diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 8c28c97..17144f5 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -187,7 +187,7 @@
               MRegisterInfo::isVirtualRegister(mop.getReg())) {
             // replace register with representative register
             unsigned reg = rep(mop.getReg());
-            mii->SetMachineOperandReg(i, reg);
+            mii->getOperand(i).setReg(reg);
 
             LiveInterval &RegInt = getInterval(reg);
             RegInt.weight +=
@@ -263,7 +263,7 @@
           if (NewRegLiveIn && mop.isUse()) {
             // We already emitted a reload of this value, reuse it for
             // subsequent operands.
-            MI->SetMachineOperandReg(i, NewRegLiveIn);
+            MI->getOperand(i).setReg(NewRegLiveIn);
             DEBUG(std::cerr << "\t\t\t\treused reload into reg" << NewRegLiveIn
                             << " for operand #" << i << '\n');
           } else if (MachineInstr* fmi = mri_->foldMemoryOperand(MI, i, slot)) {
@@ -300,7 +300,7 @@
 
             // create a new register for this spill
             NewRegLiveIn = mf_->getSSARegMap()->createVirtualRegister(rc);
-            MI->SetMachineOperandReg(i, NewRegLiveIn);
+            MI->getOperand(i).setReg(NewRegLiveIn);
             vrm.grow();
             vrm.assignVirt2StackSlot(NewRegLiveIn, slot);
             LiveInterval& nI = getOrCreateInterval(NewRegLiveIn);
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 90cec5a..b1fb52a 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -107,25 +107,6 @@
   return false;
 }
 
-void
-MachineInstr::SetMachineOperandConst(unsigned i,
-                                     MachineOperand::MachineOperandType opTy,
-                                     int intValue) {
-  assert(i < getNumOperands());
-  operands[i].opType = opTy;
-  operands[i].contents.immedVal = intValue;
-  operands[i].extra.regNum = -1;
-  operands[i].flags = 0;
-}
-
-void MachineInstr::SetMachineOperandReg(unsigned i, int regNum) {
-  assert(i < getNumOperands());
-
-  operands[i].opType = MachineOperand::MO_VirtualRegister;
-  operands[i].contents.GV = NULL;
-  operands[i].extra.regNum = regNum;
-}
-
 void MachineInstr::dump() const {
   std::cerr << "  " << *this;
 }
diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp
index f84f7e8..e3921e4 100644
--- a/lib/CodeGen/RegAllocLocal.cpp
+++ b/lib/CodeGen/RegAllocLocal.cpp
@@ -443,7 +443,7 @@
   // and return.
   if (unsigned PR = getVirt2PhysRegMapSlot(VirtReg)) {
     MarkPhysRegRecentlyUsed(PR);          // Already have this value available!
-    MI->SetMachineOperandReg(OpNum, PR);  // Assign the input register
+    MI->getOperand(OpNum).setReg(PR);  // Assign the input register
     return MI;
   }
 
@@ -481,7 +481,7 @@
   ++NumLoads;    // Update statistics
 
   PhysRegsEverUsed[PhysReg] = true;
-  MI->SetMachineOperandReg(OpNum, PhysReg);  // Assign the input register
+  MI->getOperand(OpNum).setReg(PhysReg);  // Assign the input register
   return MI;
 }
 
@@ -599,7 +599,7 @@
           DestPhysReg = getReg(MBB, MI, DestVirtReg);
         PhysRegsEverUsed[DestPhysReg] = true;
         markVirtRegModified(DestVirtReg);
-        MI->SetMachineOperandReg(i, DestPhysReg);  // Assign the output register
+        MI->getOperand(i).setReg(DestPhysReg);  // Assign the output register
       }
     }
 
diff --git a/lib/CodeGen/RegAllocSimple.cpp b/lib/CodeGen/RegAllocSimple.cpp
index f6a9a11..4e6e1d2 100644
--- a/lib/CodeGen/RegAllocSimple.cpp
+++ b/lib/CodeGen/RegAllocSimple.cpp
@@ -211,7 +211,7 @@
             Virt2PhysRegMap[virtualReg] = physReg;
           }
         }
-        MI->SetMachineOperandReg(i, physReg);
+        MI->getOperand(i).setReg(physReg);
         DEBUG(std::cerr << "virt: " << virtualReg <<
               ", phys: " << op.getReg() << "\n");
       }
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 48581ee..4bd2047 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -200,7 +200,7 @@
         for (unsigned i = 1, e = mi->getNumOperands(); i != e; ++i) {
           if (mi->getOperand(i).isRegister() &&
               mi->getOperand(i).getReg() == regB)
-            mi->SetMachineOperandReg(i, regA);
+            mi->getOperand(i).setReg(regA);
         }
       }
 
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index 912359d..533a53b 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -182,7 +182,7 @@
               }
             }
             PhysRegsUsed[PhysReg] = true;
-            MI.SetMachineOperandReg(i, PhysReg);
+            MI.getOperand(i).setReg(PhysReg);
           } else {
             PhysRegsUsed[MO.getReg()] = true;
           }
@@ -458,7 +458,7 @@
             // Any stores to this stack slot are not dead anymore.
             MaybeDeadStores.erase(NewOp.StackSlot);
             
-            MI->SetMachineOperandReg(NewOp.Operand, NewPhysReg);
+            MI->getOperand(NewOp.Operand).setReg(NewPhysReg);
             
             Spills.addAvailable(NewOp.StackSlot, NewPhysReg);
             ++NumLoads;
@@ -536,7 +536,7 @@
         // This virtual register was assigned a physreg!
         unsigned Phys = VRM.getPhys(VirtReg);
         PhysRegsUsed[Phys] = true;
-        MI.SetMachineOperandReg(i, Phys);
+        MI.getOperand(i).setReg(Phys);
         continue;
       }
       
@@ -567,7 +567,7 @@
                           << MRI->getName(PhysReg) << " for vreg"
                           << VirtReg <<" instead of reloading into physreg "
                           << MRI->getName(VRM.getPhys(VirtReg)) << "\n");
-          MI.SetMachineOperandReg(i, PhysReg);
+          MI.getOperand(i).setReg(PhysReg);
 
           // The only technical detail we have is that we don't know that
           // PhysReg won't be clobbered by a reloaded stack slot that occurs
@@ -618,7 +618,7 @@
                           << MRI->getName(PhysReg) << " for vreg"
                           << VirtReg
                           << " instead of reloading into same physreg.\n");
-          MI.SetMachineOperandReg(i, PhysReg);
+          MI.getOperand(i).setReg(PhysReg);
           ++NumReused;
           continue;
         }
@@ -633,7 +633,7 @@
         Spills.ClobberPhysReg(DesignatedReg);
         
         Spills.addAvailable(StackSlot, DesignatedReg);
-        MI.SetMachineOperandReg(i, DesignatedReg);
+        MI.getOperand(i).setReg(DesignatedReg);
         DEBUG(std::cerr << '\t' << *prior(MII));
         ++NumReused;
         continue;
@@ -662,7 +662,7 @@
       MaybeDeadStores.erase(StackSlot);
       Spills.addAvailable(StackSlot, PhysReg);
       ++NumLoads;
-      MI.SetMachineOperandReg(i, PhysReg);
+      MI.getOperand(i).setReg(PhysReg);
       DEBUG(std::cerr << '\t' << *prior(MII));
     }
 
@@ -817,7 +817,7 @@
         PhysRegsUsed[PhysReg] = true;
         MRI->storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC);
         DEBUG(std::cerr << "Store:\t" << *next(MII));
-        MI.SetMachineOperandReg(i, PhysReg);
+        MI.getOperand(i).setReg(PhysReg);
 
         // Check to see if this is a noop copy.  If so, eliminate the
         // instruction before considering the dest reg to be changed.
diff --git a/lib/Target/Alpha/AlphaRegisterInfo.cpp b/lib/Target/Alpha/AlphaRegisterInfo.cpp
index 95f60ed..55a98aa 100644
--- a/lib/Target/Alpha/AlphaRegisterInfo.cpp
+++ b/lib/Target/Alpha/AlphaRegisterInfo.cpp
@@ -216,7 +216,7 @@
   int FrameIndex = MI.getOperand(i).getFrameIndex();
 
   // Add the base register of R30 (SP) or R15 (FP).
-  MI.SetMachineOperandReg(i + 1, FP ? Alpha::R15 : Alpha::R30);
+  MI.getOperand(i + 1).ChangeToRegister(FP ? Alpha::R15 : Alpha::R30);
 
   // Now add the frame object offset to the offset from the virtual frame index.
   int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
@@ -233,15 +233,14 @@
     //so in this case, we need to use a temporary register, and move the original
     //inst off the SP/FP
     //fix up the old:
-    MI.SetMachineOperandReg(i + 1, Alpha::R28);
-    MI.SetMachineOperandConst(i, MachineOperand::MO_Immediate,
-                              getLower16(Offset));
+    MI.getOperand(i + 1).ChangeToRegister(Alpha::R28);
+    MI.getOperand(i).ChangeToImmediate(getLower16(Offset));
     //insert the new
     MachineInstr* nMI=BuildMI(Alpha::LDAH, 2, Alpha::R28)
       .addImm(getUpper16(Offset)).addReg(FP ? Alpha::R15 : Alpha::R30);
     MBB.insert(II, nMI);
   } else {
-    MI.SetMachineOperandConst(i, MachineOperand::MO_Immediate, Offset);
+    MI.getOperand(i).ChangeToImmediate(Offset);
   }
 }
 
diff --git a/lib/Target/IA64/IA64RegisterInfo.cpp b/lib/Target/IA64/IA64RegisterInfo.cpp
index 53fec20..9319212 100644
--- a/lib/Target/IA64/IA64RegisterInfo.cpp
+++ b/lib/Target/IA64/IA64RegisterInfo.cpp
@@ -155,7 +155,7 @@
   // choose a base register: ( hasFP? framepointer : stack pointer )
   unsigned BaseRegister = FP ? IA64::r5 : IA64::r12;
   // Add the base register
-  MI.SetMachineOperandReg(i, BaseRegister);
+  MI.getOperand(i).ChangeToRegister(BaseRegister);
 
   // Now add the frame object offset to the offset from r1.
   int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
@@ -168,7 +168,7 @@
   // XXX: we use 'r22' as another hack+slash temporary register here :(
   if ( Offset <= 8191 && Offset >= -8192) { // smallish offset
     //fix up the old:
-    MI.SetMachineOperandReg(i, IA64::r22);
+    MI.getOperand(i).ChangeToRegister(IA64::r22);
     MI.getOperand(i).setUse(); // mark r22 as being used
                                // (the bundler wants to know this)
     //insert the new
@@ -177,7 +177,7 @@
     MBB.insert(II, nMI);
   } else { // it's big
     //fix up the old:
-    MI.SetMachineOperandReg(i, IA64::r22);
+    MI.getOperand(i).ChangeToRegister(IA64::r22);
     MI.getOperand(i).setUse(); // mark r22 as being used
                                // (the bundler wants to know this)
     MachineInstr* nMI;
diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index 037928f..d71f357 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -136,8 +136,8 @@
   // Swap op1/op2
   unsigned Reg1 = MI->getOperand(1).getReg();
   unsigned Reg2 = MI->getOperand(2).getReg();
-  MI->SetMachineOperandReg(2, Reg1);
-  MI->SetMachineOperandReg(1, Reg2);
+  MI->getOperand(2).setReg(Reg1);
+  MI->getOperand(1).setReg(Reg2);
   
   // Swap the mask around.
   unsigned MB = MI->getOperand(4).getImmedValue();
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 24da5a3..36cb869 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -294,7 +294,7 @@
   int FrameIndex = MI.getOperand(i).getFrameIndex();
 
   // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
-  MI.SetMachineOperandReg(i, hasFP(MF) ? PPC::R31 : PPC::R1);
+  MI.getOperand(i).ChangeToRegister(hasFP(MF) ? PPC::R31 : PPC::R1);
 
   // Take into account whether it's an add or mem instruction
   unsigned OffIdx = (i == 2) ? 1 : 2;
@@ -321,8 +321,8 @@
            "No indexed form of load or store available!");
     unsigned NewOpcode = ImmToIdxMap.find(MI.getOpcode())->second;
     MI.setOpcode(NewOpcode);
-    MI.SetMachineOperandReg(1, MI.getOperand(i).getReg());
-    MI.SetMachineOperandReg(2, PPC::R0);
+    MI.getOperand(1).ChangeToRegister(MI.getOperand(i).getReg());
+    MI.getOperand(2).ChangeToRegister(PPC::R0);
   } else {
     switch (MI.getOpcode()) {
     case PPC::LWA:
@@ -333,7 +333,7 @@
       Offset >>= 2;    // The actual encoded value has the low two bits zero.
       break;
     }
-    MI.SetMachineOperandConst(OffIdx, MachineOperand::MO_Immediate, Offset);
+    MI.getOperand(OffIdx).ChangeToImmediate(Offset);
   }
 }
 
diff --git a/lib/Target/Sparc/FPMover.cpp b/lib/Target/Sparc/FPMover.cpp
index 70f203c..7073260 100644
--- a/lib/Target/Sparc/FPMover.cpp
+++ b/lib/Target/Sparc/FPMover.cpp
@@ -104,8 +104,8 @@
       else
         assert(0 && "Unknown opcode!");
         
-      MI->SetMachineOperandReg(0, EvenDestReg);
-      MI->SetMachineOperandReg(1, EvenSrcReg);
+      MI->getOperand(0).setReg(EvenDestReg);
+      MI->getOperand(1).setReg(EvenSrcReg);
       DEBUG(std::cerr << "FPMover: the modified instr is: " << *MI);
       // Insert copy for the other half of the double.
       if (DestDReg != SrcDReg) {
diff --git a/lib/Target/Sparc/SparcRegisterInfo.cpp b/lib/Target/Sparc/SparcRegisterInfo.cpp
index d72ca74..88cbc9c 100644
--- a/lib/Target/Sparc/SparcRegisterInfo.cpp
+++ b/lib/Target/Sparc/SparcRegisterInfo.cpp
@@ -135,8 +135,8 @@
   if (Offset >= -4096 && Offset <= 4095) {
     // If the offset is small enough to fit in the immediate field, directly
     // encode it.
-    MI.SetMachineOperandReg(i, SP::I6);
-    MI.SetMachineOperandConst(i+1, MachineOperand::MO_Immediate, Offset);
+    MI.getOperand(i).ChangeToRegister(SP::I6);
+    MI.getOperand(i+1).ChangeToImmediate(Offset);
   } else {
     // Otherwise, emit a G1 = SETHI %hi(offset).  FIXME: it would be better to 
     // scavenge a register here instead of reserving G1 all of the time.
@@ -146,9 +146,8 @@
     BuildMI(*MI.getParent(), II, SP::ADDrr, 2, 
             SP::G1).addReg(SP::G1).addReg(SP::I6);
     // Insert: G1+%lo(offset) into the user.
-    MI.SetMachineOperandReg(i, SP::G1);
-    MI.SetMachineOperandConst(i+1, MachineOperand::MO_Immediate,
-                              Offset & ((1 << 10)-1));
+    MI.getOperand(i).ChangeToRegister(SP::G1);
+    MI.getOperand(i+1).ChangeToImmediate(Offset & ((1 << 10)-1));
   }
 }
 
diff --git a/lib/Target/TargetInstrInfo.cpp b/lib/Target/TargetInstrInfo.cpp
index 60dd28c..6377de8 100644
--- a/lib/Target/TargetInstrInfo.cpp
+++ b/lib/Target/TargetInstrInfo.cpp
@@ -46,7 +46,7 @@
          "This only knows how to commute register operands so far");
   unsigned Reg1 = MI->getOperand(1).getReg();
   unsigned Reg2 = MI->getOperand(1).getReg();
-  MI->SetMachineOperandReg(2, Reg1);
-  MI->SetMachineOperandReg(1, Reg2);
+  MI->getOperand(2).setReg(Reg1);
+  MI->getOperand(1).setReg(Reg2);
   return MI;
 }
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 9f4a561..e34b511 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -665,7 +665,7 @@
 
   // This must be part of a four operand memory reference.  Replace the
   // FrameIndex with base register with EBP.  Add add an offset to the offset.
-  MI.SetMachineOperandReg(i, hasFP(MF) ? X86::EBP : X86::ESP);
+  MI.getOperand(i).ChangeToRegister(hasFP(MF) ? X86::EBP : X86::ESP);
 
   // Now add the frame object offset to the offset from EBP.
   int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
@@ -676,7 +676,7 @@
   else
     Offset += 4;  // Skip the saved EBP
 
-  MI.SetMachineOperandConst(i+3, MachineOperand::MO_Immediate, Offset);
+  MI.getOperand(i+3).ChangeToImmediate(Offset);
 }
 
 void