diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 4d9e2bef742..a47dee3aeeb 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2732,7 +2732,7 @@ static unsigned getMemModRMByteSize(const MachineInstr &MI, unsigned Op,
   unsigned BaseReg = Base.getReg();
 
   // Is a SIB byte needed?
-  if (IndexReg.getReg() == 0 &&
+  if ((!Is64BitMode || DispForReloc) && IndexReg.getReg() == 0 &&
       (BaseReg == 0 || X86RegisterInfo::getX86RegNum(BaseReg) != N86::ESP)) {
     if (BaseReg == 0) {  // Just a displacement?
       // Emit special case [disp32] encoding