diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index f774d04ca67..041ae151c21 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -11899,24 +11899,6 @@ X86TargetLowering::EmitMonitor(MachineInstr *MI, MachineBasicBlock *BB) const {
   return BB;
 }
 
-MachineBasicBlock *
-X86TargetLowering::EmitMwait(MachineInstr *MI, MachineBasicBlock *BB) const {
-  DebugLoc dl = MI->getDebugLoc();
-  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
-
-  // First arg in ECX, the second in EAX.
-  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::ECX)
-    .addReg(MI->getOperand(0).getReg());
-  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::EAX)
-    .addReg(MI->getOperand(1).getReg());
-
-  // The instruction doesn't actually take any operands though.
-  BuildMI(*BB, MI, dl, TII->get(X86::MWAITrr));
-
-  MI->eraseFromParent(); // The pseudo is gone now.
-  return BB;
-}
-
 MachineBasicBlock *
 X86TargetLowering::EmitVAARG64WithCustomInserter(
                    MachineInstr *MI,
@@ -12721,8 +12703,6 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     // Thread synchronization.
   case X86::MONITOR:
     return EmitMonitor(MI, BB);
-  case X86::MWAIT:
-    return EmitMwait(MI, BB);
 
     // Atomic Lowering.
   case X86::ATOMAND32:
diff --git a/lib/Target/X86/X86InstrSSE.td b/lib/Target/X86/X86InstrSSE.td
index 897f1fe8c1b..edb7f6ccac4 100644
--- a/lib/Target/X86/X86InstrSSE.td
+++ b/lib/Target/X86/X86InstrSSE.td
@@ -5442,16 +5442,14 @@ let usesCustomInserter = 1 in {
 def MONITOR : PseudoI<(outs), (ins i32mem:$src1, GR32:$src2, GR32:$src3),
                 [(int_x86_sse3_monitor addr:$src1, GR32:$src2, GR32:$src3)]>,
                 Requires<[HasSSE3]>;
-def MWAIT : PseudoI<(outs), (ins GR32:$src1, GR32:$src2),
-                [(int_x86_sse3_mwait GR32:$src1, GR32:$src2)]>,
-                Requires<[HasSSE3]>;
 }
 
 let Uses = [EAX, ECX, EDX] in
 def MONITORrrr : I<0x01, MRM_C8, (outs), (ins), "monitor", [], IIC_SSE_MONITOR>,
                  TB, Requires<[HasSSE3]>;
 let Uses = [ECX, EAX] in
-def MWAITrr   : I<0x01, MRM_C9, (outs), (ins), "mwait", [], IIC_SSE_MWAIT>,
+def MWAITrr   : I<0x01, MRM_C9, (outs), (ins), "mwait",
+                [(int_x86_sse3_mwait ECX, EAX)], IIC_SSE_MWAIT>,
                 TB, Requires<[HasSSE3]>;
 
 def : InstAlias<"mwait %eax, %ecx", (MWAITrr)>, Requires<[In32BitMode]>;