// checked.
// FIXME: Check AH, CH, DH, BH cannot be used in an instruction requiring a
// REX prefix.
- if (RegNo == X86::RIZ ||
+ if (RegNo == X86::RIZ || RegNo == X86::RIP || RegNo == X86::EIP ||
X86MCRegisterClasses[X86::GR64RegClassID].contains(RegNo) ||
X86II::isX86_64NonExtLowByteReg(RegNo) ||
X86II::isX86_64ExtendedReg(RegNo))