diff --git a/include/llvm/CodeGen/MachineInstr.h b/include/llvm/CodeGen/MachineInstr.h
index b5bb25a4b3a..5c5207fb56d 100644
--- a/include/llvm/CodeGen/MachineInstr.h
+++ b/include/llvm/CodeGen/MachineInstr.h
@@ -225,8 +225,8 @@ class MachineInstr : public Annotable,         // MachineInstrs are annotable
   // OperandComplete - Return true if it's illegal to add a new operand
   bool OperandsComplete() const;
 public:
-  MachineInstr(MachineOpCode Opcode, OpCodeMask OpcodeMask = 0);
-  MachineInstr(MachineOpCode Opcode, unsigned numOperands, OpCodeMask Mask = 0);
+  MachineInstr(MachineOpCode Opcode);
+  MachineInstr(MachineOpCode Opcode, unsigned numOperands);
 
   /// MachineInstr ctor - This constructor only does a _reserve_ of the
   /// operands, not a resize for them.  It is expected that if you use this that
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 2a1893cc3d0..85d3f1a8f26 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -9,20 +9,24 @@ using std::cerr;
 
 
 // Constructor for instructions with fixed #operands (nearly all)
-MachineInstr::MachineInstr(MachineOpCode _opCode,
-			   OpCodeMask    _opCodeMask)
-  : opCode(_opCode), opCodeMask(_opCodeMask),
+MachineInstr::MachineInstr(MachineOpCode _opCode)
+  : opCode(_opCode), opCodeMask(0),
     operands(TargetInstrDescriptors[_opCode].numOperands, MachineOperand()) {
   assert(TargetInstrDescriptors[_opCode].numOperands >= 0);
 }
 
 // Constructor for instructions with variable #operands
-MachineInstr::MachineInstr(MachineOpCode OpCode, unsigned  numOperands,
-			   OpCodeMask    OpCodeMask)
-  : opCode(OpCode), opCodeMask(OpCodeMask),
+MachineInstr::MachineInstr(MachineOpCode OpCode, unsigned  numOperands/*,
+                                                                        OpCodeMask    OpCodeMask*/)
+  : opCode(OpCode), opCodeMask(0/*OpCodeMask*/),
     operands(numOperands, MachineOperand()) {
 }
 
+MachineInstr::MachineInstr(MachineOpCode Opcode, unsigned numOperands,
+                           bool XX, bool YY) : opCode(Opcode), opCodeMask(0) {
+  operands.reserve(numOperands);
+}
+
 // OperandComplete - Return true if it's illegal to add a new operand
 bool MachineInstr::OperandsComplete() const {
   int NumOperands = TargetInstrDescriptors[opCode].numOperands;