diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 201b79e..8d8e9b7 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -52,7 +52,7 @@
 
 
 MachineInstr* ilist_traits<MachineInstr>::createSentinel() {
-  MachineInstr* dummy = new MachineInstr(0, 0);
+  MachineInstr* dummy = new MachineInstr();
   LeakDetector::removeGarbageObject(dummy);
   return dummy;
 }
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 16e235a..bafdffb 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -32,14 +32,10 @@
   extern const TargetInstrDescriptor *TargetInstrDescriptors;
 }
 
-/// 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 you call
-/// add* methods below to fill up the operands, instead of the Set methods.
-/// Eventually, the "resizing" ctors will be phased out.
-///
-MachineInstr::MachineInstr(short opcode, unsigned numOperands)
-  : Opcode(opcode), NumImplicitOps(0), parent(0) {
-  Operands.reserve(numOperands);
+/// MachineInstr ctor - This constructor creates a dummy MachineInstr with
+/// opcode 0 and no operands.
+MachineInstr::MachineInstr()
+  : Opcode(0), NumImplicitOps(0), parent(0) {
   // Make sure that we get added to a machine basicblock
   LeakDetector::addGarbageObject(this);
 }
@@ -72,18 +68,18 @@
 }
 
 /// MachineInstr ctor - This constructor create a MachineInstr and add the
-/// implicit operands. It reserves space for numOperand operands.
-MachineInstr::MachineInstr(const TargetInstrInfo &TII, short opcode,
-                           unsigned numOperands)
-  : Opcode(opcode), NumImplicitOps(0), parent(0) {
-  const TargetInstrDescriptor &TID = TII.get(opcode);
+/// implicit operands. It reserves space for number of operands specified by
+/// TargetInstrDescriptor or the numOperands if it is not zero. (for
+/// instructions with variable number of operands).
+MachineInstr::MachineInstr(const TargetInstrDescriptor &TID)
+  : Opcode(TID.Opcode), NumImplicitOps(0), parent(0) {
   if (TID.ImplicitDefs)
     for (const unsigned *ImpDefs = TID.ImplicitDefs; *ImpDefs; ++ImpDefs)
       NumImplicitOps++;
   if (TID.ImplicitUses)
     for (const unsigned *ImpUses = TID.ImplicitUses; *ImpUses; ++ImpUses)
       NumImplicitOps++;
-  Operands.reserve(NumImplicitOps + numOperands);
+  Operands.reserve(NumImplicitOps + TID.numOperands);
   addImplicitDefUseOperands(TID);
   // Make sure that we get added to a machine basicblock
   LeakDetector::addGarbageObject(this);
@@ -92,19 +88,17 @@
 /// MachineInstr ctor - Work exactly the same as the ctor above, except that the
 /// MachineInstr is created and added to the end of the specified basic block.
 ///
-MachineInstr::MachineInstr(MachineBasicBlock *MBB, short opcode,
-                           unsigned numOperands)
-  : Opcode(opcode), NumImplicitOps(0), parent(0) {
+MachineInstr::MachineInstr(MachineBasicBlock *MBB,
+                           const TargetInstrDescriptor &TID)
+  : Opcode(TID.Opcode), NumImplicitOps(0), parent(0) {
   assert(MBB && "Cannot use inserting ctor with null basic block!");
-  const TargetInstrDescriptor &TID = MBB->getParent()->getTarget().
-    getInstrInfo()->get(opcode);
   if (TID.ImplicitDefs)
     for (const unsigned *ImpDefs = TID.ImplicitDefs; *ImpDefs; ++ImpDefs)
       NumImplicitOps++;
   if (TID.ImplicitUses)
     for (const unsigned *ImpUses = TID.ImplicitUses; *ImpUses; ++ImpUses)
       NumImplicitOps++;
-  Operands.reserve(NumImplicitOps + numOperands);
+  Operands.reserve(NumImplicitOps + TID.numOperands);
   addImplicitDefUseOperands(TID);
   // Make sure that we get added to a machine basicblock
   LeakDetector::addGarbageObject(this);
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index 5330306..e72cdc6 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -395,7 +395,7 @@
 #endif
 
     // Create the new machine instruction.
-    MachineInstr *MI = new MachineInstr(*TII, Opc, NumMIOperands);
+    MachineInstr *MI = new MachineInstr(II);
     
     // Add result register values for things that are defined by this
     // instruction.
@@ -518,7 +518,7 @@
       
       // Create the inline asm machine instruction.
       MachineInstr *MI =
-        new MachineInstr(BB, TargetInstrInfo::INLINEASM, (NumOps-2)/2+1);
+        new MachineInstr(BB, TII->get(TargetInstrInfo::INLINEASM));
 
       // Add the asm string as an external symbol operand.
       const char *AsmStr =
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index c18b5bc..0257e1b 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -294,8 +294,9 @@
       }
       unsigned PHIReg = ValueMap[PN];
       assert(PHIReg && "PHI node does not have an assigned virtual register!");
+      const TargetInstrInfo *TII = TLI.getTargetMachine().getInstrInfo();
       for (unsigned i = 0; i != NumElements; ++i)
-        BuildMI(MBB, TargetInstrInfo::PHI, PN->getNumOperands(), PHIReg+i);
+        BuildMI(MBB, TII->get(TargetInstrInfo::PHI), PHIReg+i);
     }
   }
 }