Index: llvm/trunk/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
===================================================================
--- llvm/trunk/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
+++ llvm/trunk/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
@@ -78,6 +78,8 @@
   // Custom parse functions for Sparc specific operands.
   OperandMatchResultTy parseMEMOperand(OperandVector &Operands);
 
+  OperandMatchResultTy parseMembarTag(OperandVector &Operands);
+
   OperandMatchResultTy parseOperand(OperandVector &Operands, StringRef Name);
 
   OperandMatchResultTy
@@ -256,6 +258,7 @@
   bool isMem() const override { return isMEMrr() || isMEMri(); }
   bool isMEMrr() const { return Kind == k_MemoryReg; }
   bool isMEMri() const { return Kind == k_MemoryImm; }
+  bool isMembarTag() const { return Kind == k_Immediate; }
 
   bool isIntReg() const {
     return (Kind == k_Register && Reg.Kind == rk_IntReg);
@@ -366,6 +369,12 @@
     addExpr(Inst, Expr);
   }
 
+  void addMembarTagOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 1 && "Invalid number of operands!");
+    const MCExpr *Expr = getImm();
+    addExpr(Inst, Expr);
+  }
+
   static std::unique_ptr<SparcOperand> CreateToken(StringRef Str, SMLoc S) {
     auto Op = make_unique<SparcOperand>(k_Token);
     Op->Tok.Data = Str.data();
@@ -742,6 +751,52 @@
   return MatchOperand_Success;
 }
 
+OperandMatchResultTy SparcAsmParser::parseMembarTag(OperandVector &Operands) {
+  SMLoc S = Parser.getTok().getLoc();
+  const MCExpr *EVal;
+  int64_t ImmVal = 0;
+
+  std::unique_ptr<SparcOperand> Mask;
+  if (parseSparcAsmOperand(Mask) == MatchOperand_Success) {
+    if (!Mask->isImm() || !Mask->getImm()->evaluateAsAbsolute(ImmVal) ||
+        ImmVal < 0 || ImmVal > 127) {
+      Error(S, "invalid membar mask number");
+      return MatchOperand_ParseFail;
+    }
+  }
+
+  while (getLexer().getKind() == AsmToken::Hash) {
+    SMLoc TagStart = getLexer().getLoc();
+    Parser.Lex(); // Eat the '#'.
+    unsigned MaskVal = StringSwitch<unsigned>(Parser.getTok().getString())
+      .Case("LoadLoad", 0x1)
+      .Case("StoreLoad", 0x2)
+      .Case("LoadStore", 0x4)
+      .Case("StoreStore", 0x8)
+      .Case("Lookaside", 0x10)
+      .Case("MemIssue", 0x20)
+      .Case("Sync", 0x40)
+      .Default(0);
+
+    Parser.Lex(); // Eat the identifier token.
+
+    if (!MaskVal) {
+      Error(TagStart, "unknown membar tag");
+      return MatchOperand_ParseFail;
+    }
+
+    ImmVal |= MaskVal;
+
+    if (getLexer().getKind() == AsmToken::Pipe)
+      Parser.Lex(); // Eat the '|'.
+  }
+
+  EVal = MCConstantExpr::create(ImmVal, getContext());
+  SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
+  Operands.push_back(SparcOperand::CreateImm(EVal, S, E));
+  return MatchOperand_Success;
+}
+
 OperandMatchResultTy
 SparcAsmParser::parseOperand(OperandVector &Operands, StringRef Mnemonic) {
 
Index: llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.h
===================================================================
--- llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.h
+++ llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.h
@@ -49,6 +49,8 @@
                       raw_ostream &OS);
   bool printGetPCX(const MCInst *MI, unsigned OpNo, const MCSubtargetInfo &STI,
                    raw_ostream &OS);
+  void printMembarTag(const MCInst *MI, int opNum, const MCSubtargetInfo &STI,
+                      raw_ostream &O);
 };
 } // end namespace llvm
 
Index: llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.cpp
===================================================================
--- llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.cpp
+++ llvm/trunk/lib/Target/Sparc/InstPrinter/SparcInstPrinter.cpp
@@ -195,3 +195,26 @@
   llvm_unreachable("FIXME: Implement SparcInstPrinter::printGetPCX.");
   return true;
 }
+
+void SparcInstPrinter::printMembarTag(const MCInst *MI, int opNum,
+                                      const MCSubtargetInfo &STI,
+                                      raw_ostream &O) {
+  static const char *const TagNames[] = {
+      "#LoadLoad",  "#StoreLoad", "#LoadStore", "#StoreStore",
+      "#Lookaside", "#MemIssue",  "#Sync"};
+
+  unsigned Imm = MI->getOperand(opNum).getImm();
+
+  if (Imm > 127) {
+    O << Imm;
+    return;
+  }
+
+  bool First = true;
+  for (unsigned i = 0; i < sizeof(TagNames) / sizeof(char *); i++) {
+    if (Imm & (1 << i)) {
+      O << (First ? "" : " | ") << TagNames[i];
+      First = false;
+    }
+  }
+}
Index: llvm/trunk/lib/Target/Sparc/SparcInstrInfo.td
===================================================================
--- llvm/trunk/lib/Target/Sparc/SparcInstrInfo.td
+++ llvm/trunk/lib/Target/Sparc/SparcInstrInfo.td
@@ -138,6 +138,16 @@
 
 def TLSSym : Operand<iPTR>;
 
+def SparcMembarTagAsmOperand : AsmOperandClass {
+  let Name = "MembarTag";
+  let ParserMethod = "parseMembarTag";
+}
+
+def MembarTag : Operand<i32> {
+  let PrintMethod = "printMembarTag";
+  let ParserMatchClass = SparcMembarTagAsmOperand;
+}
+
 // Branch targets have OtherVT type.
 def brtarget : Operand<OtherVT> {
   let EncoderMethod = "getBranchTargetOpValue";
@@ -1503,7 +1513,7 @@
           (POPCrr (SRLri $src, 0))>;
 
 let Predicates = [HasV9], hasSideEffects = 1, rd = 0, rs1 = 0b01111 in
- def MEMBARi : F3_2<2, 0b101000, (outs), (ins simm13Op:$simm13),
+ def MEMBARi : F3_2<2, 0b101000, (outs), (ins MembarTag:$simm13),
                     "membar $simm13", []>;
 
 // The CAS instruction, unlike other instructions, only comes in a 
Index: llvm/trunk/test/MC/Disassembler/Sparc/sparc-v9.txt
===================================================================
--- llvm/trunk/test/MC/Disassembler/Sparc/sparc-v9.txt
+++ llvm/trunk/test/MC/Disassembler/Sparc/sparc-v9.txt
@@ -115,4 +115,19 @@
 0x9f 0xd0 0x30 0x52
 
 # CHECK: tvs %xcc, %g1 + %i2   
-0x8f 0xd0 0x50 0x1a
\ No newline at end of file
+0x8f 0xd0 0x50 0x1a
+
+# CHECK: membar 5000
+0x81 0x43 0xf3 0x88
+
+# CHECK: membar #LoadLoad | #StoreLoad | #LoadStore | #StoreStore
+0x81 0x43 0xe0 0x0f
+
+# CHECK: membar #LoadLoad
+0x81 0x43 0xe0 0x01
+
+# CHECK: membar #LoadLoad | #StoreStore
+0x81 0x43 0xe0 0x09
+
+# CHECK: membar #LoadLoad | #StoreLoad | #LoadStore | #StoreStore | #Lookaside | #MemIssue | #Sync
+0x81 0x43 0xe0 0x7f
Index: llvm/trunk/test/MC/Sparc/sparc-asm-errors.s
===================================================================
--- llvm/trunk/test/MC/Sparc/sparc-asm-errors.s
+++ llvm/trunk/test/MC/Sparc/sparc-asm-errors.s
@@ -1,8 +1,16 @@
-! RUN: not llvm-mc %s -arch=sparc   -show-encoding 2>&1 | FileCheck %s
-! RUN: not llvm-mc %s -arch=sparcv9 -show-encoding 2>&1 | FileCheck %s
+! RUN: not llvm-mc %s -arch=sparc   -show-encoding 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=V8
+! RUN: not llvm-mc %s -arch=sparcv9 -show-encoding 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=V9
 
 ! Test the lower and upper bounds of 'set'
         ! CHECK: argument must be between
         set -2147483649, %o1
         ! CHECK: argument must be between
         set 4294967296, %o1
+
+        ! V8: unexpected token
+        ! V9: unknown membar tag
+        membar #BadTag
+
+        ! V8: instruction requires a CPU feature not currently enabled
+        ! V9: invalid membar mask number
+        membar -127
Index: llvm/trunk/test/MC/Sparc/sparcv9-atomic-instructions.s
===================================================================
--- llvm/trunk/test/MC/Sparc/sparcv9-atomic-instructions.s
+++ llvm/trunk/test/MC/Sparc/sparcv9-atomic-instructions.s
@@ -1,8 +1,17 @@
 ! RUN: llvm-mc %s -arch=sparcv9 -show-encoding | FileCheck %s
 
-        ! CHECK: membar 15             ! encoding: [0x81,0x43,0xe0,0x0f]
+        ! CHECK: membar #LoadLoad | #StoreLoad | #LoadStore | #StoreStore  ! encoding: [0x81,0x43,0xe0,0x0f]
         membar 15
 
+        ! CHECK: membar #LoadLoad  ! encoding: [0x81,0x43,0xe0,0x01]
+        membar #LoadLoad
+
+        ! CHECK: membar #LoadLoad | #StoreStore  ! encoding: [0x81,0x43,0xe0,0x09]
+        membar #LoadLoad | #StoreStore
+
+        ! CHECK: membar #LoadLoad | #StoreLoad | #LoadStore | #StoreStore | #Lookaside | #MemIssue | #Sync  ! encoding: [0x81,0x43,0xe0,0x7f]
+        membar #LoadLoad | #StoreLoad | #LoadStore | #StoreStore | #Lookaside | #MemIssue | #Sync
+
         ! CHECK: cas [%i0], %l6, %o2   ! encoding: [0xd5,0xe6,0x10,0x16]
         cas [%i0], %l6, %o2