lib/Target/R600/AMDGPUISelLowering.cpp

//===-- AMDGPUISelLowering.cpp - AMDGPU Common DAG lowering functions -----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief This is the parent TargetLowering class for hardware code gen
/// targets.
//
//===----------------------------------------------------------------------===//

#include "AMDGPUISelLowering.h"
#include "AMDGPU.h"
#include "AMDGPURegisterInfo.h"
#include "AMDGPUSubtarget.h"
#include "AMDILIntrinsicInfo.h"
#include "R600MachineFunctionInfo.h"
#include "SIMachineFunctionInfo.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/IR/DataLayout.h"

using namespace llvm;

#include "AMDGPUGenCallingConv.inc"

AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM) :
  TargetLowering(TM, new TargetLoweringObjectFileELF()) {

  // Initialize target lowering borrowed from AMDIL
  InitAMDILLowering();

  // We need to custom lower some of the intrinsics
  setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);

  // Library functions.  These default to Expand, but we have instructions
  // for them.
  setOperationAction(ISD::FCEIL,  MVT::f32, Legal);
  setOperationAction(ISD::FEXP2,  MVT::f32, Legal);
  setOperationAction(ISD::FPOW,   MVT::f32, Legal);
  setOperationAction(ISD::FLOG2,  MVT::f32, Legal);
  setOperationAction(ISD::FABS,   MVT::f32, Legal);
  setOperationAction(ISD::FFLOOR, MVT::f32, Legal);
  setOperationAction(ISD::FRINT,  MVT::f32, Legal);

  // The hardware supports ROTR, but not ROTL
  setOperationAction(ISD::ROTL, MVT::i32, Expand);

  // Lower floating point store/load to integer store/load to reduce the number
  // of patterns in tablegen.
  setOperationAction(ISD::STORE, MVT::f32, Promote);
  AddPromotedToType(ISD::STORE, MVT::f32, MVT::i32);

  setOperationAction(ISD::STORE, MVT::v2f32, Promote);
  AddPromotedToType(ISD::STORE, MVT::v2f32, MVT::v2i32);

  setOperationAction(ISD::STORE, MVT::v4f32, Promote);
  AddPromotedToType(ISD::STORE, MVT::v4f32, MVT::v4i32);

  setOperationAction(ISD::STORE, MVT::f64, Promote);
  AddPromotedToType(ISD::STORE, MVT::f64, MVT::i64);

  // Custom lowering of vector stores is required for local address space
  // stores.
  setOperationAction(ISD::STORE, MVT::v4i32, Custom);
  // XXX: Native v2i32 local address space stores are possible, but not
  // currently implemented.
  setOperationAction(ISD::STORE, MVT::v2i32, Custom);

  setTruncStoreAction(MVT::v2i32, MVT::v2i16, Custom);
  setTruncStoreAction(MVT::v2i32, MVT::v2i8, Custom);
  setTruncStoreAction(MVT::v4i32, MVT::v4i8, Custom);
  // XXX: This can be change to Custom, once ExpandVectorStores can
  // handle 64-bit stores.
  setTruncStoreAction(MVT::v4i32, MVT::v4i16, Expand);

  setOperationAction(ISD::LOAD, MVT::f32, Promote);
  AddPromotedToType(ISD::LOAD, MVT::f32, MVT::i32);

  setOperationAction(ISD::LOAD, MVT::v2f32, Promote);
  AddPromotedToType(ISD::LOAD, MVT::v2f32, MVT::v2i32);

  setOperationAction(ISD::LOAD, MVT::v4f32, Promote);
  AddPromotedToType(ISD::LOAD, MVT::v4f32, MVT::v4i32);

  setOperationAction(ISD::LOAD, MVT::f64, Promote);
  AddPromotedToType(ISD::LOAD, MVT::f64, MVT::i64);

  setOperationAction(ISD::CONCAT_VECTORS, MVT::v4i32, Custom);
  setOperationAction(ISD::CONCAT_VECTORS, MVT::v4f32, Custom);
  setOperationAction(ISD::EXTRACT_SUBVECTOR, MVT::v2i32, Custom);
  setOperationAction(ISD::EXTRACT_SUBVECTOR, MVT::v2f32, Custom);

  setLoadExtAction(ISD::EXTLOAD, MVT::v2i8, Expand);
  setLoadExtAction(ISD::SEXTLOAD, MVT::v2i8, Expand);
  setLoadExtAction(ISD::ZEXTLOAD, MVT::v2i8, Expand);
  setLoadExtAction(ISD::EXTLOAD, MVT::v4i8, Expand);
  setLoadExtAction(ISD::SEXTLOAD, MVT::v4i8, Expand);
  setLoadExtAction(ISD::ZEXTLOAD, MVT::v4i8, Expand);
  setLoadExtAction(ISD::EXTLOAD, MVT::v2i16, Expand);
  setLoadExtAction(ISD::SEXTLOAD, MVT::v2i16, Expand);
  setLoadExtAction(ISD::ZEXTLOAD, MVT::v2i16, Expand);
  setLoadExtAction(ISD::EXTLOAD, MVT::v4i16, Expand);
  setLoadExtAction(ISD::SEXTLOAD, MVT::v4i16, Expand);
  setLoadExtAction(ISD::ZEXTLOAD, MVT::v4i16, Expand);

  setOperationAction(ISD::FNEG, MVT::v2f32, Expand);
  setOperationAction(ISD::FNEG, MVT::v4f32, Expand);

  setOperationAction(ISD::MUL, MVT::i64, Expand);

  setOperationAction(ISD::UDIV, MVT::i32, Expand);
  setOperationAction(ISD::UDIVREM, MVT::i32, Custom);
  setOperationAction(ISD::UREM, MVT::i32, Expand);
  setOperationAction(ISD::VSELECT, MVT::v2f32, Expand);
  setOperationAction(ISD::VSELECT, MVT::v4f32, Expand);

  static const MVT::SimpleValueType IntTypes[] = {
    MVT::v2i32, MVT::v4i32
  };
  const size_t NumIntTypes = array_lengthof(IntTypes);

  for (unsigned int x  = 0; x < NumIntTypes; ++x) {
    MVT::SimpleValueType VT = IntTypes[x];
    //Expand the following operations for the current type by default
    setOperationAction(ISD::ADD,  VT, Expand);
    setOperationAction(ISD::AND,  VT, Expand);
    setOperationAction(ISD::FP_TO_SINT, VT, Expand);
    setOperationAction(ISD::FP_TO_UINT, VT, Expand);
    setOperationAction(ISD::MUL,  VT, Expand);
    setOperationAction(ISD::OR,   VT, Expand);
    setOperationAction(ISD::SHL,  VT, Expand);
    setOperationAction(ISD::SINT_TO_FP, VT, Expand);
    setOperationAction(ISD::SRL,  VT, Expand);
    setOperationAction(ISD::SRA,  VT, Expand);
    setOperationAction(ISD::SUB,  VT, Expand);
    setOperationAction(ISD::UDIV, VT, Expand);
    setOperationAction(ISD::UINT_TO_FP, VT, Expand);
    setOperationAction(ISD::UREM, VT, Expand);
    setOperationAction(ISD::VSELECT, VT, Expand);
    setOperationAction(ISD::XOR,  VT, Expand);
  }

  static const MVT::SimpleValueType FloatTypes[] = {
    MVT::v2f32, MVT::v4f32
  };
  const size_t NumFloatTypes = array_lengthof(FloatTypes);

  for (unsigned int x = 0; x < NumFloatTypes; ++x) {
    MVT::SimpleValueType VT = FloatTypes[x];
    setOperationAction(ISD::FADD, VT, Expand);
    setOperationAction(ISD::FDIV, VT, Expand);
    setOperationAction(ISD::FFLOOR, VT, Expand);
    setOperationAction(ISD::FMUL, VT, Expand);
    setOperationAction(ISD::FRINT, VT, Expand);
    setOperationAction(ISD::FSUB, VT, Expand);
  }
}

//===----------------------------------------------------------------------===//
// Target Information
//===----------------------------------------------------------------------===//

MVT AMDGPUTargetLowering::getVectorIdxTy() const {
  return MVT::i32;
}


//===---------------------------------------------------------------------===//
// Target Properties
//===---------------------------------------------------------------------===//

bool AMDGPUTargetLowering::isFAbsFree(EVT VT) const {
  assert(VT.isFloatingPoint());
  return VT == MVT::f32;
}

bool AMDGPUTargetLowering::isFNegFree(EVT VT) const {
  assert(VT.isFloatingPoint());
  return VT == MVT::f32;
}

//===---------------------------------------------------------------------===//
// TargetLowering Callbacks
//===---------------------------------------------------------------------===//

void AMDGPUTargetLowering::AnalyzeFormalArguments(CCState &State,
                             const SmallVectorImpl<ISD::InputArg> &Ins) const {

  State.AnalyzeFormalArguments(Ins, CC_AMDGPU);
}

SDValue AMDGPUTargetLowering::LowerReturn(
                                     SDValue Chain,
                                     CallingConv::ID CallConv,
                                     bool isVarArg,
                                     const SmallVectorImpl<ISD::OutputArg> &Outs,
                                     const SmallVectorImpl<SDValue> &OutVals,
                                     SDLoc DL, SelectionDAG &DAG) const {
  return DAG.getNode(AMDGPUISD::RET_FLAG, DL, MVT::Other, Chain);
}

//===---------------------------------------------------------------------===//
// Target specific lowering
//===---------------------------------------------------------------------===//

SDValue AMDGPUTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG)
    const {
  switch (Op.getOpcode()) {
  default:
    Op.getNode()->dump();
    assert(0 && "Custom lowering code for this"
        "instruction is not implemented yet!");
    break;
  // AMDIL DAG lowering
  case ISD::SDIV: return LowerSDIV(Op, DAG);
  case ISD::SREM: return LowerSREM(Op, DAG);
  case ISD::SIGN_EXTEND_INREG: return LowerSIGN_EXTEND_INREG(Op, DAG);
  case ISD::BRCOND: return LowerBRCOND(Op, DAG);
  // AMDGPU DAG lowering
  case ISD::CONCAT_VECTORS: return LowerCONCAT_VECTORS(Op, DAG);
  case ISD::EXTRACT_SUBVECTOR: return LowerEXTRACT_SUBVECTOR(Op, DAG);
  case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
  case ISD::STORE: return LowerSTORE(Op, DAG);
  case ISD::UDIVREM: return LowerUDIVREM(Op, DAG);
  }
  return Op;
}

SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
                                                 SDValue Op,
                                                 SelectionDAG &DAG) const {

  const DataLayout *TD = getTargetMachine().getDataLayout();
  GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Op);

  assert(G->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS);
  // XXX: What does the value of G->getOffset() mean?
  assert(G->getOffset() == 0 &&
         "Do not know what to do with an non-zero offset");

  unsigned Offset = MFI->LDSSize;
  const GlobalValue *GV = G->getGlobal();
  uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());

  // XXX: Account for alignment?
  MFI->LDSSize += Size;

  return DAG.getConstant(Offset, getPointerTy(G->getAddressSpace()));
}

void AMDGPUTargetLowering::ExtractVectorElements(SDValue Op, SelectionDAG &DAG,
                                         SmallVectorImpl<SDValue> &Args,
                                         unsigned Start,
                                         unsigned Count) const {
  EVT VT = Op.getValueType();
  for (unsigned i = Start, e = Start + Count; i != e; ++i) {
    Args.push_back(DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SDLoc(Op),
                               VT.getVectorElementType(),
                               Op, DAG.getConstant(i, MVT::i32)));
  }
}

SDValue AMDGPUTargetLowering::LowerCONCAT_VECTORS(SDValue Op,
                                                  SelectionDAG &DAG) const {
  SmallVector<SDValue, 8> Args;
  SDValue A = Op.getOperand(0);
  SDValue B = Op.getOperand(1);

  ExtractVectorElements(A, DAG, Args, 0,
                        A.getValueType().getVectorNumElements());
  ExtractVectorElements(B, DAG, Args, 0,
                        B.getValueType().getVectorNumElements());

  return DAG.getNode(ISD::BUILD_VECTOR, SDLoc(Op), Op.getValueType(),
                     &Args[0], Args.size());
}

SDValue AMDGPUTargetLowering::LowerEXTRACT_SUBVECTOR(SDValue Op,
                                                     SelectionDAG &DAG) const {

  SmallVector<SDValue, 8> Args;
  EVT VT = Op.getValueType();
  unsigned Start = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
  ExtractVectorElements(Op.getOperand(0), DAG, Args, Start,
                        VT.getVectorNumElements());

  return DAG.getNode(ISD::BUILD_VECTOR, SDLoc(Op), Op.getValueType(),
                     &Args[0], Args.size());
}


SDValue AMDGPUTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
    SelectionDAG &DAG) const {
  unsigned IntrinsicID = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
  SDLoc DL(Op);
  EVT VT = Op.getValueType();

  switch (IntrinsicID) {
    default: return Op;
    case AMDGPUIntrinsic::AMDIL_abs:
      return LowerIntrinsicIABS(Op, DAG);
    case AMDGPUIntrinsic::AMDIL_exp:
      return DAG.getNode(ISD::FEXP2, DL, VT, Op.getOperand(1));
    case AMDGPUIntrinsic::AMDGPU_lrp:
      return LowerIntrinsicLRP(Op, DAG);
    case AMDGPUIntrinsic::AMDIL_fraction:
      return DAG.getNode(AMDGPUISD::FRACT, DL, VT, Op.getOperand(1));
    case AMDGPUIntrinsic::AMDIL_max:
      return DAG.getNode(AMDGPUISD::FMAX, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDGPU_imax:
      return DAG.getNode(AMDGPUISD::SMAX, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDGPU_umax:
      return DAG.getNode(AMDGPUISD::UMAX, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDIL_min:
      return DAG.getNode(AMDGPUISD::FMIN, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDGPU_imin:
      return DAG.getNode(AMDGPUISD::SMIN, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDGPU_umin:
      return DAG.getNode(AMDGPUISD::UMIN, DL, VT, Op.getOperand(1),
                                                  Op.getOperand(2));
    case AMDGPUIntrinsic::AMDIL_round_nearest:
      return DAG.getNode(ISD::FRINT, DL, VT, Op.getOperand(1));
  }
}

///IABS(a) = SMAX(sub(0, a), a)
SDValue AMDGPUTargetLowering::LowerIntrinsicIABS(SDValue Op,
    SelectionDAG &DAG) const {

  SDLoc DL(Op);
  EVT VT = Op.getValueType();
  SDValue Neg = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, VT),
                                              Op.getOperand(1));

  return DAG.getNode(AMDGPUISD::SMAX, DL, VT, Neg, Op.getOperand(1));
}

/// Linear Interpolation
/// LRP(a, b, c) = muladd(a,  b, (1 - a) * c)
SDValue AMDGPUTargetLowering::LowerIntrinsicLRP(SDValue Op,
    SelectionDAG &DAG) const {
  SDLoc DL(Op);
  EVT VT = Op.getValueType();
  SDValue OneSubA = DAG.getNode(ISD::FSUB, DL, VT,
                                DAG.getConstantFP(1.0f, MVT::f32),
                                Op.getOperand(1));
  SDValue OneSubAC = DAG.getNode(ISD::FMUL, DL, VT, OneSubA,
                                                    Op.getOperand(3));
  return DAG.getNode(ISD::FADD, DL, VT,
      DAG.getNode(ISD::FMUL, DL, VT, Op.getOperand(1), Op.getOperand(2)),
      OneSubAC);
}

/// \brief Generate Min/Max node
SDValue AMDGPUTargetLowering::LowerMinMax(SDValue Op,
    SelectionDAG &DAG) const {
  SDLoc DL(Op);
  EVT VT = Op.getValueType();

  SDValue LHS = Op.getOperand(0);
  SDValue RHS = Op.getOperand(1);
  SDValue True = Op.getOperand(2);
  SDValue False = Op.getOperand(3);
  SDValue CC = Op.getOperand(4);

  if (VT != MVT::f32 ||
      !((LHS == True && RHS == False) || (LHS == False && RHS == True))) {
    return SDValue();
  }

  ISD::CondCode CCOpcode = cast<CondCodeSDNode>(CC)->get();
  switch (CCOpcode) {
  case ISD::SETOEQ:
  case ISD::SETONE:
  case ISD::SETUNE:
  case ISD::SETNE:
  case ISD::SETUEQ:
  case ISD::SETEQ:
  case ISD::SETFALSE:
  case ISD::SETFALSE2:
  case ISD::SETTRUE:
  case ISD::SETTRUE2:
  case ISD::SETUO:
  case ISD::SETO:
    assert(0 && "Operation should already be optimised !");
  case ISD::SETULE:
  case ISD::SETULT:
  case ISD::SETOLE:
  case ISD::SETOLT:
  case ISD::SETLE:
  case ISD::SETLT: {
    if (LHS == True)
      return DAG.getNode(AMDGPUISD::FMIN, DL, VT, LHS, RHS);
    else
      return DAG.getNode(AMDGPUISD::FMAX, DL, VT, LHS, RHS);
  }
  case ISD::SETGT:
  case ISD::SETGE:
  case ISD::SETUGE:
  case ISD::SETOGE:
  case ISD::SETUGT:
  case ISD::SETOGT: {
    if (LHS == True)
      return DAG.getNode(AMDGPUISD::FMAX, DL, VT, LHS, RHS);
    else
      return DAG.getNode(AMDGPUISD::FMIN, DL, VT, LHS, RHS);
  }
  case ISD::SETCC_INVALID:
    assert(0 && "Invalid setcc condcode !");
  }
  return Op;
}

SDValue AMDGPUTargetLowering::MergeVectorStore(const SDValue &Op,
                                               SelectionDAG &DAG) const {
  StoreSDNode *Store = dyn_cast<StoreSDNode>(Op);
  EVT MemVT = Store->getMemoryVT();
  unsigned MemBits = MemVT.getSizeInBits();

  // Byte stores are really expensive, so if possible, try to pack
  // 32-bit vector truncatating store into an i32 store.
  // XXX: We could also handle optimize other vector bitwidths
  if (!MemVT.isVector() || MemBits > 32) {
    return SDValue();
  }

  SDLoc DL(Op);
  const SDValue &Value = Store->getValue();
  EVT VT = Value.getValueType();
  const SDValue &Ptr = Store->getBasePtr();
  EVT MemEltVT = MemVT.getVectorElementType();
  unsigned MemEltBits = MemEltVT.getSizeInBits();
  unsigned MemNumElements = MemVT.getVectorNumElements();
  EVT PackedVT = EVT::getIntegerVT(*DAG.getContext(), MemVT.getSizeInBits());
  SDValue Mask;
  switch(MemEltBits) {
  case 8:
    Mask = DAG.getConstant(0xFF, PackedVT);
    break;
  case 16:
    Mask = DAG.getConstant(0xFFFF, PackedVT);
    break;
  default:
    llvm_unreachable("Cannot lower this vector store");
  }
  SDValue PackedValue;
  for (unsigned i = 0; i < MemNumElements; ++i) {
    EVT ElemVT = VT.getVectorElementType();
    SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, ElemVT, Value,
                              DAG.getConstant(i, MVT::i32));
    Elt = DAG.getZExtOrTrunc(Elt, DL, PackedVT);
    Elt = DAG.getNode(ISD::AND, DL, PackedVT, Elt, Mask);
    SDValue Shift = DAG.getConstant(MemEltBits * i, PackedVT);
    Elt = DAG.getNode(ISD::SHL, DL, PackedVT, Elt, Shift);
    if (i == 0) {
      PackedValue = Elt;
    } else {
      PackedValue = DAG.getNode(ISD::OR, DL, PackedVT, PackedValue, Elt);
    }
  }
  return DAG.getStore(Store->getChain(), DL, PackedValue, Ptr,
                      MachinePointerInfo(Store->getMemOperand()->getValue()),
                      Store->isVolatile(),  Store->isNonTemporal(),
                      Store->getAlignment());
}

SDValue AMDGPUTargetLowering::SplitVectorStore(SDValue Op,
                                            SelectionDAG &DAG) const {
  StoreSDNode *Store = cast<StoreSDNode>(Op);
  EVT MemEltVT = Store->getMemoryVT().getVectorElementType();
  EVT EltVT = Store->getValue().getValueType().getVectorElementType();
  EVT PtrVT = Store->getBasePtr().getValueType();
  unsigned NumElts = Store->getMemoryVT().getVectorNumElements();
  SDLoc SL(Op);

  SmallVector<SDValue, 8> Chains;

  for (unsigned i = 0, e = NumElts; i != e; ++i) {
    SDValue Val = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, EltVT,
                              Store->getValue(), DAG.getConstant(i, MVT::i32));
    SDValue Ptr = DAG.getNode(ISD::ADD, SL, PtrVT,
                              Store->getBasePtr(),
                            DAG.getConstant(i * (MemEltVT.getSizeInBits() / 8),
                                            PtrVT));
    Chains.push_back(DAG.getTruncStore(Store->getChain(), SL, Val, Ptr,
                         MachinePointerInfo(Store->getMemOperand()->getValue()),
                         MemEltVT, Store->isVolatile(), Store->isNonTemporal(),
                         Store->getAlignment()));
  }
  return DAG.getNode(ISD::TokenFactor, SL, MVT::Other, &Chains[0], NumElts);
}

SDValue AMDGPUTargetLowering::LowerSTORE(SDValue Op, SelectionDAG &DAG) const {
  SDValue Result = AMDGPUTargetLowering::MergeVectorStore(Op, DAG);
  if (Result.getNode()) {
    return Result;
  }

  StoreSDNode *Store = cast<StoreSDNode>(Op);
  if (Store->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS &&
      Store->getValue().getValueType().isVector()) {
    return SplitVectorStore(Op, DAG);
  }
  return SDValue();
}

SDValue AMDGPUTargetLowering::LowerUDIVREM(SDValue Op,
    SelectionDAG &DAG) const {
  SDLoc DL(Op);
  EVT VT = Op.getValueType();

  SDValue Num = Op.getOperand(0);
  SDValue Den = Op.getOperand(1);

  SmallVector<SDValue, 8> Results;

  // RCP =  URECIP(Den) = 2^32 / Den + e
  // e is rounding error.
  SDValue RCP = DAG.getNode(AMDGPUISD::URECIP, DL, VT, Den);

  // RCP_LO = umulo(RCP, Den) */
  SDValue RCP_LO = DAG.getNode(ISD::UMULO, DL, VT, RCP, Den);

  // RCP_HI = mulhu (RCP, Den) */
  SDValue RCP_HI = DAG.getNode(ISD::MULHU, DL, VT, RCP, Den);

  // NEG_RCP_LO = -RCP_LO
  SDValue NEG_RCP_LO = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, VT),
                                                     RCP_LO);

  // ABS_RCP_LO = (RCP_HI == 0 ? NEG_RCP_LO : RCP_LO)
  SDValue ABS_RCP_LO = DAG.getSelectCC(DL, RCP_HI, DAG.getConstant(0, VT),
                                           NEG_RCP_LO, RCP_LO,
                                           ISD::SETEQ);
  // Calculate the rounding error from the URECIP instruction
  // E = mulhu(ABS_RCP_LO, RCP)
  SDValue E = DAG.getNode(ISD::MULHU, DL, VT, ABS_RCP_LO, RCP);

  // RCP_A_E = RCP + E
  SDValue RCP_A_E = DAG.getNode(ISD::ADD, DL, VT, RCP, E);

  // RCP_S_E = RCP - E
  SDValue RCP_S_E = DAG.getNode(ISD::SUB, DL, VT, RCP, E);

  // Tmp0 = (RCP_HI == 0 ? RCP_A_E : RCP_SUB_E)
  SDValue Tmp0 = DAG.getSelectCC(DL, RCP_HI, DAG.getConstant(0, VT),
                                     RCP_A_E, RCP_S_E,
                                     ISD::SETEQ);
  // Quotient = mulhu(Tmp0, Num)
  SDValue Quotient = DAG.getNode(ISD::MULHU, DL, VT, Tmp0, Num);

  // Num_S_Remainder = Quotient * Den
  SDValue Num_S_Remainder = DAG.getNode(ISD::UMULO, DL, VT, Quotient, Den);

  // Remainder = Num - Num_S_Remainder
  SDValue Remainder = DAG.getNode(ISD::SUB, DL, VT, Num, Num_S_Remainder);

  // Remainder_GE_Den = (Remainder >= Den ? -1 : 0)
  SDValue Remainder_GE_Den = DAG.getSelectCC(DL, Remainder, Den,
                                                 DAG.getConstant(-1, VT),
                                                 DAG.getConstant(0, VT),
                                                 ISD::SETGE);
  // Remainder_GE_Zero = (Remainder >= 0 ? -1 : 0)
  SDValue Remainder_GE_Zero = DAG.getSelectCC(DL, Remainder,
                                                  DAG.getConstant(0, VT),
                                                  DAG.getConstant(-1, VT),
                                                  DAG.getConstant(0, VT),
                                                  ISD::SETGE);
  // Tmp1 = Remainder_GE_Den & Remainder_GE_Zero
  SDValue Tmp1 = DAG.getNode(ISD::AND, DL, VT, Remainder_GE_Den,
                                               Remainder_GE_Zero);

  // Calculate Division result:

  // Quotient_A_One = Quotient + 1
  SDValue Quotient_A_One = DAG.getNode(ISD::ADD, DL, VT, Quotient,
                                                         DAG.getConstant(1, VT));

  // Quotient_S_One = Quotient - 1
  SDValue Quotient_S_One = DAG.getNode(ISD::SUB, DL, VT, Quotient,
                                                         DAG.getConstant(1, VT));

  // Div = (Tmp1 == 0 ? Quotient : Quotient_A_One)
  SDValue Div = DAG.getSelectCC(DL, Tmp1, DAG.getConstant(0, VT),
                                     Quotient, Quotient_A_One, ISD::SETEQ);

  // Div = (Remainder_GE_Zero == 0 ? Quotient_S_One : Div)
  Div = DAG.getSelectCC(DL, Remainder_GE_Zero, DAG.getConstant(0, VT),
                            Quotient_S_One, Div, ISD::SETEQ);

  // Calculate Rem result:

  // Remainder_S_Den = Remainder - Den
  SDValue Remainder_S_Den = DAG.getNode(ISD::SUB, DL, VT, Remainder, Den);

  // Remainder_A_Den = Remainder + Den
  SDValue Remainder_A_Den = DAG.getNode(ISD::ADD, DL, VT, Remainder, Den);

  // Rem = (Tmp1 == 0 ? Remainder : Remainder_S_Den)
  SDValue Rem = DAG.getSelectCC(DL, Tmp1, DAG.getConstant(0, VT),
                                    Remainder, Remainder_S_Den, ISD::SETEQ);

  // Rem = (Remainder_GE_Zero == 0 ? Remainder_A_Den : Rem)
  Rem = DAG.getSelectCC(DL, Remainder_GE_Zero, DAG.getConstant(0, VT),
                            Remainder_A_Den, Rem, ISD::SETEQ);
  SDValue Ops[2];
  Ops[0] = Div;
  Ops[1] = Rem;
  return DAG.getMergeValues(Ops, 2, DL);
}


//===----------------------------------------------------------------------===//
// Helper functions
//===----------------------------------------------------------------------===//

bool AMDGPUTargetLowering::isHWTrueValue(SDValue Op) const {
  if (ConstantFPSDNode * CFP = dyn_cast<ConstantFPSDNode>(Op)) {
    return CFP->isExactlyValue(1.0);
  }
  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
    return C->isAllOnesValue();
  }
  return false;
}

bool AMDGPUTargetLowering::isHWFalseValue(SDValue Op) const {
  if (ConstantFPSDNode * CFP = dyn_cast<ConstantFPSDNode>(Op)) {
    return CFP->getValueAPF().isZero();
  }
  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
    return C->isNullValue();
  }
  return false;
}

SDValue AMDGPUTargetLowering::CreateLiveInRegister(SelectionDAG &DAG,
                                                  const TargetRegisterClass *RC,
                                                   unsigned Reg, EVT VT) const {
  MachineFunction &MF = DAG.getMachineFunction();
  MachineRegisterInfo &MRI = MF.getRegInfo();
  unsigned VirtualRegister;
  if (!MRI.isLiveIn(Reg)) {
    VirtualRegister = MRI.createVirtualRegister(RC);
    MRI.addLiveIn(Reg, VirtualRegister);
  } else {
    VirtualRegister = MRI.getLiveInVirtReg(Reg);
  }
  return DAG.getRegister(VirtualRegister, VT);
}

#define NODE_NAME_CASE(node) case AMDGPUISD::node: return #node;

const char* AMDGPUTargetLowering::getTargetNodeName(unsigned Opcode) const {
  switch (Opcode) {
  default: return 0;
  // AMDIL DAG nodes
  NODE_NAME_CASE(CALL);
  NODE_NAME_CASE(UMUL);
  NODE_NAME_CASE(DIV_INF);
  NODE_NAME_CASE(RET_FLAG);
  NODE_NAME_CASE(BRANCH_COND);

  // AMDGPU DAG nodes
  NODE_NAME_CASE(DWORDADDR)
  NODE_NAME_CASE(FRACT)
  NODE_NAME_CASE(FMAX)
  NODE_NAME_CASE(SMAX)
  NODE_NAME_CASE(UMAX)
  NODE_NAME_CASE(FMIN)
  NODE_NAME_CASE(SMIN)
  NODE_NAME_CASE(UMIN)
  NODE_NAME_CASE(URECIP)
  NODE_NAME_CASE(EXPORT)
  NODE_NAME_CASE(CONST_ADDRESS)
  NODE_NAME_CASE(REGISTER_LOAD)
  NODE_NAME_CASE(REGISTER_STORE)
  NODE_NAME_CASE(LOAD_CONSTANT)
  NODE_NAME_CASE(LOAD_INPUT)
  NODE_NAME_CASE(SAMPLE)
  NODE_NAME_CASE(SAMPLEB)
  NODE_NAME_CASE(SAMPLED)
  NODE_NAME_CASE(SAMPLEL)
  NODE_NAME_CASE(STORE_MSKOR)
  }
}