diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 212478c58ab..cf3c467ab64 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7803,7 +7803,7 @@ X86TargetLowering::EmitAtomicBit6432WithCustomInserter(MachineInstr *bInstr,
   for (int i=0; i < 2 + X86AddrNumOperands; ++i)
     argOpers[i] = &bInstr->getOperand(i+2);
 
-  // x86 address has 4 operands: base, index, scale, and displacement
+  // x86 address has 5 operands: base, index, scale, displacement, and segment.
   int lastAddrIndx = X86AddrNumOperands - 1; // [0,3]
 
   unsigned t1 = F->getRegInfo().createVirtualRegister(RC);