X86ISelLowering.cpp

      SDOperand RegToPass = RegValuesToPass[i];
      switch (RegToPass.getValueType()) {
      default: assert(0 && "Bad thing to pass in regs");
      case MVT::i8:
        CCReg = (i == 0) ? X86::AL  : X86::DL;
        break;
      case MVT::i16:
        CCReg = (i == 0) ? X86::AX  : X86::DX;
        break;
      case MVT::i32:
        CCReg = (i == 0) ? X86::EAX : X86::EDX;
        break;
      }

      Chain = DAG.getCopyToReg(Chain, CCReg, RegToPass, InFlag);
      InFlag = Chain.getValue(1);
    }

    std::vector<MVT::ValueType> NodeTys;
    NodeTys.push_back(MVT::Other);   // Returns a chain
    NodeTys.push_back(MVT::Flag);    // Returns a flag for retval copy to use.
    std::vector<SDOperand> Ops;
    Ops.push_back(Chain);
    Ops.push_back(Callee);
    if (InFlag.Val)
      Ops.push_back(InFlag);

    // FIXME: Do not generate X86ISD::TAILCALL for now.
    Chain = DAG.getNode(X86ISD::CALL, NodeTys, Ops);
    InFlag = Chain.getValue(1);

    NodeTys.clear();
    NodeTys.push_back(MVT::Other);   // Returns a chain
    NodeTys.push_back(MVT::Flag);    // Returns a flag for retval copy to use.
    Ops.clear();
    Ops.push_back(Chain);
    Ops.push_back(DAG.getConstant(ArgOffset, getPointerTy()));
    Ops.push_back(DAG.getConstant(ArgOffset, getPointerTy()));
    Ops.push_back(InFlag);
    Chain = DAG.getNode(ISD::CALLSEQ_END, NodeTys, Ops);
    InFlag = Chain.getValue(1);
    
    SDOperand RetVal;
    if (RetTyVT != MVT::isVoid) {
      switch (RetTyVT) {
      default: assert(0 && "Unknown value type to return!");
      case MVT::i1:
      case MVT::i8:
        RetVal = DAG.getCopyFromReg(Chain, X86::AL, MVT::i8, InFlag);
        Chain = RetVal.getValue(1);
        if (RetTyVT == MVT::i1) 
          RetVal = DAG.getNode(ISD::TRUNCATE, MVT::i1, RetVal);
        break;
      case MVT::i16:
        RetVal = DAG.getCopyFromReg(Chain, X86::AX, MVT::i16, InFlag);
        Chain = RetVal.getValue(1);
        break;
      case MVT::i32:
        RetVal = DAG.getCopyFromReg(Chain, X86::EAX, MVT::i32, InFlag);
        Chain = RetVal.getValue(1);
        break;
      case MVT::i64: {
        SDOperand Lo = DAG.getCopyFromReg(Chain, X86::EAX, MVT::i32, InFlag);
        SDOperand Hi = DAG.getCopyFromReg(Lo.getValue(1), X86::EDX, MVT::i32, 
                                          Lo.getValue(2));
        RetVal = DAG.getNode(ISD::BUILD_PAIR, MVT::i64, Lo, Hi);
        Chain = Hi.getValue(1);
        break;
      }
      case MVT::f32:
      case MVT::f64: {
        std::vector<MVT::ValueType> Tys;
        Tys.push_back(MVT::f64);
        Tys.push_back(MVT::Other);
        Tys.push_back(MVT::Flag);
        std::vector<SDOperand> Ops;
        Ops.push_back(Chain);
        Ops.push_back(InFlag);
        RetVal = DAG.getNode(X86ISD::FP_GET_RESULT, Tys, Ops);
        Chain  = RetVal.getValue(1);
        InFlag = RetVal.getValue(2);
        if (X86ScalarSSE) {
          // FIXME:Currently the FST is flagged to the FP_GET_RESULT. This
          // shouldn't be necessary except for RFP cannot be live across
          // multiple blocks. When stackifier is fixed, they can be uncoupled.
          unsigned Size = MVT::getSizeInBits(MVT::f64)/8;
          MachineFunction &MF = DAG.getMachineFunction();
          int SSFI = MF.getFrameInfo()->CreateStackObject(Size, Size);
          SDOperand StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
          Tys.clear();
          Tys.push_back(MVT::Other);
          Ops.clear();
          Ops.push_back(Chain);
          Ops.push_back(RetVal);
          Ops.push_back(StackSlot);
          Ops.push_back(DAG.getValueType(RetTyVT));
          Ops.push_back(InFlag);
          Chain = DAG.getNode(X86ISD::FST, Tys, Ops);
          RetVal = DAG.getLoad(RetTyVT, Chain, StackSlot,
                               DAG.getSrcValue(NULL));
          Chain = RetVal.getValue(1);
        }

        if (RetTyVT == MVT::f32 && !X86ScalarSSE)
          // FIXME: we would really like to remember that this FP_ROUND
          // operation is okay to eliminate if we allow excess FP precision.
          RetVal = DAG.getNode(ISD::FP_ROUND, MVT::f32, RetVal);
        break;
      }
      }
    }

    return std::make_pair(RetVal, Chain);
  } else {
    std::vector<SDOperand> Ops;
    Ops.push_back(Chain);
    Ops.push_back(Callee);
    Ops.push_back(DAG.getConstant(ArgOffset, getPointerTy()));
    // Callee pops all arg values on the stack.
    Ops.push_back(DAG.getConstant(ArgOffset, getPointerTy()));

    // Pass register arguments as needed.
    Ops.insert(Ops.end(), RegValuesToPass.begin(), RegValuesToPass.end());

    SDOperand TheCall = DAG.getNode(isTailCall ? X86ISD::TAILCALL : X86ISD::CALL,
                                    RetVals, Ops);
    Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, TheCall);

    SDOperand ResultVal;
    switch (RetTyVT) {
    case MVT::isVoid: break;
    default:
      ResultVal = TheCall.getValue(1);
      break;
    case MVT::i1:
    case MVT::i8:
    case MVT::i16:
      ResultVal = DAG.getNode(ISD::TRUNCATE, RetTyVT, TheCall.getValue(1));
      break;
    case MVT::f32:
      // FIXME: we would really like to remember that this FP_ROUND operation is
      // okay to eliminate if we allow excess FP precision.
      ResultVal = DAG.getNode(ISD::FP_ROUND, MVT::f32, TheCall.getValue(1));
      break;
    case MVT::i64:
      ResultVal = DAG.getNode(ISD::BUILD_PAIR, MVT::i64, TheCall.getValue(1),
                              TheCall.getValue(2));
      break;
    }

    return std::make_pair(ResultVal, Chain);
  }
}

SDOperand X86TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) {
  if (ReturnAddrIndex == 0) {
    // Set up a frame object for the return address.
    MachineFunction &MF = DAG.getMachineFunction();
    ReturnAddrIndex = MF.getFrameInfo()->CreateFixedObject(4, -4);
  }

  return DAG.getFrameIndex(ReturnAddrIndex, MVT::i32);
}



std::pair<SDOperand, SDOperand> X86TargetLowering::
LowerFrameReturnAddress(bool isFrameAddress, SDOperand Chain, unsigned Depth,
                        SelectionDAG &DAG) {
  SDOperand Result;
  if (Depth)        // Depths > 0 not supported yet!
    Result = DAG.getConstant(0, getPointerTy());
  else {
    SDOperand RetAddrFI = getReturnAddressFrameIndex(DAG);
    if (!isFrameAddress)
      // Just load the return address
      Result = DAG.getLoad(MVT::i32, DAG.getEntryNode(), RetAddrFI,
                           DAG.getSrcValue(NULL));
    else
      Result = DAG.getNode(ISD::SUB, MVT::i32, RetAddrFI,
                           DAG.getConstant(4, MVT::i32));
  }
  return std::make_pair(Result, Chain);
}

/// getCondBrOpcodeForX86CC - Returns the X86 conditional branch opcode
/// which corresponds to the condition code.
static unsigned getCondBrOpcodeForX86CC(unsigned X86CC) {
  switch (X86CC) {
  default: assert(0 && "Unknown X86 conditional code!");
  case X86ISD::COND_A:  return X86::JA;
  case X86ISD::COND_AE: return X86::JAE;
  case X86ISD::COND_B:  return X86::JB;
  case X86ISD::COND_BE: return X86::JBE;
  case X86ISD::COND_E:  return X86::JE;
  case X86ISD::COND_G:  return X86::JG;
  case X86ISD::COND_GE: return X86::JGE;
  case X86ISD::COND_L:  return X86::JL;
  case X86ISD::COND_LE: return X86::JLE;
  case X86ISD::COND_NE: return X86::JNE;
  case X86ISD::COND_NO: return X86::JNO;
  case X86ISD::COND_NP: return X86::JNP;
  case X86ISD::COND_NS: return X86::JNS;
  case X86ISD::COND_O:  return X86::JO;
  case X86ISD::COND_P:  return X86::JP;
  case X86ISD::COND_S:  return X86::JS;
  }
}

/// getX86CC - do a one to one translation of a ISD::CondCode to the X86
/// specific condition code. It returns a X86ISD::COND_INVALID if it cannot
/// do a direct translation.
static unsigned getX86CC(SDOperand CC, bool isFP) {
  ISD::CondCode SetCCOpcode = cast<CondCodeSDNode>(CC)->get();
  unsigned X86CC = X86ISD::COND_INVALID;
  if (!isFP) {
    switch (SetCCOpcode) {
    default: break;
    case ISD::SETEQ:  X86CC = X86ISD::COND_E;  break;
    case ISD::SETGT:  X86CC = X86ISD::COND_G;  break;
    case ISD::SETGE:  X86CC = X86ISD::COND_GE; break;
    case ISD::SETLT:  X86CC = X86ISD::COND_L;  break;
    case ISD::SETLE:  X86CC = X86ISD::COND_LE; break;
    case ISD::SETNE:  X86CC = X86ISD::COND_NE; break;
    case ISD::SETULT: X86CC = X86ISD::COND_B;  break;
    case ISD::SETUGT: X86CC = X86ISD::COND_A;  break;
    case ISD::SETULE: X86CC = X86ISD::COND_BE; break;
    case ISD::SETUGE: X86CC = X86ISD::COND_AE; break;
    }
  } else {
    // On a floating point condition, the flags are set as follows:
    // ZF  PF  CF   op
    //  0 | 0 | 0 | X > Y
    //  0 | 0 | 1 | X < Y
    //  1 | 0 | 0 | X == Y
    //  1 | 1 | 1 | unordered
    switch (SetCCOpcode) {
    default: break;
    case ISD::SETUEQ:
    case ISD::SETEQ: X86CC = X86ISD::COND_E;  break;
    case ISD::SETOGT:
    case ISD::SETGT: X86CC = X86ISD::COND_A;  break;
    case ISD::SETOGE:
    case ISD::SETGE: X86CC = X86ISD::COND_AE; break;
    case ISD::SETULT:
    case ISD::SETLT: X86CC = X86ISD::COND_B;  break;
    case ISD::SETULE:
    case ISD::SETLE: X86CC = X86ISD::COND_BE; break;
    case ISD::SETONE:
    case ISD::SETNE: X86CC = X86ISD::COND_NE; break;
    case ISD::SETUO: X86CC = X86ISD::COND_P;  break;
    case ISD::SETO:  X86CC = X86ISD::COND_NP; break;
    }
  }
  return X86CC;
}

/// hasFPCMov - is there a floating point cmov for the specific X86 condition
/// code. Current x86 isa includes the following FP cmov instructions:
/// fcmovb, fcomvbe, fcomve, fcmovu, fcmovae, fcmova, fcmovne, fcmovnu.
static bool hasFPCMov(unsigned X86CC) {
  switch (X86CC) {
  default:
    return false;
  case X86ISD::COND_B:
  case X86ISD::COND_BE:
  case X86ISD::COND_E:
  case X86ISD::COND_P:
  case X86ISD::COND_A:
  case X86ISD::COND_AE:
  case X86ISD::COND_NE:
  case X86ISD::COND_NP:
    return true;
  }
}

MachineBasicBlock *
X86TargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI,
                                           MachineBasicBlock *BB) {
  switch (MI->getOpcode()) {
  default: assert(false && "Unexpected instr type to insert");
  case X86::CMOV_FR32:
  case X86::CMOV_FR64: {
    // To "insert" a SELECT_CC instruction, we actually have to insert the diamond
    // control-flow pattern.  The incoming instruction knows the destination vreg
    // to set, the condition code register to branch on, the true/false values to
    // select between, and a branch opcode to use.
    const BasicBlock *LLVM_BB = BB->getBasicBlock();
    ilist<MachineBasicBlock>::iterator It = BB;
    ++It;
  
    //  thisMBB:
    //  ...
    //   TrueVal = ...
    //   cmpTY ccX, r1, r2
    //   bCC copy1MBB
    //   fallthrough --> copy0MBB
    MachineBasicBlock *thisMBB = BB;
    MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
    MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB);
    unsigned Opc = getCondBrOpcodeForX86CC(MI->getOperand(3).getImmedValue());
    BuildMI(BB, Opc, 1).addMBB(sinkMBB);
    MachineFunction *F = BB->getParent();
    F->getBasicBlockList().insert(It, copy0MBB);
    F->getBasicBlockList().insert(It, sinkMBB);
    // Update machine-CFG edges
    BB->addSuccessor(copy0MBB);
    BB->addSuccessor(sinkMBB);
  
    //  copy0MBB:
    //   %FalseValue = ...
    //   # fallthrough to sinkMBB
    BB = copy0MBB;
  
    // Update machine-CFG edges
    BB->addSuccessor(sinkMBB);
  
    //  sinkMBB:
    //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
    //  ...
    BB = sinkMBB;
    BuildMI(BB, X86::PHI, 4, MI->getOperand(0).getReg())
      .addReg(MI->getOperand(1).getReg()).addMBB(copy0MBB)
      .addReg(MI->getOperand(2).getReg()).addMBB(thisMBB);

    delete MI;   // The pseudo instruction is gone now.
    return BB;
  }

  case X86::FP_TO_INT16_IN_MEM:
  case X86::FP_TO_INT32_IN_MEM:
  case X86::FP_TO_INT64_IN_MEM: {
    // Change the floating point control register to use "round towards zero"
    // mode when truncating to an integer value.
    MachineFunction *F = BB->getParent();
    int CWFrameIdx = F->getFrameInfo()->CreateStackObject(2, 2);
    addFrameReference(BuildMI(BB, X86::FNSTCW16m, 4), CWFrameIdx);

    // Load the old value of the high byte of the control word...
    unsigned OldCW =
      F->getSSARegMap()->createVirtualRegister(X86::R16RegisterClass);
    addFrameReference(BuildMI(BB, X86::MOV16rm, 4, OldCW), CWFrameIdx);

    // Set the high part to be round to zero...
    addFrameReference(BuildMI(BB, X86::MOV16mi, 5), CWFrameIdx).addImm(0xC7F);

    // Reload the modified control word now...
    addFrameReference(BuildMI(BB, X86::FLDCW16m, 4), CWFrameIdx);

    // Restore the memory image of control word to original value
    addFrameReference(BuildMI(BB, X86::MOV16mr, 5), CWFrameIdx).addReg(OldCW);

    // Get the X86 opcode to use.
    unsigned Opc;
    switch (MI->getOpcode()) {
    case X86::FP_TO_INT16_IN_MEM: Opc = X86::FpIST16m; break;
    case X86::FP_TO_INT32_IN_MEM: Opc = X86::FpIST32m; break;
    case X86::FP_TO_INT64_IN_MEM: Opc = X86::FpIST64m; break;
    }

    X86AddressMode AM;
    MachineOperand &Op = MI->getOperand(0);
    if (Op.isRegister()) {
      AM.BaseType = X86AddressMode::RegBase;
      AM.Base.Reg = Op.getReg();
    } else {
      AM.BaseType = X86AddressMode::FrameIndexBase;
      AM.Base.FrameIndex = Op.getFrameIndex();
    }
    Op = MI->getOperand(1);
    if (Op.isImmediate())
      AM.Scale = Op.getImmedValue();
    Op = MI->getOperand(2);
    if (Op.isImmediate())
      AM.IndexReg = Op.getImmedValue();
    Op = MI->getOperand(3);
    if (Op.isGlobalAddress()) {
      AM.GV = Op.getGlobal();
    } else {
      AM.Disp = Op.getImmedValue();
    }
    addFullAddress(BuildMI(BB, Opc, 5), AM).addReg(MI->getOperand(4).getReg());

    // Reload the original control word now.
    addFrameReference(BuildMI(BB, X86::FLDCW16m, 4), CWFrameIdx);

    delete MI;   // The pseudo instruction is gone now.
    return BB;
  }
  }
}


//===----------------------------------------------------------------------===//
//                           X86 Custom Lowering Hooks
//===----------------------------------------------------------------------===//

/// LowerOperation - Provide custom lowering hooks for some operations.
///
SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
  switch (Op.getOpcode()) {
  default: assert(0 && "Should not custom lower this!");
  case ISD::ADD_PARTS:
  case ISD::SUB_PARTS: {
    assert(Op.getNumOperands() == 4 && Op.getValueType() == MVT::i32 &&
           "Not an i64 add/sub!");
    bool isAdd = Op.getOpcode() == ISD::ADD_PARTS;
    std::vector<MVT::ValueType> Tys;
    Tys.push_back(MVT::i32);
    Tys.push_back(MVT::Flag);
    std::vector<SDOperand> Ops;
    Ops.push_back(Op.getOperand(0));
    Ops.push_back(Op.getOperand(2));
    SDOperand Lo = DAG.getNode(isAdd ? X86ISD::ADD_FLAG : X86ISD::SUB_FLAG,
                               Tys, Ops);
    SDOperand Hi = DAG.getNode(isAdd ? X86ISD::ADC : X86ISD::SBB, MVT::i32,
                               Op.getOperand(1), Op.getOperand(3),
                               Lo.getValue(1));
    Tys.clear();
    Tys.push_back(MVT::i32);
    Tys.push_back(MVT::i32);
    Ops.clear();
    Ops.push_back(Lo);
    Ops.push_back(Hi);
    return DAG.getNode(ISD::MERGE_VALUES, Tys, Ops);
  }
  case ISD::SHL_PARTS:
  case ISD::SRA_PARTS:
  case ISD::SRL_PARTS: {
    assert(Op.getNumOperands() == 3 && Op.getValueType() == MVT::i32 &&
           "Not an i64 shift!");
    bool isSRA = Op.getOpcode() == ISD::SRA_PARTS;
    SDOperand ShOpLo = Op.getOperand(0);
    SDOperand ShOpHi = Op.getOperand(1);
    SDOperand ShAmt  = Op.getOperand(2);
    SDOperand Tmp1 = isSRA ? DAG.getNode(ISD::SRA, MVT::i32, ShOpHi,
                                         DAG.getConstant(31, MVT::i8))
                           : DAG.getConstant(0, MVT::i32);

    SDOperand Tmp2, Tmp3;
    if (Op.getOpcode() == ISD::SHL_PARTS) {
      Tmp2 = DAG.getNode(X86ISD::SHLD, MVT::i32, ShOpHi, ShOpLo, ShAmt);
      Tmp3 = DAG.getNode(ISD::SHL, MVT::i32, ShOpLo, ShAmt);
    } else {
      Tmp2 = DAG.getNode(X86ISD::SHRD, MVT::i32, ShOpLo, ShOpHi, ShAmt);
      Tmp3 = DAG.getNode(isSRA ? ISD::SRA : ISD::SRL, MVT::i32, ShOpHi, ShAmt);
    }

    SDOperand InFlag = DAG.getNode(X86ISD::TEST, MVT::Flag,
                                   ShAmt, DAG.getConstant(32, MVT::i8));

    SDOperand Hi, Lo;
    SDOperand CC = DAG.getConstant(X86ISD::COND_NE, MVT::i8);

    std::vector<MVT::ValueType> Tys;
    Tys.push_back(MVT::i32);
    Tys.push_back(MVT::Flag);
    std::vector<SDOperand> Ops;
    if (Op.getOpcode() == ISD::SHL_PARTS) {
      Ops.push_back(Tmp2);
      Ops.push_back(Tmp3);
      Ops.push_back(CC);
      Ops.push_back(InFlag);
      Hi = DAG.getNode(X86ISD::CMOV, Tys, Ops);
      InFlag = Hi.getValue(1);

      Ops.clear();
      Ops.push_back(Tmp3);
      Ops.push_back(Tmp1);
      Ops.push_back(CC);
      Ops.push_back(InFlag);
      Lo = DAG.getNode(X86ISD::CMOV, Tys, Ops);
    } else {
      Ops.push_back(Tmp2);
      Ops.push_back(Tmp3);
      Ops.push_back(CC);
      Ops.push_back(InFlag);
      Lo = DAG.getNode(X86ISD::CMOV, Tys, Ops);
      InFlag = Lo.getValue(1);

      Ops.clear();
      Ops.push_back(Tmp3);
      Ops.push_back(Tmp1);
      Ops.push_back(CC);
      Ops.push_back(InFlag);
      Hi = DAG.getNode(X86ISD::CMOV, Tys, Ops);
    }

    Tys.clear();
    Tys.push_back(MVT::i32);
    Tys.push_back(MVT::i32);
    Ops.clear();
    Ops.push_back(Lo);
    Ops.push_back(Hi);
    return DAG.getNode(ISD::MERGE_VALUES, Tys, Ops);
  }
  case ISD::SINT_TO_FP: {
    assert(Op.getValueType() == MVT::f64 &&
           Op.getOperand(0).getValueType() <= MVT::i64 &&
           Op.getOperand(0).getValueType() >= MVT::i16 &&
           "Unknown SINT_TO_FP to lower!");

    SDOperand Result;
    MVT::ValueType SrcVT = Op.getOperand(0).getValueType();
    unsigned Size = MVT::getSizeInBits(SrcVT)/8;
    MachineFunction &MF = DAG.getMachineFunction();
    int SSFI = MF.getFrameInfo()->CreateStackObject(Size, Size);
    SDOperand StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
    SDOperand Chain = DAG.getNode(ISD::STORE, MVT::Other,
                                  DAG.getEntryNode(), Op.getOperand(0),
                                  StackSlot, DAG.getSrcValue(NULL));

    // Build the FILD
    std::vector<MVT::ValueType> Tys;
    Tys.push_back(MVT::f64);
    Tys.push_back(MVT::Flag);
    std::vector<SDOperand> Ops;
    Ops.push_back(Chain);
    Ops.push_back(StackSlot);
    Ops.push_back(DAG.getValueType(SrcVT));
    Result = DAG.getNode(X86ISD::FILD, Tys, Ops);
    return Result;
  }
  case ISD::FP_TO_SINT: {
    assert(Op.getValueType() <= MVT::i64 && Op.getValueType() >= MVT::i16 &&
           Op.getOperand(0).getValueType() == MVT::f64 &&
           "Unknown FP_TO_SINT to lower!");
    // We lower FP->sint64 into FISTP64, followed by a load, all to a temporary
    // stack slot.
    MachineFunction &MF = DAG.getMachineFunction();
    unsigned MemSize = MVT::getSizeInBits(Op.getValueType())/8;
    int SSFI = MF.getFrameInfo()->CreateStackObject(MemSize, MemSize);
    SDOperand StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());

    unsigned Opc;
    switch (Op.getValueType()) {
    default: assert(0 && "Invalid FP_TO_SINT to lower!");
    case MVT::i16: Opc = X86ISD::FP_TO_INT16_IN_MEM; break;
    case MVT::i32: Opc = X86ISD::FP_TO_INT32_IN_MEM; break;
    case MVT::i64: Opc = X86ISD::FP_TO_INT64_IN_MEM; break;
    }

    // Build the FP_TO_INT*_IN_MEM
    std::vector<SDOperand> Ops;
    Ops.push_back(DAG.getEntryNode());
    Ops.push_back(Op.getOperand(0));
    Ops.push_back(StackSlot);
    SDOperand FIST = DAG.getNode(Opc, MVT::Other, Ops);

    // Load the result.
    return DAG.getLoad(Op.getValueType(), FIST, StackSlot,
                       DAG.getSrcValue(NULL));
  }
  case ISD::READCYCLECOUNTER: {
    std::vector<MVT::ValueType> Tys;
    Tys.push_back(MVT::Other);
    Tys.push_back(MVT::Flag);
    std::vector<SDOperand> Ops;
    Ops.push_back(Op.getOperand(0));
    SDOperand rd = DAG.getNode(X86ISD::RDTSC_DAG, Tys, Ops);
    Ops.clear();
    Ops.push_back(DAG.getCopyFromReg(rd, X86::EAX, MVT::i32, rd.getValue(1)));
    Ops.push_back(DAG.getCopyFromReg(Ops[0].getValue(1), X86::EDX, 
                                     MVT::i32, Ops[0].getValue(2)));
    Ops.push_back(Ops[1].getValue(1));
    Tys[0] = Tys[1] = MVT::i32;
    Tys.push_back(MVT::Other);
    return DAG.getNode(ISD::MERGE_VALUES, Tys, Ops);
  }
  case ISD::SETCC: {
    assert(Op.getValueType() == MVT::i8 && "SetCC type must be 8-bit integer");
    SDOperand CC   = Op.getOperand(2);
    SDOperand Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
                                 Op.getOperand(0), Op.getOperand(1));
    ISD::CondCode SetCCOpcode = cast<CondCodeSDNode>(CC)->get();
    bool isFP = MVT::isFloatingPoint(Op.getOperand(1).getValueType());
    unsigned X86CC = getX86CC(CC, isFP);
    if (X86CC != X86ISD::COND_INVALID) {
      return DAG.getNode(X86ISD::SETCC, MVT::i8, 
                         DAG.getConstant(X86CC, MVT::i8), Cond);
    } else {
      assert(isFP && "Illegal integer SetCC!");

      std::vector<MVT::ValueType> Tys;
      std::vector<SDOperand> Ops;
      switch (SetCCOpcode) {
      default: assert(false && "Illegal floating point SetCC!");
      case ISD::SETOEQ: {  // !PF & ZF
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_NP, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_E, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::AND, MVT::i8, Tmp1, Tmp2);
      }
      case ISD::SETOLT: {  // !PF & CF
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_NP, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_B, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::AND, MVT::i8, Tmp1, Tmp2);
      }
      case ISD::SETOLE: {  // !PF & (CF || ZF)
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_NP, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_BE, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::AND, MVT::i8, Tmp1, Tmp2);
      }
      case ISD::SETUGT: {  // PF | (!ZF & !CF)
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_P, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_A, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::OR, MVT::i8, Tmp1, Tmp2);
      }
      case ISD::SETUGE: {  // PF | !CF
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_P, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_AE, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::OR, MVT::i8, Tmp1, Tmp2);
      }
      case ISD::SETUNE: {  // PF | !ZF
        Tys.push_back(MVT::i8);
        Tys.push_back(MVT::Flag);
        Ops.push_back(DAG.getConstant(X86ISD::COND_P, MVT::i8));
        Ops.push_back(Cond);
        SDOperand Tmp1 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        SDOperand Tmp2 = DAG.getNode(X86ISD::SETCC, MVT::i8,
                                     DAG.getConstant(X86ISD::COND_NE, MVT::i8),
                                     Tmp1.getValue(1));
        return DAG.getNode(ISD::OR, MVT::i8, Tmp1, Tmp2);
      }
      }
    }
  }
  case ISD::SELECT: {
    MVT::ValueType VT = Op.getValueType();
    bool isFP      = MVT::isFloatingPoint(VT);
    bool isFPStack = isFP && (X86Vector < SSE2);
    bool isFPSSE   = isFP && (X86Vector >= SSE2);
    bool addTest   = false;
    SDOperand Op0 = Op.getOperand(0);
    SDOperand Cond, CC;
    if (Op0.getOpcode() == X86ISD::SETCC) {
      // If condition flag is set by a X86ISD::CMP, then make a copy of it
      // (since flag operand cannot be shared). If the X86ISD::SETCC does not
      // have another use it will be eliminated.
      // If the X86ISD::SETCC has more than one use, then it's probably better
      // to use a test instead of duplicating the X86ISD::CMP (for register
      // pressure reason).
      if (Op0.getOperand(1).getOpcode() == X86ISD::CMP) {
        if (!Op0.hasOneUse()) {
          std::vector<MVT::ValueType> Tys;
          for (unsigned i = 0; i < Op0.Val->getNumValues(); ++i)
            Tys.push_back(Op0.Val->getValueType(i));
          std::vector<SDOperand> Ops;
          for (unsigned i = 0; i < Op0.getNumOperands(); ++i)
            Ops.push_back(Op0.getOperand(i));
          Op0 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        }

        CC   = Op0.getOperand(0);
        Cond = Op0.getOperand(1);
        // Make a copy as flag result cannot be used by more than one.
        Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
                           Cond.getOperand(0), Cond.getOperand(1));
        addTest =
          isFPStack && !hasFPCMov(cast<ConstantSDNode>(CC)->getSignExtended());
      } else
        addTest = true;
    } else if (Op0.getOpcode() == ISD::SETCC) {
      CC = Op0.getOperand(2);
      bool isFP = MVT::isFloatingPoint(Op0.getOperand(1).getValueType());
      unsigned X86CC = getX86CC(CC, isFP);
      CC = DAG.getConstant(X86CC, MVT::i8);
      Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
                         Op0.getOperand(0), Op0.getOperand(1));
    } else
      addTest = true;

    if (addTest) {
      CC = DAG.getConstant(X86ISD::COND_NE, MVT::i8);
      Cond = DAG.getNode(X86ISD::TEST, MVT::Flag, Op0, Op0);
    }

    std::vector<MVT::ValueType> Tys;
    Tys.push_back(Op.getValueType());
    Tys.push_back(MVT::Flag);
    std::vector<SDOperand> Ops;
    // X86ISD::CMOV means set the result (which is operand 1) to the RHS if
    // condition is true.
    Ops.push_back(Op.getOperand(2));
    Ops.push_back(Op.getOperand(1));
    Ops.push_back(CC);
    Ops.push_back(Cond);
    return DAG.getNode(X86ISD::CMOV, Tys, Ops);
  }
  case ISD::BRCOND: {
    bool addTest = false;
    SDOperand Cond  = Op.getOperand(1);
    SDOperand Dest  = Op.getOperand(2);
    SDOperand CC;
    if (Cond.getOpcode() == X86ISD::SETCC) {
      // If condition flag is set by a X86ISD::CMP, then make a copy of it
      // (since flag operand cannot be shared). If the X86ISD::SETCC does not
      // have another use it will be eliminated.
      // If the X86ISD::SETCC has more than one use, then it's probably better
      // to use a test instead of duplicating the X86ISD::CMP (for register
      // pressure reason).
      if (Cond.getOperand(1).getOpcode() == X86ISD::CMP) {
        if (!Cond.hasOneUse()) {
          std::vector<MVT::ValueType> Tys;
          for (unsigned i = 0; i < Cond.Val->getNumValues(); ++i)
            Tys.push_back(Cond.Val->getValueType(i));
          std::vector<SDOperand> Ops;
          for (unsigned i = 0; i < Cond.getNumOperands(); ++i)
            Ops.push_back(Cond.getOperand(i));
          Cond = DAG.getNode(X86ISD::SETCC, Tys, Ops);
        }

        CC   = Cond.getOperand(0);
        Cond = Cond.getOperand(1);
        // Make a copy as flag result cannot be used by more than one.
        Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
                           Cond.getOperand(0), Cond.getOperand(1));
      } else
        addTest = true;
    } else if (Cond.getOpcode() == ISD::SETCC) {
      CC = Cond.getOperand(2);
      bool isFP = MVT::isFloatingPoint(Cond.getOperand(1).getValueType());
      unsigned X86CC = getX86CC(CC, isFP);
      CC = DAG.getConstant(X86CC, MVT::i8);
      Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
                         Cond.getOperand(0), Cond.getOperand(1));
    } else
      addTest = true;

    if (addTest) {
      CC = DAG.getConstant(X86ISD::COND_NE, MVT::i8);
      Cond = DAG.getNode(X86ISD::TEST, MVT::Flag, Cond, Cond);
    }
    return DAG.getNode(X86ISD::BRCOND, Op.getValueType(),
                       Op.getOperand(0), Op.getOperand(2), CC, Cond);
  }
  case ISD::RET: {
    // Can only be return void.
    return DAG.getNode(X86ISD::RET_FLAG, MVT::Other, Op.getOperand(0),
                       DAG.getConstant(getBytesToPopOnReturn(), MVT::i16));
  }
  case ISD::MEMSET: {
    SDOperand InFlag;
    SDOperand Chain = Op.getOperand(0);
    unsigned Align =
      (unsigned)cast<ConstantSDNode>(Op.getOperand(4))->getValue();
    if (Align == 0) Align = 1;

    MVT::ValueType AVT;
    SDOperand Count;
    if (ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Op.getOperand(2))) {
      unsigned ValReg;
      unsigned Val = ValC->getValue() & 255;

      // If the value is a constant, then we can potentially use larger sets.
      switch (Align & 3) {
      case 2:   // WORD aligned
        AVT = MVT::i16;
        if (ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3)))
          Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
        else
          Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
                              DAG.getConstant(1, MVT::i8));
        Val    = (Val << 8) | Val;
        ValReg = X86::AX;
        break;
      case 0:   // DWORD aligned
        AVT = MVT::i32;
        if (ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3)))
          Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
        else
          Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
                              DAG.getConstant(2, MVT::i8));
        Val = (Val << 8)  | Val;
        Val = (Val << 16) | Val;
        ValReg = X86::EAX;
        break;
      default:  // Byte aligned
        AVT = MVT::i8;
        Count = Op.getOperand(3);
        ValReg = X86::AL;
        break;
      }

      Chain  = DAG.getCopyToReg(Chain, ValReg, DAG.getConstant(Val, AVT),
                                InFlag);
      InFlag = Chain.getValue(1);
    } else {
      AVT    = MVT::i8;
      Count  = Op.getOperand(3);
      Chain  = DAG.getCopyToReg(Chain, X86::AL, Op.getOperand(2), InFlag);
      InFlag = Chain.getValue(1);
    }

    Chain  = DAG.getCopyToReg(Chain, X86::ECX, Count, InFlag);
    InFlag = Chain.getValue(1);
    Chain  = DAG.getCopyToReg(Chain, X86::EDI, Op.getOperand(1), InFlag);
    InFlag = Chain.getValue(1);

    return DAG.getNode(X86ISD::REP_STOS, MVT::Other, Chain,
                       DAG.getValueType(AVT), InFlag);
  }
  case ISD::MEMCPY: {
    SDOperand Chain = Op.getOperand(0);
    unsigned Align =
      (unsigned)cast<ConstantSDNode>(Op.getOperand(4))->getValue();
    if (Align == 0) Align = 1;

    MVT::ValueType AVT;
    SDOperand Count;
    switch (Align & 3) {
    case 2:   // WORD aligned
      AVT = MVT::i16;
      if (ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3)))
        Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
      else
        Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
                            DAG.getConstant(1, MVT::i8));
      break;
    case 0:   // DWORD aligned
      AVT = MVT::i32;
      if (ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3)))
        Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
      else
        Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
                            DAG.getConstant(2, MVT::i8));
      break;
    default:  // Byte aligned
      AVT = MVT::i8;
      Count = Op.getOperand(3);
      break;
    }

    SDOperand InFlag;
    Chain  = DAG.getCopyToReg(Chain, X86::ECX, Count, InFlag);
    InFlag = Chain.getValue(1);
    Chain  = DAG.getCopyToReg(Chain, X86::EDI, Op.getOperand(1), InFlag);
    InFlag = Chain.getValue(1);
    Chain  = DAG.getCopyToReg(Chain, X86::ESI, Op.getOperand(2), InFlag);
    InFlag = Chain.getValue(1);

    return DAG.getNode(X86ISD::REP_MOVS, MVT::Other, Chain,
                       DAG.getValueType(AVT), InFlag);
  }
  case ISD::GlobalAddress: {
    SDOperand Result;
    GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
    // For Darwin, external and weak symbols are indirect, so we want to load
    // the value at address GV, not the value of GV itself.  This means that
    // the GlobalAddress must be in the base or index register of the address,
    // not the GV offset field.
    if (getTargetMachine().
        getSubtarget<X86Subtarget>().getIndirectExternAndWeakGlobals() &&
        (GV->hasWeakLinkage() || GV->isExternal()))
      Result = DAG.getLoad(MVT::i32, DAG.getEntryNode(),
                           DAG.getTargetGlobalAddress(GV, getPointerTy()),
                           DAG.getSrcValue(NULL));
    return Result;
  }
  case ISD::VASTART: {
    // vastart just stores the address of the VarArgsFrameIndex slot into the
    // memory location argument.
    // FIXME: Replace MVT::i32 with PointerTy
    SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
    return DAG.getNode(ISD::STORE, MVT::Other, Op.getOperand(0), FR, 
                       Op.getOperand(1), Op.getOperand(2));
  }
  }
}

const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
  switch (Opcode) {
  default: return NULL;
  case X86ISD::ADD_FLAG:           return "X86ISD::ADD_FLAG";
  case X86ISD::SUB_FLAG:           return "X86ISD::SUB_FLAG";
  case X86ISD::ADC:                return "X86ISD::ADC";
  case X86ISD::SBB:                return "X86ISD::SBB";
  case X86ISD::SHLD:               return "X86ISD::SHLD";
  case X86ISD::SHRD:               return "X86ISD::SHRD";
  case X86ISD::FILD:               return "X86ISD::FILD";
  case X86ISD::FP_TO_INT16_IN_MEM: return "X86ISD::FP_TO_INT16_IN_MEM";
  case X86ISD::FP_TO_INT32_IN_MEM: return "X86ISD::FP_TO_INT32_IN_MEM";
  case X86ISD::FP_TO_INT64_IN_MEM: return "X86ISD::FP_TO_INT64_IN_MEM";
  case X86ISD::FLD:                return "X86ISD::FLD";
  case X86ISD::FST:                return "X86ISD::FST";
  case X86ISD::FP_GET_RESULT:      return "X86ISD::FP_GET_RESULT";
  case X86ISD::FP_SET_RESULT:      return "X86ISD::FP_SET_RESULT";
  case X86ISD::CALL:               return "X86ISD::CALL";
  case X86ISD::TAILCALL:           return "X86ISD::TAILCALL";
  case X86ISD::RDTSC_DAG:          return "X86ISD::RDTSC_DAG";
  case X86ISD::CMP:                return "X86ISD::CMP";
  case X86ISD::TEST:               return "X86ISD::TEST";
  case X86ISD::SETCC:              return "X86ISD::SETCC";
  case X86ISD::CMOV:               return "X86ISD::CMOV";
  case X86ISD::BRCOND:             return "X86ISD::BRCOND";
  case X86ISD::RET_FLAG:           return "X86ISD::RET_FLAG";
  case X86ISD::REP_STOS:           return "X86ISD::RET_STOS";
  case X86ISD::REP_MOVS:           return "X86ISD::RET_MOVS";
  }
}

bool X86TargetLowering::isMaskedValueZeroForTargetNode(const SDOperand &Op,
                                                       uint64_t Mask) const {

  unsigned Opc = Op.getOpcode();

  switch (Opc) {
  default:
    assert(Opc >= ISD::BUILTIN_OP_END && "Expected a target specific node");
    break;
  case X86ISD::SETCC: return (Mask & 1) == 0;
  }

  return false;
}