().getLoc(); // Start location of the operand.
-    if (parseRelocOperand(IdVal))
+    if (getParser().parseExpression(Expr))
       return true;
 
     SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
 
-    Operands.push_back(MipsOperand::CreateImm(IdVal, S, E, *this));
+    Operands.push_back(MipsOperand::CreateImm(Expr, S, E, *this));
     return false;
-  } // case AsmToken::Percent
+  }
   } // switch(getLexer().getKind())
   return true;
 }
 
-const MCExpr *MipsAsmParser::evaluateRelocExpr(const MCExpr *Expr,
-                                               StringRef RelocStr) {
-  if (RelocStr == "hi(%neg(%gp_rel")
-    return MipsMCExpr::createGpOff(MipsMCExpr::MEK_HI, Expr, getContext());
-  else if (RelocStr == "lo(%neg(%gp_rel")
-    return MipsMCExpr::createGpOff(MipsMCExpr::MEK_LO, Expr, getContext());
-
-  MipsMCExpr::MipsExprKind Kind =
-      StringSwitch<MipsMCExpr::MipsExprKind>(RelocStr)
-          .Case("call16", MipsMCExpr::MEK_GOT_CALL)
-          .Case("call_hi", MipsMCExpr::MEK_CALL_HI16)
-          .Case("call_lo", MipsMCExpr::MEK_CALL_LO16)
-          .Case("dtprel_hi", MipsMCExpr::MEK_DTPREL_HI)
-          .Case("dtprel_lo", MipsMCExpr::MEK_DTPREL_LO)
-          .Case("got", MipsMCExpr::MEK_GOT)
-          .Case("got_disp", MipsMCExpr::MEK_GOT_DISP)
-          .Case("got_hi", MipsMCExpr::MEK_GOT_HI16)
-          .Case("got_lo", MipsMCExpr::MEK_GOT_LO16)
-          .Case("got_ofst", MipsMCExpr::MEK_GOT_OFST)
-          .Case("got_page", MipsMCExpr::MEK_GOT_PAGE)
-          .Case("gottprel", MipsMCExpr::MEK_GOTTPREL)
-          .Case("gp_rel", MipsMCExpr::MEK_GPREL)
-          .Case("hi", MipsMCExpr::MEK_HI)
-          .Case("higher", MipsMCExpr::MEK_HIGHER)
-          .Case("highest", MipsMCExpr::MEK_HIGHEST)
-          .Case("lo", MipsMCExpr::MEK_LO)
-          .Case("neg", MipsMCExpr::MEK_NEG)
-          .Case("pcrel_hi", MipsMCExpr::MEK_PCREL_HI16)
-          .Case("pcrel_lo", MipsMCExpr::MEK_PCREL_LO16)
-          .Case("tlsgd", MipsMCExpr::MEK_TLSGD)
-          .Case("tlsldm", MipsMCExpr::MEK_TLSLDM)
-          .Case("tprel_hi", MipsMCExpr::MEK_TPREL_HI)
-          .Case("tprel_lo", MipsMCExpr::MEK_TPREL_LO)
-          .Default(MipsMCExpr::MEK_None);
-
-  assert(Kind != MipsMCExpr::MEK_None);
-  return MipsMCExpr::create(Kind, Expr, getContext());
-}
-
 bool MipsAsmParser::isEvaluated(const MCExpr *Expr) {
 
   switch (Expr->getKind()) {
@@ -4303,49 +4306,6 @@ bool MipsAsmParser::isEvaluated(const MCExpr *Expr) {
   return false;
 }
 
-bool MipsAsmParser::parseRelocOperand(const MCExpr *&Res) {
-  MCAsmParser &Parser = getParser();
-  Parser.Lex();                          // Eat the % token.
-  const AsmToken &Tok = Parser.getTok(); // Get next token, operation.
-  if (Tok.isNot(AsmToken::Identifier))
-    return true;
-
-  std::string Str = Tok.getIdentifier();
-
-  Parser.Lex(); // Eat the identifier.
-  // Now make an expression from the rest of the operand.
-  const MCExpr *IdVal;
-  SMLoc EndLoc;
-
-  if (getLexer().getKind() == AsmToken::LParen) {
-    while (1) {
-      Parser.Lex(); // Eat the '(' token.
-      if (getLexer().getKind() == AsmToken::Percent) {
-        Parser.Lex(); // Eat the % token.
-        const AsmToken &nextTok = Parser.getTok();
-        if (nextTok.isNot(AsmToken::Identifier))
-          return true;
-        Str += "(%";
-        Str += nextTok.getIdentifier();
-        Parser.Lex(); // Eat the identifier.
-        if (getLexer().getKind() != AsmToken::LParen)
-          return true;
-      } else
-        break;
-    }
-    if (getParser().parseParenExpression(IdVal, EndLoc))
-      return true;
-
-    while (getLexer().getKind() == AsmToken::RParen)
-      Parser.Lex(); // Eat the ')' token.
-
-  } else
-    return true; // Parenthesis must follow the relocation operand.
-
-  Res = evaluateRelocExpr(IdVal, Str);
-  return false;
-}
-
 bool MipsAsmParser::ParseRegister(unsigned &RegNo, SMLoc &StartLoc,
                                   SMLoc &EndLoc) {
   SmallVector<std::unique_ptr<MCParsedAsmOperand>, 1> Operands;
@@ -4373,35 +4333,11 @@ bool MipsAsmParser::ParseRegister(unsigned &RegNo, SMLoc &StartLoc,
 }
 
 bool MipsAsmParser::parseMemOffset(const MCExpr *&Res, bool isParenExpr) {
-  MCAsmParser &Parser = getParser();
   SMLoc S;
-  bool Result = true;
-  unsigned NumOfLParen = 0;
-
-  while (getLexer().getKind() == AsmToken::LParen) {
-    Parser.Lex();
-    ++NumOfLParen;
-  }
 
-  switch (getLexer().getKind()) {
-  default:
-    return true;
-  case AsmToken::Identifier:
-  case AsmToken::LParen:
-  case AsmToken::Integer:
-  case AsmToken::Minus:
-  case AsmToken::Plus:
-    if (isParenExpr)
-      Result = getParser().parseParenExprOfDepth(NumOfLParen, Res, S);
-    else
-      Result = (getParser().parseExpression(Res));
-    while (getLexer().getKind() == AsmToken::RParen)
-      Parser.Lex();
-    break;
-  case AsmToken::Percent:
-    Result = parseRelocOperand(Res);
-  }
-  return Result;
+  if (isParenExpr)
+    return getParser().parseParenExprOfDepth(0, Res, S);
+  return getParser().parseExpression(Res);
 }
 
 MipsAsmParser::OperandMatchResultTy
@@ -4631,31 +4567,6 @@ MipsAsmParser::parseAnyRegister(OperandVector &Operands) {
   return ResTy;
 }
 
-MipsAsmParser::OperandMatchResultTy
-MipsAsmParser::parseImm(OperandVector &Operands) {
-  MCAsmParser &Parser = getParser();
-  switch (getLexer().getKind()) {
-  default:
-    return MatchOperand_NoMatch;
-  case AsmToken::LParen:
-  case AsmToken::Minus:
-  case AsmToken::Plus:
-  case AsmToken::Integer:
-  case AsmToken::Tilde:
-  case AsmToken::String:
-    break;
-  }
-
-  const MCExpr *IdVal;
-  SMLoc S = Parser.getTok().getLoc();
-  if (getParser().parseExpression(IdVal))
-    return MatchOperand_ParseFail;
-
-  SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
-  Operands.push_back(MipsOperand::CreateImm(IdVal, S, E, *this));
-  return MatchOperand_Success;
-}
-
 MipsAsmParser::OperandMatchResultTy
 MipsAsmParser::parseJumpTarget(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
@@ -4663,16 +4574,12 @@ MipsAsmParser::parseJumpTarget(OperandVector &Operands) {
 
   SMLoc S = getLexer().getLoc();
 
-  // Integers and expressions are acceptable
-  OperandMatchResultTy ResTy = parseImm(Operands);
-  if (ResTy != MatchOperand_NoMatch)
-    return ResTy;
-
   // Registers are a valid target and have priority over symbols.
-  ResTy = parseAnyRegister(Operands);
+  OperandMatchResultTy ResTy = parseAnyRegister(Operands);
   if (ResTy != MatchOperand_NoMatch)
     return ResTy;
 
+  // Integers and expressions are acceptable
   const MCExpr *Expr = nullptr;
   if (Parser.parseExpression(Expr)) {
     // We have no way of knowing if a symbol was consumed so we must ParseFail
diff --git a/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
index 550c2894695c..3ee0cd9c7ec6 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -62,6 +62,8 @@ static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
   case FK_GPRel_4:
   case FK_Data_4:
   case FK_Data_8:
+  case Mips::fixup_Mips_SUB:
+  case Mips::fixup_MICROMIPS_SUB:
     break;
   case Mips::fixup_Mips_PC16:
     // The displacement is then divided by 4 to give us an 18 bit
@@ -361,7 +363,9 @@ getFixupKindInfo(MCFixupKind Kind) const {
     { "fixup_MICROMIPS_TLS_DTPREL_HI16", 0,     16,   0 },
     { "fixup_MICROMIPS_TLS_DTPREL_LO16", 0,     16,   0 },
     { "fixup_MICROMIPS_TLS_TPREL_HI16",  0,     16,   0 },
-    { "fixup_MICROMIPS_TLS_TPREL_LO16",  0,     16,   0 }
+    { "fixup_MICROMIPS_TLS_TPREL_LO16",  0,     16,   0 },
+    { "fixup_Mips_SUB",                  0,     64,   0 },
+    { "fixup_MICROMIPS_SUB",             0,     64,   0 }
   };
 
   const static MCFixupKindInfo BigEndianInfos[Mips::NumTargetFixupKinds] = {
@@ -430,7 +434,9 @@ getFixupKindInfo(MCFixupKind Kind) const {
     { "fixup_MICROMIPS_TLS_DTPREL_HI16", 16,     16,   0 },
     { "fixup_MICROMIPS_TLS_DTPREL_LO16", 16,     16,   0 },
     { "fixup_MICROMIPS_TLS_TPREL_HI16",  16,     16,   0 },
-    { "fixup_MICROMIPS_TLS_TPREL_LO16",  16,     16,   0 }
+    { "fixup_MICROMIPS_TLS_TPREL_LO16",  16,     16,   0 },
+    { "fixup_Mips_SUB",                   0,     64,   0 },
+    { "fixup_MICROMIPS_SUB",              0,     64,   0 }
   };
 
   if (Kind < FirstTargetFixupKind)
diff --git a/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp b/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
index 20c5f3691d23..99ba18c972df 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
@@ -329,6 +329,8 @@ unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
     return ELF::R_MIPS_HIGHER;
   case Mips::fixup_Mips_HIGHEST:
     return ELF::R_MIPS_HIGHEST;
+  case Mips::fixup_Mips_SUB:
+    return ELF::R_MIPS_SUB;
   case Mips::fixup_Mips_GOT_HI16:
     return ELF::R_MIPS_GOT_HI16;
   case Mips::fixup_Mips_GOT_LO16:
@@ -365,6 +367,8 @@ unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
     return ELF::R_MICROMIPS_TLS_TPREL_HI16;
   case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
     return ELF::R_MICROMIPS_TLS_TPREL_LO16;
+  case Mips::fixup_MICROMIPS_SUB:
+    return ELF::R_MICROMIPS_SUB;
   }
 
   llvm_unreachable("invalid fixup kind!");
diff --git a/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h b/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
index b4d8e9494650..149296212eca 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
+++ b/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
@@ -209,6 +209,10 @@ namespace Mips {
     // resulting in - R_MICROMIPS_TLS_TPREL_LO16
     fixup_MICROMIPS_TLS_TPREL_LO16,
 
+    // resulting in - R_MIPS_SUB/R_MICROMIPS_SUB
+    fixup_Mips_SUB,
+    fixup_MICROMIPS_SUB,
+
     // Marker
     LastTargetFixupKind,
     NumTargetFixupKinds = LastTargetFixupKind - FirstTargetFixupKind
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
index 1ce8f07092b1..2c01f919befc 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
@@ -49,6 +49,7 @@ MipsMCAsmInfo::MipsMCAsmInfo(const Triple &TheTriple) {
   SupportsDebugInformation = true;
   ExceptionsType = ExceptionHandling::DwarfCFI;
   DwarfRegNumForCFI = true;
+  HasMipsExpressions = true;
 
   // Enable IAS by default for O32.
   if (TheTriple.getArch() == Triple::mips ||
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
index c15c8a929bf1..4cc55f86a993 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -637,7 +637,6 @@ getExprOpValue(const MCExpr *Expr, SmallVectorImpl<MCFixup> &Fixups,
 
     Mips::Fixups FixupKind = Mips::Fixups(0);
     switch (MipsExpr->getKind()) {
-    case MipsMCExpr::MEK_NEG:
     case MipsMCExpr::MEK_None:
     case MipsMCExpr::MEK_Special:
       llvm_unreachable("Unhandled fixup kind!");
@@ -735,6 +734,10 @@ getExprOpValue(const MCExpr *Expr, SmallVectorImpl<MCFixup> &Fixups,
       FixupKind = isMicroMips(STI) ? Mips::fixup_MICROMIPS_TLS_TPREL_LO16
                                    : Mips::fixup_Mips_TPREL_LO;
       break;
+    case MipsMCExpr::MEK_NEG:
+      FixupKind =
+          isMicroMips(STI) ? Mips::fixup_MICROMIPS_SUB : Mips::fixup_Mips_SUB;
+      break;
     }
     Fixups.push_back(MCFixup::create(0, MipsExpr, MCFixupKind(FixupKind)));
     return 0;
diff --git a/test/MC/Mips/expr1.s b/test/MC/Mips/expr1.s
index a6ecff5d212c..a1897126abeb 100644
--- a/test/MC/Mips/expr1.s
+++ b/test/MC/Mips/expr1.s
@@ -10,17 +10,20 @@
 # 32R2-EL: lw   $4, %lo(foo)($4)       # encoding: [A,A,0x84,0x8c]
 # 32R2-EL:                             #   fixup A - offset: 0, value: %lo(foo), kind: fixup_Mips_LO16
 # 32R2-EL: lw   $4, 56($4)             # encoding: [0x38,0x00,0x84,0x8c]
-# 32R2-EL: lw   $4, %lo(8+foo)($4)     # encoding: [A,A,0x84,0x8c]
-# 32R2-EL:                             #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_Mips_LO16
-# 32R2-EL: lw   $4, %lo(8+foo)($4)     # encoding: [A,A,0x84,0x8c]
-# 32R2-EL:                             #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_Mips_LO16
-# 32R2-EL: lw   $4, %lo(8+foo)($4)     # encoding: [A,A,0x84,0x8c]
-# 32R2-EL:                             #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_Mips_LO16
+# 32R2-EL: lui  $1, %hi(foo+(%lo(8)))     # encoding: [A,A,0x01,0x3c]
+# 32R2-EL:                                #   fixup A - offset: 0, value: %hi(foo+(%lo(8))), kind: fixup_Mips_HI16
+# 32R2-EL: addu $1, $1, $4                # encoding: [0x21,0x08,0x24,0x00]
+# 32R2-EL: lw   $4, %lo(foo+(%lo(8)))($1) # encoding: [A,A,0x24,0x8c]
+# 32R2-EL:                                #   fixup A - offset: 0, value: %lo(foo+(%lo(8))), kind: fixup_Mips_LO16
+# 32R2-EL: lw   $4, %lo(12+foo)($4)    # encoding: [A,A,0x84,0x8c]
+# 32R2-EL:                             #   fixup A - offset: 0, value: %lo(12+foo), kind: fixup_Mips_LO16
+# 32R2-EL: lw   $4, %lo(16+foo)($4)    # encoding: [A,A,0x84,0x8c]
+# 32R2-EL:                             #   fixup A - offset: 0, value: %lo(16+foo), kind: fixup_Mips_LO16
 # 32R2-EL: lw   $4, 10($4)             # encoding: [0x0a,0x00,0x84,0x8c]
 # 32R2-EL: lw   $4, 15($4)             # encoding: [0x0f,0x00,0x84,0x8c]
 # 32R2-EL: lw   $4, 21($4)             # encoding: [0x15,0x00,0x84,0x8c]
 # 32R2-EL: lw   $4, 28($4)             # encoding: [0x1c,0x00,0x84,0x8c]
-# 32R2-EL: lw   $4, %lo(65542)($4)     # encoding: [0x06,0x00,0x84,0x8c]
+# 32R2-EL: lw   $4, 6($4)              # encoding: [0x06,0x00,0x84,0x8c]
 # 32R2-EL: .space  64
 
 # MM-32R2-EL: .text
@@ -29,17 +32,20 @@
 # MM-32R2-EL: lw   $4, %lo(foo)($4)     # encoding: [0x84'A',0xfc'A',0x00,0x00]
 # MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(foo), kind: fixup_MICROMIPS_LO16
 # MM-32R2-EL: lw   $4, 56($4)           # encoding: [0x84,0xfc,0x38,0x00]
-# MM-32R2-EL: lw   $4, %lo(8+foo)($4)   # encoding: [0x84'A',0xfc'A',0x00,0x00]
-# MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_MICROMIPS_LO16
-# MM-32R2-EL: lw   $4, %lo(8+foo)($4)   # encoding: [0x84'A',0xfc'A',0x00,0x00]
-# MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_MICROMIPS_LO16
-# MM-32R2-EL: lw   $4, %lo(8+foo)($4)   # encoding: [0x84'A',0xfc'A',0x00,0x00]
-# MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(8+foo), kind: fixup_MICROMIPS_LO16
+# MM-32R2-EL: lui $1, %hi(foo+(%lo(8)))    # encoding: [0xa1'A',0x41'A',0x00,0x00]
+# MM-32R2-EL:                              #   fixup A - offset: 0, value: %hi(foo+(%lo(8))), kind: fixup_MICROMIPS_HI16
+# MM-32R2-EL: addu $1, $1, $4              # encoding: [0x81,0x00,0x50,0x09]
+# MM-32R2-EL: lw $4, %lo(foo+(%lo(8)))($1) # encoding: [0x81'A',0xfc'A',0x00,0x00]
+# MM-32R2-EL:                              #   fixup A - offset: 0, value: %lo(foo+(%lo(8))), kind: fixup_MICROMIPS_LO16
+# MM-32R2-EL: lw   $4, %lo(12+foo)($4)  # encoding: [0x84'A',0xfc'A',0x00,0x00]
+# MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(12+foo), kind: fixup_MICROMIPS_LO16
+# MM-32R2-EL: lw   $4, %lo(16+foo)($4)  # encoding: [0x84'A',0xfc'A',0x00,0x00]
+# MM-32R2-EL:                           #   fixup A - offset: 0, value: %lo(16+foo), kind: fixup_MICROMIPS_LO16
 # MM-32R2-EL: lw   $4, 10($4)           # encoding: [0x84,0xfc,0x0a,0x00]
 # MM-32R2-EL: lw   $4, 15($4)           # encoding: [0x84,0xfc,0x0f,0x00]
 # MM-32R2-EL: lw   $4, 21($4)           # encoding: [0x84,0xfc,0x15,0x00]
 # MM-32R2-EL: lw   $4, 28($4)           # encoding: [0x84,0xfc,0x1c,0x00]
-# MM-32R2-EL: lw   $4, %lo(65542)($4)   # encoding: [0x84,0xfc,0x06,0x00]
+# MM-32R2-EL: lw   $4, 6($4)            # encoding: [0x84,0xfc,0x06,0x00]
 # MM-32R2-EL: .space  64
 
   .globl  foo
@@ -48,8 +54,8 @@ foo:
   lw  $4,%lo(foo)($4)
   lw  $4,((10 + 4) * 4)($4)
   lw  $4,%lo (2 * 4) + foo($4)
-  lw  $4,%lo((2 * 4) + foo)($4)
-  lw  $4,(((%lo ((2 * 4) + foo))))($4)
+  lw  $4,%lo((3 * 4) + foo)($4)
+  lw  $4,(((%lo ((4 * 4) + foo))))($4)
   lw  $4, (((1+2)+3)+4)($4)
   lw  $4, ((((1+2)+3)+4)+5)($4)
   lw  $4, (((((1+2)+3)+4)+5)+6)($4)
diff --git a/test/MC/Mips/relocation.s b/test/MC/Mips/relocation.s
index 42a015dbdb95..a73d9530f1c5 100644
--- a/test/MC/Mips/relocation.s
+++ b/test/MC/Mips/relocation.s
@@ -153,7 +153,10 @@ baz:    .long foo                          // RELOC: R_MIPS_32 foo
                                            // ENCLE: addiu $2, $3, %got_lo(foo) # encoding: [A,A,0x62,0x24]
                                            // FIXUP: # fixup A - offset: 0, value: %got_lo(foo), kind: fixup_Mips_GOT_LO16
 
-//      addiu $2, $3, %neg(foo)            // FIXME: R_MIPS_SUB foo
+        // It turns out that %neg() isn't actually usable for anything. It's
+        // not supported in .quad and it doesn't make sense to use a 64-bit
+        // reloc on a 32-bit instruction.
+        // .quad %neg(foo)                 // ?????: R_MIPS_SUB foo
                                            // ?????: R_MIPS_INSERT_A
                                            // ?????: R_MIPS_INSERT_B
                                            // ?????: R_MIPS_DELETE
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index 01853a5c84ee..81ee3d83d559 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -314,6 +314,78 @@ static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
     case AsmToken::Slash:          OS << "Slash"; break;
     case AsmToken::Star:           OS << "Star"; break;
     case AsmToken::Tilde:          OS << "Tilde"; break;
+    case AsmToken::PercentCall16:
+      OS << "PercentCall16";
+      break;
+    case AsmToken::PercentCall_Hi:
+      OS << "PercentCall_Hi";
+      break;
+    case AsmToken::PercentCall_Lo:
+      OS << "PercentCall_Lo";
+      break;
+    case AsmToken::PercentDtprel_Hi:
+      OS << "PercentDtprel_Hi";
+      break;
+    case AsmToken::PercentDtprel_Lo:
+      OS << "PercentDtprel_Lo";
+      break;
+    case AsmToken::PercentGot:
+      OS << "PercentGot";
+      break;
+    case AsmToken::PercentGot_Disp:
+      OS << "PercentGot_Disp";
+      break;
+    case AsmToken::PercentGot_Hi:
+      OS << "PercentGot_Hi";
+      break;
+    case AsmToken::PercentGot_Lo:
+      OS << "PercentGot_Lo";
+      break;
+    case AsmToken::PercentGot_Ofst:
+      OS << "PercentGot_Ofst";
+      break;
+    case AsmToken::PercentGot_Page:
+      OS << "PercentGot_Page";
+      break;
+    case AsmToken::PercentGottprel:
+      OS << "PercentGottprel";
+      break;
+    case AsmToken::PercentGp_Rel:
+      OS << "PercentGp_Rel";
+      break;
+    case AsmToken::PercentHi:
+      OS << "PercentHi";
+      break;
+    case AsmToken::PercentHigher:
+      OS << "PercentHigher";
+      break;
+    case AsmToken::PercentHighest:
+      OS << "PercentHighest";
+      break;
+    case AsmToken::PercentLo:
+      OS << "PercentLo";
+      break;
+    case AsmToken::PercentNeg:
+      OS << "PercentNeg";
+      break;
+    case AsmToken::PercentPcrel_Hi:
+      OS << "PercentPcrel_Hi";
+      break;
+    case AsmToken::PercentPcrel_Lo:
+      OS << "PercentPcrel_Lo";
+      break;
+    case AsmToken::PercentTlsgd:
+      OS << "PercentTlsgd";
+      break;
+    case AsmToken::PercentTlsldm:
+      OS << "PercentTlsldm";
+      break;
+    case AsmToken::PercentTprel_Hi:
+      OS << "PercentTprel_Hi";
+      break;
+    case AsmToken::PercentTprel_Lo:
+      OS << "PercentTprel_Lo";
+      break;
     }
 
     // Print the token string.