diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index 7c153ece928..c18dff351f1 100644
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -18,6 +18,7 @@
 #include "Record.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/CommandLine.h"
+#include <set>
 using namespace llvm;
 
 static cl::opt<unsigned>
@@ -250,39 +251,48 @@ CodeGenInstruction::CodeGenInstruction(Record *R, const std::string &AsmStr)
   usesCustomDAGSchedInserter = R->getValueAsBit("usesCustomDAGSchedInserter");
   hasVariableNumberOfOperands = false;
   
+  DagInit *DI;
   try {
-    DagInit *DI = R->getValueAsDag("OperandList");
-
-    unsigned MIOperandNo = 0;
-    for (unsigned i = 0, e = DI->getNumArgs(); i != e; ++i)
-      if (DefInit *Arg = dynamic_cast<DefInit*>(DI->getArg(i))) {
-        Record *Rec = Arg->getDef();
-        MVT::ValueType Ty;
-        std::string PrintMethod = "printOperand";
-        unsigned NumOps = 1;
-        if (Rec->isSubClassOf("RegisterClass")) {
-          Ty = getValueType(Rec->getValueAsDef("RegType"));
-        } else if (Rec->isSubClassOf("Operand")) {
-          Ty = getValueType(Rec->getValueAsDef("Type"));
-          PrintMethod = Rec->getValueAsString("PrintMethod");
-          NumOps = Rec->getValueAsInt("NumMIOperands");
-        } else if (Rec->getName() == "variable_ops") {
-          hasVariableNumberOfOperands = true;
-          continue;
-        } else
-          throw "Unknown operand class '" + Rec->getName() +
-                "' in instruction '" + R->getName() + "' instruction!";
-
-        OperandList.push_back(OperandInfo(Rec, Ty, DI->getArgName(i),
-                                          PrintMethod, MIOperandNo, NumOps));
-        MIOperandNo += NumOps;
-      } else {
-        throw "Illegal operand for the '" + R->getName() + "' instruction!";
-      }
+    DI = R->getValueAsDag("OperandList");
   } catch (...) {
-    // Error parsing operands list, just ignore it.
+    // Error getting operand list, just ignore it (sparcv9).
     AsmString.clear();
     OperandList.clear();
+    return;
+  }
+
+  unsigned MIOperandNo = 0;
+  std::set<std::string> OperandNames;
+  for (unsigned i = 0, e = DI->getNumArgs(); i != e; ++i) {
+    DefInit *Arg = dynamic_cast<DefInit*>(DI->getArg(i));
+    if (!Arg)
+      throw "Illegal operand for the '" + R->getName() + "' instruction!";
+
+    Record *Rec = Arg->getDef();
+    MVT::ValueType Ty;
+    std::string PrintMethod = "printOperand";
+    unsigned NumOps = 1;
+    if (Rec->isSubClassOf("RegisterClass")) {
+      Ty = getValueType(Rec->getValueAsDef("RegType"));
+    } else if (Rec->isSubClassOf("Operand")) {
+      Ty = getValueType(Rec->getValueAsDef("Type"));
+      PrintMethod = Rec->getValueAsString("PrintMethod");
+      NumOps = Rec->getValueAsInt("NumMIOperands");
+    } else if (Rec->getName() == "variable_ops") {
+      hasVariableNumberOfOperands = true;
+      continue;
+    } else
+      throw "Unknown operand class '" + Rec->getName() +
+            "' in instruction '" + R->getName() + "' instruction!";
+
+    if (!DI->getArgName(i).empty() && 
+        !OperandNames.insert(DI->getArgName(i)).second)
+      throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
+        " has the same name as a previous operand!";
+    
+    OperandList.push_back(OperandInfo(Rec, Ty, DI->getArgName(i),
+                                      PrintMethod, MIOperandNo, NumOps));
+    MIOperandNo += NumOps;
   }
 }