Index: llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.h
===================================================================
--- llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.h
+++ llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.h
@@ -62,7 +62,6 @@
 // - VariableIndex: the index of the Variable holding the value for this Operand
 // or -1 if this operand is implicit.
 struct Operand {
-  bool getIndex() const;
   bool isExplicit() const;
   bool isImplicit() const;
   bool isImplicitReg() const;
@@ -73,8 +72,9 @@
   bool isVariable() const;
   bool isMemory() const;
   bool isImmediate() const;
-  int getTiedToIndex() const;
-  int getVariableIndex() const;
+  unsigned getIndex() const;
+  unsigned getTiedToIndex() const;
+  unsigned getVariableIndex() const;
   unsigned getImplicitReg() const;
   const RegisterAliasingTracker &getRegisterAliasing() const;
   const llvm::MCOperandInfo &getExplicitOperandInfo() const;
@@ -118,6 +118,10 @@
   // aliasing Use and Def registers.
   bool hasAliasingRegisters() const;
 
+  // Convenient function to help with debugging.
+  void Dump(const llvm::MCRegisterInfo &RegInfo,
+            llvm::raw_ostream &Stream) const;
+
   const llvm::MCInstrDesc *Description; // Never nullptr.
   llvm::SmallVector<Operand, 8> Operands;
   llvm::SmallVector<Variable, 4> Variables;
Index: llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.cpp
===================================================================
--- llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.cpp
+++ llvm/trunk/tools/llvm-exegesis/lib/MCInstrDescView.cpp
@@ -29,7 +29,10 @@
 
 bool Variable::hasTiedOperands() const { return TiedOperands.size() > 1; }
 
-bool Operand::getIndex() const { return Index; }
+unsigned Operand::getIndex() const {
+  assert(Index >= 0 && "Index must be set");
+  return Index;
+}
 
 bool Operand::isExplicit() const { return Info; }
 
@@ -57,13 +60,15 @@
          getExplicitOperandInfo().OperandType == llvm::MCOI::OPERAND_IMMEDIATE;
 }
 
-int Operand::getTiedToIndex() const {
-  assert(isTied());
+unsigned Operand::getTiedToIndex() const {
+  assert(isTied() && "Operand must be tied to get the tied index");
+  assert(TiedToIndex >= 0 && "TiedToIndex must be set");
   return TiedToIndex;
 }
 
-int Operand::getVariableIndex() const {
-  assert(isVariable());
+unsigned Operand::getVariableIndex() const {
+  assert(isVariable() && "Operand must be variable to get the Variable index");
+  assert(VariableIndex >= 0 && "VariableIndex must be set");
   return VariableIndex;
 }
 
@@ -179,6 +184,51 @@
   return AllDefRegs.anyCommon(AllUseRegs);
 }
 
+void Instruction::Dump(const llvm::MCRegisterInfo &RegInfo,
+                       llvm::raw_ostream &Stream) const {
+  for (const auto &Op : Operands) {
+    Stream << "- Op" << Op.getIndex();
+    if (Op.isExplicit())
+      Stream << " Explicit";
+    if (Op.isImplicit())
+      Stream << " Implicit";
+    if (Op.isUse())
+      Stream << " Use";
+    if (Op.isDef())
+      Stream << " Def";
+    if (Op.isImmediate())
+      Stream << " Immediate";
+    if (Op.isMemory())
+      Stream << " Memory";
+    if (Op.isReg()) {
+      if (Op.isImplicitReg())
+        Stream << " Reg(" << RegInfo.getName(Op.getImplicitReg()) << ")";
+      else
+        Stream << " RegClass("
+               << RegInfo.getRegClassName(
+                      &RegInfo.getRegClass(Op.Info->RegClass))
+               << ")";
+    }
+    if (Op.isTied())
+      Stream << " TiedToOp" << Op.getTiedToIndex();
+    Stream << "\n";
+  }
+  for (const auto &Var : Variables) {
+    Stream << "- Var" << Var.getIndex();
+    for (auto OperandIndex : Var.TiedOperands)
+      Stream << " Op" << OperandIndex;
+    Stream << "\n";
+  }
+  if (hasMemoryOperands())
+    Stream << "- hasMemoryOperands\n";
+  if (hasAliasingImplicitRegisters())
+    Stream << "- hasAliasingImplicitRegisters (execution is always serial)\n";
+  if (hasTiedRegisters())
+    Stream << "- hasTiedRegisters (execution is always serial)\n";
+  if (hasAliasingRegisters())
+    Stream << "- hasAliasingRegisters\n";
+}
+
 bool RegisterOperandAssignment::
 operator==(const RegisterOperandAssignment &Other) const {
   return std::tie(Op, Reg) == std::tie(Other.Op, Other.Reg);