diff --git a/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp b/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
index 20bb7951f91..6e0614ad6cf 100644
--- a/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
+++ b/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
@@ -374,12 +374,20 @@ void X86MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
   case X86::MOVZX64rm8:   LowerSubReg32_Op0(OutMI, X86::MOVZX32rm8); break;
   case X86::MOVZX64rr16:  LowerSubReg32_Op0(OutMI, X86::MOVZX32rr16); break;
   case X86::MOVZX64rm16:  LowerSubReg32_Op0(OutMI, X86::MOVZX32rm16); break;
-  case X86::MOV16r0:      LowerSubReg32_Op0(OutMI, X86::MOV32r0); break;
-  case X86::MOV64r0:      LowerSubReg32_Op0(OutMI, X86::MOV32r0); break;
   case X86::SETB_C8r:     LowerUnaryToTwoAddr(OutMI, X86::SBB8rr); break;
   case X86::SETB_C16r:    LowerUnaryToTwoAddr(OutMI, X86::SBB16rr); break;
   case X86::SETB_C32r:    LowerUnaryToTwoAddr(OutMI, X86::SBB32rr); break;
   case X86::SETB_C64r:    LowerUnaryToTwoAddr(OutMI, X86::SBB64rr); break;
+  case X86::MOV8r0:       LowerUnaryToTwoAddr(OutMI, X86::XOR8rr); break;
+  case X86::MOV32r0:      LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); break;
+  case X86::MOV16r0:
+    LowerSubReg32_Op0(OutMI, X86::MOV32r0);   // MOV16r0 -> MOV32r0
+    LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
+    break;
+  case X86::MOV64r0:
+    LowerSubReg32_Op0(OutMI, X86::MOV32r0);   // MOV64r0 -> MOV32r0
+    LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
+    break;
   }
 }
 
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 914978e75df..d604c176b15 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -3739,10 +3739,10 @@ let neverHasSideEffects = 1 in {
 
 // Alias instructions that map movr0 to xor.
 // FIXME: remove when we can teach regalloc that xor reg, reg is ok.
+// FIXME: Set encoding to pseudo.
 let Defs = [EFLAGS], isReMaterializable = 1, isAsCheapAsAMove = 1,
     isCodeGenOnly = 1 in {
-def MOV8r0   : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins),
-                 "xor{b}\t$dst, $dst",
+def MOV8r0   : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins), "",
                  [(set GR8:$dst, 0)]>;
 
 // We want to rewrite MOV16r0 in terms of MOV32r0, because it's a smaller
@@ -3754,8 +3754,8 @@ def MOV16r0   : I<0x31, MRMInitReg, (outs GR16:$dst), (ins),
                  "",
                  [(set GR16:$dst, 0)]>, OpSize;
                  
-def MOV32r0  : I<0x31, MRMInitReg, (outs GR32:$dst), (ins),
-                 "xor{l}\t$dst, $dst",
+// FIXME: Set encoding to pseudo.
+def MOV32r0  : I<0x31, MRMInitReg, (outs GR32:$dst), (ins), "",
                  [(set GR32:$dst, 0)]>;
 }