X86ISelLowering.cpp

         "Should use MaskedValueIsZero if you don't know whether Op"
         " is a target node!");

  KnownZero = KnownOne = 0;   // Don't know anything.
  switch (Opc) {
  default: break;
  case X86ISD::SETCC: 
    KnownZero |= (MVT::getIntVTBitMask(Op.getValueType()) ^ 1ULL);
    break;
  }
}

std::vector<unsigned> X86TargetLowering::
getRegClassForInlineAsmConstraint(const std::string &Constraint,
                                  MVT::ValueType VT) const {
  if (Constraint.size() == 1) {
    // FIXME: not handling fp-stack yet!
    // FIXME: not handling MMX registers yet ('y' constraint).
    switch (Constraint[0]) {      // GCC X86 Constraint Letters
    default: break;  // Unknown constriant letter
    case 'r':   // GENERAL_REGS
    case 'R':   // LEGACY_REGS
      return make_vector<unsigned>(X86::EAX, X86::EBX, X86::ECX, X86::EDX,
                                   X86::ESI, X86::EDI, X86::EBP, X86::ESP, 0);
    case 'l':   // INDEX_REGS
      return make_vector<unsigned>(X86::EAX, X86::EBX, X86::ECX, X86::EDX,
                                   X86::ESI, X86::EDI, X86::EBP, 0);
    case 'q':   // Q_REGS (GENERAL_REGS in 64-bit mode)
    case 'Q':   // Q_REGS
      return make_vector<unsigned>(X86::EAX, X86::EBX, X86::ECX, X86::EDX, 0);
    case 'x':   // SSE_REGS if SSE1 allowed
      if (Subtarget->hasSSE1())
        return make_vector<unsigned>(X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
                                     X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7,
                                     0);
      return std::vector<unsigned>();
    case 'Y':   // SSE_REGS if SSE2 allowed
      if (Subtarget->hasSSE2())
        return make_vector<unsigned>(X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
                                     X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7,
                                     0);
      return std::vector<unsigned>();
    }
  }
  
  return std::vector<unsigned>();
}

/// isLegalAddressImmediate - Return true if the integer value or
/// GlobalValue can be used as the offset of the target addressing mode.
bool X86TargetLowering::isLegalAddressImmediate(int64_t V) const {
  // X86 allows a sign-extended 32-bit immediate field.
  return (V > -(1LL << 32) && V < (1LL << 32)-1);
}

bool X86TargetLowering::isLegalAddressImmediate(GlobalValue *GV) const {
  if (Subtarget->isTargetDarwin()) {
    Reloc::Model RModel = getTargetMachine().getRelocationModel();
    if (RModel == Reloc::Static)
      return true;
    else if (RModel == Reloc::DynamicNoPIC)
      return !DarwinGVRequiresExtraLoad(GV);
    else
      return false;
  } else
    return true;
}

/// isShuffleMaskLegal - Targets can use this to indicate that they only
/// support *some* VECTOR_SHUFFLE operations, those with specific masks.
/// By default, if a target supports the VECTOR_SHUFFLE node, all mask values
/// are assumed to be legal.
bool
X86TargetLowering::isShuffleMaskLegal(SDOperand Mask, MVT::ValueType VT) const {
  // Only do shuffles on 128-bit vector types for now.
  if (MVT::getSizeInBits(VT) == 64) return false;
  return (Mask.Val->getNumOperands() == 2 ||
          X86::isSplatMask(Mask.Val) ||
          X86::isPSHUFDMask(Mask.Val) ||
          isPSHUFHW_PSHUFLWMask(Mask.Val) ||
          X86::isSHUFPMask(Mask.Val) ||
          X86::isUNPCKLMask(Mask.Val) ||
          X86::isUNPCKL_v_undef_Mask(Mask.Val) ||
          X86::isUNPCKHMask(Mask.Val));
}