lib/Target/X86/X86ISelLowering.cpp

//===-- X86ISelLowering.cpp - X86 DAG Lowering Implementation -------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that X86 uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86InstrBuilder.h"
#include "X86ISelLowering.h"
#include "X86TargetMachine.h"
#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalAlias.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/VectorExtras.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

static cl::opt<bool>
DisableMMX("disable-mmx", cl::Hidden, cl::desc("Disable use of MMX"));

// Forward declarations.
static SDValue getMOVL(SelectionDAG &DAG, DebugLoc dl, MVT VT, SDValue V1,
                       SDValue V2);

static TargetLoweringObjectFile *createTLOF(X86TargetMachine &TM) {
  switch (TM.getSubtarget<X86Subtarget>().TargetType) {
  default: llvm_unreachable("unknown subtarget type");
  case X86Subtarget::isDarwin:
    return new TargetLoweringObjectFileMachO();
  case X86Subtarget::isELF:
    return new TargetLoweringObjectFileELF();
  case X86Subtarget::isMingw:
  case X86Subtarget::isCygwin:
  case X86Subtarget::isWindows:
    return new TargetLoweringObjectFileCOFF();
  }
  
}

X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
  : TargetLowering(TM, createTLOF(TM)) {
  Subtarget = &TM.getSubtarget<X86Subtarget>();
  X86ScalarSSEf64 = Subtarget->hasSSE2();
  X86ScalarSSEf32 = Subtarget->hasSSE1();
  X86StackPtr = Subtarget->is64Bit() ? X86::RSP : X86::ESP;

  RegInfo = TM.getRegisterInfo();
  TD = getTargetData();

  // Set up the TargetLowering object.

  // X86 is weird, it always uses i8 for shift amounts and setcc results.
  setShiftAmountType(MVT::i8);
  setBooleanContents(ZeroOrOneBooleanContent);
  setSchedulingPreference(SchedulingForRegPressure);
  setStackPointerRegisterToSaveRestore(X86StackPtr);

  if (Subtarget->isTargetDarwin()) {
    // Darwin should use _setjmp/_longjmp instead of setjmp/longjmp.
    setUseUnderscoreSetJmp(false);
    setUseUnderscoreLongJmp(false);
  } else if (Subtarget->isTargetMingw()) {
    // MS runtime is weird: it exports _setjmp, but longjmp!
    setUseUnderscoreSetJmp(true);
    setUseUnderscoreLongJmp(false);
  } else {
    setUseUnderscoreSetJmp(true);
    setUseUnderscoreLongJmp(true);
  }

  // Set up the register classes.
  addRegisterClass(MVT::i8, X86::GR8RegisterClass);
  addRegisterClass(MVT::i16, X86::GR16RegisterClass);
  addRegisterClass(MVT::i32, X86::GR32RegisterClass);
  if (Subtarget->is64Bit())
    addRegisterClass(MVT::i64, X86::GR64RegisterClass);

  setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);

  // We don't accept any truncstore of integer registers.
  setTruncStoreAction(MVT::i64, MVT::i32, Expand);
  setTruncStoreAction(MVT::i64, MVT::i16, Expand);
  setTruncStoreAction(MVT::i64, MVT::i8 , Expand);
  setTruncStoreAction(MVT::i32, MVT::i16, Expand);
  setTruncStoreAction(MVT::i32, MVT::i8 , Expand);
  setTruncStoreAction(MVT::i16, MVT::i8,  Expand);

  // SETOEQ and SETUNE require checking two conditions.
  setCondCodeAction(ISD::SETOEQ, MVT::f32, Expand);
  setCondCodeAction(ISD::SETOEQ, MVT::f64, Expand);
  setCondCodeAction(ISD::SETOEQ, MVT::f80, Expand);
  setCondCodeAction(ISD::SETUNE, MVT::f32, Expand);
  setCondCodeAction(ISD::SETUNE, MVT::f64, Expand);
  setCondCodeAction(ISD::SETUNE, MVT::f80, Expand);

  // Promote all UINT_TO_FP to larger SINT_TO_FP's, as X86 doesn't have this
  // operation.
  setOperationAction(ISD::UINT_TO_FP       , MVT::i1   , Promote);
  setOperationAction(ISD::UINT_TO_FP       , MVT::i8   , Promote);
  setOperationAction(ISD::UINT_TO_FP       , MVT::i16  , Promote);

  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::UINT_TO_FP     , MVT::i32  , Promote);
    setOperationAction(ISD::UINT_TO_FP     , MVT::i64  , Expand);
  } else if (!UseSoftFloat) {
    if (X86ScalarSSEf64) {
      // We have an impenetrably clever algorithm for ui64->double only.
      setOperationAction(ISD::UINT_TO_FP   , MVT::i64  , Custom);
    }
    // We have an algorithm for SSE2, and we turn this into a 64-bit
    // FILD for other targets.
    setOperationAction(ISD::UINT_TO_FP   , MVT::i32  , Custom);
  }

  // Promote i1/i8 SINT_TO_FP to larger SINT_TO_FP's, as X86 doesn't have
  // this operation.
  setOperationAction(ISD::SINT_TO_FP       , MVT::i1   , Promote);
  setOperationAction(ISD::SINT_TO_FP       , MVT::i8   , Promote);

  if (!UseSoftFloat) {
    // SSE has no i16 to fp conversion, only i32
    if (X86ScalarSSEf32) {
      setOperationAction(ISD::SINT_TO_FP     , MVT::i16  , Promote);
      // f32 and f64 cases are Legal, f80 case is not
      setOperationAction(ISD::SINT_TO_FP     , MVT::i32  , Custom);
    } else {
      setOperationAction(ISD::SINT_TO_FP     , MVT::i16  , Custom);
      setOperationAction(ISD::SINT_TO_FP     , MVT::i32  , Custom);
    }
  } else {
    setOperationAction(ISD::SINT_TO_FP     , MVT::i16  , Promote);
    setOperationAction(ISD::SINT_TO_FP     , MVT::i32  , Promote);
  }

  // In 32-bit mode these are custom lowered.  In 64-bit mode F32 and F64
  // are Legal, f80 is custom lowered.
  setOperationAction(ISD::FP_TO_SINT     , MVT::i64  , Custom);
  setOperationAction(ISD::SINT_TO_FP     , MVT::i64  , Custom);

  // Promote i1/i8 FP_TO_SINT to larger FP_TO_SINTS's, as X86 doesn't have
  // this operation.
  setOperationAction(ISD::FP_TO_SINT       , MVT::i1   , Promote);
  setOperationAction(ISD::FP_TO_SINT       , MVT::i8   , Promote);

  if (X86ScalarSSEf32) {
    setOperationAction(ISD::FP_TO_SINT     , MVT::i16  , Promote);
    // f32 and f64 cases are Legal, f80 case is not
    setOperationAction(ISD::FP_TO_SINT     , MVT::i32  , Custom);
  } else {
    setOperationAction(ISD::FP_TO_SINT     , MVT::i16  , Custom);
    setOperationAction(ISD::FP_TO_SINT     , MVT::i32  , Custom);
  }

  // Handle FP_TO_UINT by promoting the destination to a larger signed
  // conversion.
  setOperationAction(ISD::FP_TO_UINT       , MVT::i1   , Promote);
  setOperationAction(ISD::FP_TO_UINT       , MVT::i8   , Promote);
  setOperationAction(ISD::FP_TO_UINT       , MVT::i16  , Promote);

  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::FP_TO_UINT     , MVT::i64  , Expand);
    setOperationAction(ISD::FP_TO_UINT     , MVT::i32  , Promote);
  } else if (!UseSoftFloat) {
    if (X86ScalarSSEf32 && !Subtarget->hasSSE3())
      // Expand FP_TO_UINT into a select.
      // FIXME: We would like to use a Custom expander here eventually to do
      // the optimal thing for SSE vs. the default expansion in the legalizer.
      setOperationAction(ISD::FP_TO_UINT   , MVT::i32  , Expand);
    else
      // With SSE3 we can use fisttpll to convert to a signed i64; without
      // SSE, we're stuck with a fistpll.
      setOperationAction(ISD::FP_TO_UINT   , MVT::i32  , Custom);
  }

  // TODO: when we have SSE, these could be more efficient, by using movd/movq.
  if (!X86ScalarSSEf64) {
    setOperationAction(ISD::BIT_CONVERT      , MVT::f32  , Expand);
    setOperationAction(ISD::BIT_CONVERT      , MVT::i32  , Expand);
  }

  // Scalar integer divide and remainder are lowered to use operations that
  // produce two results, to match the available instructions. This exposes
  // the two-result form to trivial CSE, which is able to combine x/y and x%y
  // into a single instruction.
  //
  // Scalar integer multiply-high is also lowered to use two-result
  // operations, to match the available instructions. However, plain multiply
  // (low) operations are left as Legal, as there are single-result
  // instructions for this in x86. Using the two-result multiply instructions
  // when both high and low results are needed must be arranged by dagcombine.
  setOperationAction(ISD::MULHS           , MVT::i8    , Expand);
  setOperationAction(ISD::MULHU           , MVT::i8    , Expand);
  setOperationAction(ISD::SDIV            , MVT::i8    , Expand);
  setOperationAction(ISD::UDIV            , MVT::i8    , Expand);
  setOperationAction(ISD::SREM            , MVT::i8    , Expand);
  setOperationAction(ISD::UREM            , MVT::i8    , Expand);
  setOperationAction(ISD::MULHS           , MVT::i16   , Expand);
  setOperationAction(ISD::MULHU           , MVT::i16   , Expand);
  setOperationAction(ISD::SDIV            , MVT::i16   , Expand);
  setOperationAction(ISD::UDIV            , MVT::i16   , Expand);
  setOperationAction(ISD::SREM            , MVT::i16   , Expand);
  setOperationAction(ISD::UREM            , MVT::i16   , Expand);
  setOperationAction(ISD::MULHS           , MVT::i32   , Expand);
  setOperationAction(ISD::MULHU           , MVT::i32   , Expand);
  setOperationAction(ISD::SDIV            , MVT::i32   , Expand);
  setOperationAction(ISD::UDIV            , MVT::i32   , Expand);
  setOperationAction(ISD::SREM            , MVT::i32   , Expand);
  setOperationAction(ISD::UREM            , MVT::i32   , Expand);
  setOperationAction(ISD::MULHS           , MVT::i64   , Expand);
  setOperationAction(ISD::MULHU           , MVT::i64   , Expand);
  setOperationAction(ISD::SDIV            , MVT::i64   , Expand);
  setOperationAction(ISD::UDIV            , MVT::i64   , Expand);
  setOperationAction(ISD::SREM            , MVT::i64   , Expand);
  setOperationAction(ISD::UREM            , MVT::i64   , Expand);

  setOperationAction(ISD::BR_JT            , MVT::Other, Expand);
  setOperationAction(ISD::BRCOND           , MVT::Other, Custom);
  setOperationAction(ISD::BR_CC            , MVT::Other, Expand);
  setOperationAction(ISD::SELECT_CC        , MVT::Other, Expand);
  if (Subtarget->is64Bit())
    setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i32, Legal);
  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16  , Legal);
  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8   , Legal);
  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1   , Expand);
  setOperationAction(ISD::FP_ROUND_INREG   , MVT::f32  , Expand);
  setOperationAction(ISD::FREM             , MVT::f32  , Expand);
  setOperationAction(ISD::FREM             , MVT::f64  , Expand);
  setOperationAction(ISD::FREM             , MVT::f80  , Expand);
  setOperationAction(ISD::FLT_ROUNDS_      , MVT::i32  , Custom);

  setOperationAction(ISD::CTPOP            , MVT::i8   , Expand);
  setOperationAction(ISD::CTTZ             , MVT::i8   , Custom);
  setOperationAction(ISD::CTLZ             , MVT::i8   , Custom);
  setOperationAction(ISD::CTPOP            , MVT::i16  , Expand);
  setOperationAction(ISD::CTTZ             , MVT::i16  , Custom);
  setOperationAction(ISD::CTLZ             , MVT::i16  , Custom);
  setOperationAction(ISD::CTPOP            , MVT::i32  , Expand);
  setOperationAction(ISD::CTTZ             , MVT::i32  , Custom);
  setOperationAction(ISD::CTLZ             , MVT::i32  , Custom);
  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::CTPOP          , MVT::i64  , Expand);
    setOperationAction(ISD::CTTZ           , MVT::i64  , Custom);
    setOperationAction(ISD::CTLZ           , MVT::i64  , Custom);
  }

  setOperationAction(ISD::READCYCLECOUNTER , MVT::i64  , Custom);
  setOperationAction(ISD::BSWAP            , MVT::i16  , Expand);

  // These should be promoted to a larger select which is supported.
  setOperationAction(ISD::SELECT           , MVT::i1   , Promote);
  setOperationAction(ISD::SELECT           , MVT::i8   , Promote);
  // X86 wants to expand cmov itself.
  setOperationAction(ISD::SELECT          , MVT::i16  , Custom);
  setOperationAction(ISD::SELECT          , MVT::i32  , Custom);
  setOperationAction(ISD::SELECT          , MVT::f32  , Custom);
  setOperationAction(ISD::SELECT          , MVT::f64  , Custom);
  setOperationAction(ISD::SELECT          , MVT::f80  , Custom);
  setOperationAction(ISD::SETCC           , MVT::i8   , Custom);
  setOperationAction(ISD::SETCC           , MVT::i16  , Custom);
  setOperationAction(ISD::SETCC           , MVT::i32  , Custom);
  setOperationAction(ISD::SETCC           , MVT::f32  , Custom);
  setOperationAction(ISD::SETCC           , MVT::f64  , Custom);
  setOperationAction(ISD::SETCC           , MVT::f80  , Custom);
  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::SELECT        , MVT::i64  , Custom);
    setOperationAction(ISD::SETCC         , MVT::i64  , Custom);
  }
  // X86 ret instruction may pop stack.
  setOperationAction(ISD::RET             , MVT::Other, Custom);
  setOperationAction(ISD::EH_RETURN       , MVT::Other, Custom);

  // Darwin ABI issue.
  setOperationAction(ISD::ConstantPool    , MVT::i32  , Custom);
  setOperationAction(ISD::JumpTable       , MVT::i32  , Custom);
  setOperationAction(ISD::GlobalAddress   , MVT::i32  , Custom);
  setOperationAction(ISD::GlobalTLSAddress, MVT::i32  , Custom);
  if (Subtarget->is64Bit())
    setOperationAction(ISD::GlobalTLSAddress, MVT::i64, Custom);
  setOperationAction(ISD::ExternalSymbol  , MVT::i32  , Custom);
  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::ConstantPool  , MVT::i64  , Custom);
    setOperationAction(ISD::JumpTable     , MVT::i64  , Custom);
    setOperationAction(ISD::GlobalAddress , MVT::i64  , Custom);
    setOperationAction(ISD::ExternalSymbol, MVT::i64  , Custom);
  }
  // 64-bit addm sub, shl, sra, srl (iff 32-bit x86)
  setOperationAction(ISD::SHL_PARTS       , MVT::i32  , Custom);
  setOperationAction(ISD::SRA_PARTS       , MVT::i32  , Custom);
  setOperationAction(ISD::SRL_PARTS       , MVT::i32  , Custom);
  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::SHL_PARTS     , MVT::i64  , Custom);
    setOperationAction(ISD::SRA_PARTS     , MVT::i64  , Custom);
    setOperationAction(ISD::SRL_PARTS     , MVT::i64  , Custom);
  }

  if (Subtarget->hasSSE1())
    setOperationAction(ISD::PREFETCH      , MVT::Other, Legal);

  if (!Subtarget->hasSSE2())
    setOperationAction(ISD::MEMBARRIER    , MVT::Other, Expand);

  // Expand certain atomics
  setOperationAction(ISD::ATOMIC_CMP_SWAP, MVT::i8, Custom);
  setOperationAction(ISD::ATOMIC_CMP_SWAP, MVT::i16, Custom);
  setOperationAction(ISD::ATOMIC_CMP_SWAP, MVT::i32, Custom);
  setOperationAction(ISD::ATOMIC_CMP_SWAP, MVT::i64, Custom);

  setOperationAction(ISD::ATOMIC_LOAD_SUB, MVT::i8, Custom);
  setOperationAction(ISD::ATOMIC_LOAD_SUB, MVT::i16, Custom);
  setOperationAction(ISD::ATOMIC_LOAD_SUB, MVT::i32, Custom);
  setOperationAction(ISD::ATOMIC_LOAD_SUB, MVT::i64, Custom);

  if (!Subtarget->is64Bit()) {
    setOperationAction(ISD::ATOMIC_LOAD_ADD, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_LOAD_SUB, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_LOAD_AND, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_LOAD_OR, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_LOAD_XOR, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_LOAD_NAND, MVT::i64, Custom);
    setOperationAction(ISD::ATOMIC_SWAP, MVT::i64, Custom);
  }

  // Use the default ISD::DBG_STOPPOINT, ISD::DECLARE expansion.
  setOperationAction(ISD::DBG_STOPPOINT, MVT::Other, Expand);
  // FIXME - use subtarget debug flags
  if (!Subtarget->isTargetDarwin() &&
      !Subtarget->isTargetELF() &&
      !Subtarget->isTargetCygMing()) {
    setOperationAction(ISD::DBG_LABEL, MVT::Other, Expand);
    setOperationAction(ISD::EH_LABEL, MVT::Other, Expand);
  }

  setOperationAction(ISD::EXCEPTIONADDR, MVT::i64, Expand);
  setOperationAction(ISD::EHSELECTION,   MVT::i64, Expand);
  setOperationAction(ISD::EXCEPTIONADDR, MVT::i32, Expand);
  setOperationAction(ISD::EHSELECTION,   MVT::i32, Expand);
  if (Subtarget->is64Bit()) {
    setExceptionPointerRegister(X86::RAX);
    setExceptionSelectorRegister(X86::RDX);
  } else {
    setExceptionPointerRegister(X86::EAX);
    setExceptionSelectorRegister(X86::EDX);
  }
  setOperationAction(ISD::FRAME_TO_ARGS_OFFSET, MVT::i32, Custom);
  setOperationAction(ISD::FRAME_TO_ARGS_OFFSET, MVT::i64, Custom);

  setOperationAction(ISD::TRAMPOLINE, MVT::Other, Custom);

  setOperationAction(ISD::TRAP, MVT::Other, Legal);

  // VASTART needs to be custom lowered to use the VarArgsFrameIndex
  setOperationAction(ISD::VASTART           , MVT::Other, Custom);
  setOperationAction(ISD::VAEND             , MVT::Other, Expand);
  if (Subtarget->is64Bit()) {
    setOperationAction(ISD::VAARG           , MVT::Other, Custom);
    setOperationAction(ISD::VACOPY          , MVT::Other, Custom);
  } else {
    setOperationAction(ISD::VAARG           , MVT::Other, Expand);
    setOperationAction(ISD::VACOPY          , MVT::Other, Expand);
  }

  setOperationAction(ISD::STACKSAVE,          MVT::Other, Expand);
  setOperationAction(ISD::STACKRESTORE,       MVT::Other, Expand);
  if (Subtarget->is64Bit())
    setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64, Expand);
  if (Subtarget->isTargetCygMing())
    setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
  else
    setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);

  if (!UseSoftFloat && X86ScalarSSEf64) {
    // f32 and f64 use SSE.
    // Set up the FP register classes.
    addRegisterClass(MVT::f32, X86::FR32RegisterClass);
    addRegisterClass(MVT::f64, X86::FR64RegisterClass);

    // Use ANDPD to simulate FABS.
    setOperationAction(ISD::FABS , MVT::f64, Custom);
    setOperationAction(ISD::FABS , MVT::f32, Custom);

    // Use XORP to simulate FNEG.
    setOperationAction(ISD::FNEG , MVT::f64, Custom);
    setOperationAction(ISD::FNEG , MVT::f32, Custom);

    // Use ANDPD and ORPD to simulate FCOPYSIGN.
    setOperationAction(ISD::FCOPYSIGN, MVT::f64, Custom);
    setOperationAction(ISD::FCOPYSIGN, MVT::f32, Custom);

    // We don't support sin/cos/fmod
    setOperationAction(ISD::FSIN , MVT::f64, Expand);
    setOperationAction(ISD::FCOS , MVT::f64, Expand);
    setOperationAction(ISD::FSIN , MVT::f32, Expand);
    setOperationAction(ISD::FCOS , MVT::f32, Expand);

    // Expand FP immediates into loads from the stack, except for the special
    // cases we handle.
    addLegalFPImmediate(APFloat(+0.0)); // xorpd
    addLegalFPImmediate(APFloat(+0.0f)); // xorps
  } else if (!UseSoftFloat && X86ScalarSSEf32) {
    // Use SSE for f32, x87 for f64.
    // Set up the FP register classes.
    addRegisterClass(MVT::f32, X86::FR32RegisterClass);
    addRegisterClass(MVT::f64, X86::RFP64RegisterClass);

    // Use ANDPS to simulate FABS.
    setOperationAction(ISD::FABS , MVT::f32, Custom);

    // Use XORP to simulate FNEG.
    setOperationAction(ISD::FNEG , MVT::f32, Custom);

    setOperationAction(ISD::UNDEF,     MVT::f64, Expand);

    // Use ANDPS and ORPS to simulate FCOPYSIGN.
    setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
    setOperationAction(ISD::FCOPYSIGN, MVT::f32, Custom);

    // We don't support sin/cos/fmod
    setOperationAction(ISD::FSIN , MVT::f32, Expand);
    setOperationAction(ISD::FCOS , MVT::f32, Expand);

    // Special cases we handle for FP constants.
    addLegalFPImmediate(APFloat(+0.0f)); // xorps
    addLegalFPImmediate(APFloat(+0.0)); // FLD0
    addLegalFPImmediate(APFloat(+1.0)); // FLD1
    addLegalFPImmediate(APFloat(-0.0)); // FLD0/FCHS
    addLegalFPImmediate(APFloat(-1.0)); // FLD1/FCHS

    if (!UnsafeFPMath) {
      setOperationAction(ISD::FSIN           , MVT::f64  , Expand);
      setOperationAction(ISD::FCOS           , MVT::f64  , Expand);
    }
  } else if (!UseSoftFloat) {
    // f32 and f64 in x87.
    // Set up the FP register classes.
    addRegisterClass(MVT::f64, X86::RFP64RegisterClass);
    addRegisterClass(MVT::f32, X86::RFP32RegisterClass);

    setOperationAction(ISD::UNDEF,     MVT::f64, Expand);
    setOperationAction(ISD::UNDEF,     MVT::f32, Expand);
    setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
    setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);

    if (!UnsafeFPMath) {
      setOperationAction(ISD::FSIN           , MVT::f64  , Expand);
      setOperationAction(ISD::FCOS           , MVT::f64  , Expand);
    }
    addLegalFPImmediate(APFloat(+0.0)); // FLD0
    addLegalFPImmediate(APFloat(+1.0)); // FLD1
    addLegalFPImmediate(APFloat(-0.0)); // FLD0/FCHS
    addLegalFPImmediate(APFloat(-1.0)); // FLD1/FCHS
    addLegalFPImmediate(APFloat(+0.0f)); // FLD0
    addLegalFPImmediate(APFloat(+1.0f)); // FLD1
    addLegalFPImmediate(APFloat(-0.0f)); // FLD0/FCHS
    addLegalFPImmediate(APFloat(-1.0f)); // FLD1/FCHS
  }

  // Long double always uses X87.
  if (!UseSoftFloat) {
    addRegisterClass(MVT::f80, X86::RFP80RegisterClass);
    setOperationAction(ISD::UNDEF,     MVT::f80, Expand);
    setOperationAction(ISD::FCOPYSIGN, MVT::f80, Expand);
    {
      bool ignored;
      APFloat TmpFlt(+0.0);
      TmpFlt.convert(APFloat::x87DoubleExtended, APFloat::rmNearestTiesToEven,
                     &ignored);
      addLegalFPImmediate(TmpFlt);  // FLD0
      TmpFlt.changeSign();
      addLegalFPImmediate(TmpFlt);  // FLD0/FCHS
      APFloat TmpFlt2(+1.0);
      TmpFlt2.convert(APFloat::x87DoubleExtended, APFloat::rmNearestTiesToEven,
                      &ignored);
      addLegalFPImmediate(TmpFlt2);  // FLD1
      TmpFlt2.changeSign();
      addLegalFPImmediate(TmpFlt2);  // FLD1/FCHS
    }

    if (!UnsafeFPMath) {
      setOperationAction(ISD::FSIN           , MVT::f80  , Expand);
      setOperationAction(ISD::FCOS           , MVT::f80  , Expand);
    }
  }

  // Always use a library call for pow.
  setOperationAction(ISD::FPOW             , MVT::f32  , Expand);
  setOperationAction(ISD::FPOW             , MVT::f64  , Expand);
  setOperationAction(ISD::FPOW             , MVT::f80  , Expand);

  setOperationAction(ISD::FLOG, MVT::f80, Expand);
  setOperationAction(ISD::FLOG2, MVT::f80, Expand);
  setOperationAction(ISD::FLOG10, MVT::f80, Expand);
  setOperationAction(ISD::FEXP, MVT::f80, Expand);
  setOperationAction(ISD::FEXP2, MVT::f80, Expand);

  // First set operation action for all vector types to either promote
  // (for widening) or expand (for scalarization). Then we will selectively
  // turn on ones that can be effectively codegen'd.
  for (unsigned VT = (unsigned)MVT::FIRST_VECTOR_VALUETYPE;
       VT <= (unsigned)MVT::LAST_VECTOR_VALUETYPE; ++VT) {
    setOperationAction(ISD::ADD , (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SUB , (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FADD, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FNEG, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FSUB, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::MUL , (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FMUL, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SDIV, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::UDIV, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FDIV, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SREM, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::UREM, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::LOAD, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::VECTOR_SHUFFLE, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT,(MVT::SimpleValueType)VT,Expand);
    setOperationAction(ISD::EXTRACT_SUBVECTOR,(MVT::SimpleValueType)VT,Expand);
    setOperationAction(ISD::INSERT_VECTOR_ELT,(MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FABS, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FSIN, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FCOS, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FREM, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FPOWI, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FSQRT, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FCOPYSIGN, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SMUL_LOHI, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::UMUL_LOHI, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SDIVREM, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::UDIVREM, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FPOW, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::CTPOP, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::CTTZ, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::CTLZ, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SHL, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SRA, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SRL, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::ROTL, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::ROTR, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::BSWAP, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::VSETCC, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FLOG, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FLOG2, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FLOG10, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FEXP, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FEXP2, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FP_TO_UINT, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::FP_TO_SINT, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::UINT_TO_FP, (MVT::SimpleValueType)VT, Expand);
    setOperationAction(ISD::SINT_TO_FP, (MVT::SimpleValueType)VT, Expand);
  }

  // FIXME: In order to prevent SSE instructions being expanded to MMX ones
  // with -msoft-float, disable use of MMX as well.
  if (!UseSoftFloat && !DisableMMX && Subtarget->hasMMX()) {
    addRegisterClass(MVT::v8i8,  X86::VR64RegisterClass);
    addRegisterClass(MVT::v4i16, X86::VR64RegisterClass);
    addRegisterClass(MVT::v2i32, X86::VR64RegisterClass);
    addRegisterClass(MVT::v2f32, X86::VR64RegisterClass);
    addRegisterClass(MVT::v1i64, X86::VR64RegisterClass);

    setOperationAction(ISD::ADD,                MVT::v8i8,  Legal);
    setOperationAction(ISD::ADD,                MVT::v4i16, Legal);
    setOperationAction(ISD::ADD,                MVT::v2i32, Legal);
    setOperationAction(ISD::ADD,                MVT::v1i64, Legal);

    setOperationAction(ISD::SUB,                MVT::v8i8,  Legal);
    setOperationAction(ISD::SUB,                MVT::v4i16, Legal);
    setOperationAction(ISD::SUB,                MVT::v2i32, Legal);
    setOperationAction(ISD::SUB,                MVT::v1i64, Legal);

    setOperationAction(ISD::MULHS,              MVT::v4i16, Legal);
    setOperationAction(ISD::MUL,                MVT::v4i16, Legal);

    setOperationAction(ISD::AND,                MVT::v8i8,  Promote);
    AddPromotedToType (ISD::AND,                MVT::v8i8,  MVT::v1i64);
    setOperationAction(ISD::AND,                MVT::v4i16, Promote);
    AddPromotedToType (ISD::AND,                MVT::v4i16, MVT::v1i64);
    setOperationAction(ISD::AND,                MVT::v2i32, Promote);
    AddPromotedToType (ISD::AND,                MVT::v2i32, MVT::v1i64);
    setOperationAction(ISD::AND,                MVT::v1i64, Legal);

    setOperationAction(ISD::OR,                 MVT::v8i8,  Promote);
    AddPromotedToType (ISD::OR,                 MVT::v8i8,  MVT::v1i64);
    setOperationAction(ISD::OR,                 MVT::v4i16, Promote);
    AddPromotedToType (ISD::OR,                 MVT::v4i16, MVT::v1i64);
    setOperationAction(ISD::OR,                 MVT::v2i32, Promote);
    AddPromotedToType (ISD::OR,                 MVT::v2i32, MVT::v1i64);
    setOperationAction(ISD::OR,                 MVT::v1i64, Legal);

    setOperationAction(ISD::XOR,                MVT::v8i8,  Promote);
    AddPromotedToType (ISD::XOR,                MVT::v8i8,  MVT::v1i64);
    setOperationAction(ISD::XOR,                MVT::v4i16, Promote);
    AddPromotedToType (ISD::XOR,                MVT::v4i16, MVT::v1i64);
    setOperationAction(ISD::XOR,                MVT::v2i32, Promote);
    AddPromotedToType (ISD::XOR,                MVT::v2i32, MVT::v1i64);
    setOperationAction(ISD::XOR,                MVT::v1i64, Legal);

    setOperationAction(ISD::LOAD,               MVT::v8i8,  Promote);
    AddPromotedToType (ISD::LOAD,               MVT::v8i8,  MVT::v1i64);
    setOperationAction(ISD::LOAD,               MVT::v4i16, Promote);
    AddPromotedToType (ISD::LOAD,               MVT::v4i16, MVT::v1i64);
    setOperationAction(ISD::LOAD,               MVT::v2i32, Promote);
    AddPromotedToType (ISD::LOAD,               MVT::v2i32, MVT::v1i64);
    setOperationAction(ISD::LOAD,               MVT::v2f32, Promote);
    AddPromotedToType (ISD::LOAD,               MVT::v2f32, MVT::v1i64);
    setOperationAction(ISD::LOAD,               MVT::v1i64, Legal);

    setOperationAction(ISD::BUILD_VECTOR,       MVT::v8i8,  Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v4i16, Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v2i32, Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v2f32, Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v1i64, Custom);

    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v8i8,  Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v4i16, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v2i32, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v1i64, Custom);

    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v2f32, Custom);
    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v8i8,  Custom);
    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v4i16, Custom);
    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v1i64, Custom);

    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4i16, Custom);

    setTruncStoreAction(MVT::v8i16,             MVT::v8i8, Expand);
    setOperationAction(ISD::TRUNCATE,           MVT::v8i8, Expand);
    setOperationAction(ISD::SELECT,             MVT::v8i8, Promote);
    setOperationAction(ISD::SELECT,             MVT::v4i16, Promote);
    setOperationAction(ISD::SELECT,             MVT::v2i32, Promote);
    setOperationAction(ISD::SELECT,             MVT::v1i64, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v8i8, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v4i16, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v2i32, Custom);
  }

  if (!UseSoftFloat && Subtarget->hasSSE1()) {
    addRegisterClass(MVT::v4f32, X86::VR128RegisterClass);

    setOperationAction(ISD::FADD,               MVT::v4f32, Legal);
    setOperationAction(ISD::FSUB,               MVT::v4f32, Legal);
    setOperationAction(ISD::FMUL,               MVT::v4f32, Legal);
    setOperationAction(ISD::FDIV,               MVT::v4f32, Legal);
    setOperationAction(ISD::FSQRT,              MVT::v4f32, Legal);
    setOperationAction(ISD::FNEG,               MVT::v4f32, Custom);
    setOperationAction(ISD::LOAD,               MVT::v4f32, Legal);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v4f32, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v4f32, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v4f32, Custom);
    setOperationAction(ISD::SELECT,             MVT::v4f32, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v4f32, Custom);
  }

  if (!UseSoftFloat && Subtarget->hasSSE2()) {
    addRegisterClass(MVT::v2f64, X86::VR128RegisterClass);

    // FIXME: Unfortunately -soft-float and -no-implicit-float means XMM
    // registers cannot be used even for integer operations.
    addRegisterClass(MVT::v16i8, X86::VR128RegisterClass);
    addRegisterClass(MVT::v8i16, X86::VR128RegisterClass);
    addRegisterClass(MVT::v4i32, X86::VR128RegisterClass);
    addRegisterClass(MVT::v2i64, X86::VR128RegisterClass);

    setOperationAction(ISD::ADD,                MVT::v16i8, Legal);
    setOperationAction(ISD::ADD,                MVT::v8i16, Legal);
    setOperationAction(ISD::ADD,                MVT::v4i32, Legal);
    setOperationAction(ISD::ADD,                MVT::v2i64, Legal);
    setOperationAction(ISD::MUL,                MVT::v2i64, Custom);
    setOperationAction(ISD::SUB,                MVT::v16i8, Legal);
    setOperationAction(ISD::SUB,                MVT::v8i16, Legal);
    setOperationAction(ISD::SUB,                MVT::v4i32, Legal);
    setOperationAction(ISD::SUB,                MVT::v2i64, Legal);
    setOperationAction(ISD::MUL,                MVT::v8i16, Legal);
    setOperationAction(ISD::FADD,               MVT::v2f64, Legal);
    setOperationAction(ISD::FSUB,               MVT::v2f64, Legal);
    setOperationAction(ISD::FMUL,               MVT::v2f64, Legal);
    setOperationAction(ISD::FDIV,               MVT::v2f64, Legal);
    setOperationAction(ISD::FSQRT,              MVT::v2f64, Legal);
    setOperationAction(ISD::FNEG,               MVT::v2f64, Custom);

    setOperationAction(ISD::VSETCC,             MVT::v2f64, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v16i8, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v8i16, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v4i32, Custom);

    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v16i8, Custom);
    setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v8i16, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v8i16, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4i32, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4f32, Custom);

    // Custom lower build_vector, vector_shuffle, and extract_vector_elt.
    for (unsigned i = (unsigned)MVT::v16i8; i != (unsigned)MVT::v2i64; ++i) {
      MVT VT = (MVT::SimpleValueType)i;
      // Do not attempt to custom lower non-power-of-2 vectors
      if (!isPowerOf2_32(VT.getVectorNumElements()))
        continue;
      // Do not attempt to custom lower non-128-bit vectors
      if (!VT.is128BitVector())
        continue;
      setOperationAction(ISD::BUILD_VECTOR,       VT, Custom);
      setOperationAction(ISD::VECTOR_SHUFFLE,     VT, Custom);
      setOperationAction(ISD::EXTRACT_VECTOR_ELT, VT, Custom);
    }

    setOperationAction(ISD::BUILD_VECTOR,       MVT::v2f64, Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v2i64, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v2f64, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v2i64, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v2f64, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v2f64, Custom);

    if (Subtarget->is64Bit()) {
      setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v2i64, Custom);
      setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v2i64, Custom);
    }

    // Promote v16i8, v8i16, v4i32 load, select, and, or, xor to v2i64.
    for (unsigned i = (unsigned)MVT::v16i8; i != (unsigned)MVT::v2i64; i++) {
      MVT VT = (MVT::SimpleValueType)i;

      // Do not attempt to promote non-128-bit vectors
      if (!VT.is128BitVector()) {
        continue;
      }
      setOperationAction(ISD::AND,    VT, Promote);
      AddPromotedToType (ISD::AND,    VT, MVT::v2i64);
      setOperationAction(ISD::OR,     VT, Promote);
      AddPromotedToType (ISD::OR,     VT, MVT::v2i64);
      setOperationAction(ISD::XOR,    VT, Promote);
      AddPromotedToType (ISD::XOR,    VT, MVT::v2i64);
      setOperationAction(ISD::LOAD,   VT, Promote);
      AddPromotedToType (ISD::LOAD,   VT, MVT::v2i64);
      setOperationAction(ISD::SELECT, VT, Promote);
      AddPromotedToType (ISD::SELECT, VT, MVT::v2i64);
    }

    setTruncStoreAction(MVT::f64, MVT::f32, Expand);

    // Custom lower v2i64 and v2f64 selects.
    setOperationAction(ISD::LOAD,               MVT::v2f64, Legal);
    setOperationAction(ISD::LOAD,               MVT::v2i64, Legal);
    setOperationAction(ISD::SELECT,             MVT::v2f64, Custom);
    setOperationAction(ISD::SELECT,             MVT::v2i64, Custom);

    setOperationAction(ISD::FP_TO_SINT,         MVT::v4i32, Legal);
    setOperationAction(ISD::SINT_TO_FP,         MVT::v4i32, Legal);
    if (!DisableMMX && Subtarget->hasMMX()) {
      setOperationAction(ISD::FP_TO_SINT,         MVT::v2i32, Custom);
      setOperationAction(ISD::SINT_TO_FP,         MVT::v2i32, Custom);
    }
  }

  if (Subtarget->hasSSE41()) {
    // FIXME: Do we need to handle scalar-to-vector here?
    setOperationAction(ISD::MUL,                MVT::v4i32, Legal);

    // i8 and i16 vectors are custom , because the source register and source
    // source memory operand types are not the same width.  f32 vectors are
    // custom since the immediate controlling the insert encodes additional
    // information.
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v16i8, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v8i16, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4i32, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4f32, Custom);

    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v16i8, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v8i16, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v4i32, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v4f32, Custom);

    if (Subtarget->is64Bit()) {
      setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v2i64, Legal);
      setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v2i64, Legal);
    }
  }

  if (Subtarget->hasSSE42()) {
    setOperationAction(ISD::VSETCC,             MVT::v2i64, Custom);
  }

  if (!UseSoftFloat && Subtarget->hasAVX()) {
    addRegisterClass(MVT::v8f32, X86::VR256RegisterClass);
    addRegisterClass(MVT::v4f64, X86::VR256RegisterClass);
    addRegisterClass(MVT::v8i32, X86::VR256RegisterClass);
    addRegisterClass(MVT::v4i64, X86::VR256RegisterClass);

    setOperationAction(ISD::LOAD,               MVT::v8f32, Legal);
    setOperationAction(ISD::LOAD,               MVT::v8i32, Legal);
    setOperationAction(ISD::LOAD,               MVT::v4f64, Legal);
    setOperationAction(ISD::LOAD,               MVT::v4i64, Legal);
    setOperationAction(ISD::FADD,               MVT::v8f32, Legal);
    setOperationAction(ISD::FSUB,               MVT::v8f32, Legal);
    setOperationAction(ISD::FMUL,               MVT::v8f32, Legal);
    setOperationAction(ISD::FDIV,               MVT::v8f32, Legal);
    setOperationAction(ISD::FSQRT,              MVT::v8f32, Legal);
    setOperationAction(ISD::FNEG,               MVT::v8f32, Custom);
    //setOperationAction(ISD::BUILD_VECTOR,       MVT::v8f32, Custom);
    //setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v8f32, Custom);
    //setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v8f32, Custom);
    //setOperationAction(ISD::SELECT,             MVT::v8f32, Custom);
    //setOperationAction(ISD::VSETCC,             MVT::v8f32, Custom);

    // Operations to consider commented out -v16i16 v32i8
    //setOperationAction(ISD::ADD,                MVT::v16i16, Legal);
    setOperationAction(ISD::ADD,                MVT::v8i32, Custom);
    setOperationAction(ISD::ADD,                MVT::v4i64, Custom);
    //setOperationAction(ISD::SUB,                MVT::v32i8, Legal);
    //setOperationAction(ISD::SUB,                MVT::v16i16, Legal);
    setOperationAction(ISD::SUB,                MVT::v8i32, Custom);
    setOperationAction(ISD::SUB,                MVT::v4i64, Custom);
    //setOperationAction(ISD::MUL,                MVT::v16i16, Legal);
    setOperationAction(ISD::FADD,               MVT::v4f64, Legal);
    setOperationAction(ISD::FSUB,               MVT::v4f64, Legal);
    setOperationAction(ISD::FMUL,               MVT::v4f64, Legal);
    setOperationAction(ISD::FDIV,               MVT::v4f64, Legal);
    setOperationAction(ISD::FSQRT,              MVT::v4f64, Legal);
    setOperationAction(ISD::FNEG,               MVT::v4f64, Custom);

    setOperationAction(ISD::VSETCC,             MVT::v4f64, Custom);
    // setOperationAction(ISD::VSETCC,             MVT::v32i8, Custom);
    // setOperationAction(ISD::VSETCC,             MVT::v16i16, Custom);
    setOperationAction(ISD::VSETCC,             MVT::v8i32, Custom);

    // setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v32i8, Custom);
    // setOperationAction(ISD::SCALAR_TO_VECTOR,   MVT::v16i16, Custom);
    // setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v16i16, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v8i32, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v8f32, Custom);

    setOperationAction(ISD::BUILD_VECTOR,       MVT::v4f64, Custom);
    setOperationAction(ISD::BUILD_VECTOR,       MVT::v4i64, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v4f64, Custom);
    setOperationAction(ISD::VECTOR_SHUFFLE,     MVT::v4i64, Custom);
    setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4f64, Custom);
    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v4f64, Custom);

#if 0
    // Not sure we want to do this since there are no 256-bit integer
    // operations in AVX

    // Custom lower build_vector, vector_shuffle, and extract_vector_elt.
    // This includes 256-bit vectors
    for (unsigned i = (unsigned)MVT::v16i8; i != (unsigned)MVT::v4i64; ++i) {
      MVT VT = (MVT::SimpleValueType)i;

      // Do not attempt to custom lower non-power-of-2 vectors
      if (!isPowerOf2_32(VT.getVectorNumElements()))
        continue;

      setOperationAction(ISD::BUILD_VECTOR,       VT, Custom);
      setOperationAction(ISD::VECTOR_SHUFFLE,     VT, Custom);
      setOperationAction(ISD::EXTRACT_VECTOR_ELT, VT, Custom);
    }

    if (Subtarget->is64Bit()) {
      setOperationAction(ISD::INSERT_VECTOR_ELT,  MVT::v4i64, Custom);
      setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v4i64, Custom);
    }    
#endif

#if 0
    // Not sure we want to do this since there are no 256-bit integer
    // operations in AVX

    // Promote v32i8, v16i16, v8i32 load, select, and, or, xor to v4i64.
    // Including 256-bit vectors
    for (unsigned i = (unsigned)MVT::v16i8; i != (unsigned)MVT::v4i64; i++) {
      MVT VT = (MVT::SimpleValueType)i;

      if (!VT.is256BitVector()) {
        continue;
      }
      setOperationAction(ISD::AND,    VT, Promote);
      AddPromotedToType (ISD::AND,    VT, MVT::v4i64);
      setOperationAction(ISD::OR,     VT, Promote);
      AddPromotedToType (ISD::OR,     VT, MVT::v4i64);
      setOperationAction(ISD::XOR,    VT, Promote);
      AddPromotedToType (ISD::XOR,    VT, MVT::v4i64);
      setOperationAction(ISD::LOAD,   VT, Promote);
      AddPromotedToType (ISD::LOAD,   VT, MVT::v4i64);
      setOperationAction(ISD::SELECT, VT, Promote);
      AddPromotedToType (ISD::SELECT, VT, MVT::v4i64);
    }

    setTruncStoreAction(MVT::f64, MVT::f32, Expand);
#endif
  }

  // We want to custom lower some of our intrinsics.
  setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);

  // Add/Sub/Mul with overflow operations are custom lowered.
  setOperationAction(ISD::SADDO, MVT::i32, Custom);
  setOperationAction(ISD::SADDO, MVT::i64, Custom);
  setOperationAction(ISD::UADDO, MVT::i32, Custom);
  setOperationAction(ISD::UADDO, MVT::i64, Custom);
  setOperationAction(ISD::SSUBO, MVT::i32, Custom);
  setOperationAction(ISD::SSUBO, MVT::i64, Custom);
  setOperationAction(ISD::USUBO, MVT::i32, Custom);
  setOperationAction(ISD::USUBO, MVT::i64, Custom);
  setOperationAction(ISD::SMULO, MVT::i32, Custom);
  setOperationAction(ISD::SMULO, MVT::i64, Custom);

  if (!Subtarget->is64Bit()) {
    // These libcalls are not available in 32-bit.
    setLibcallName(RTLIB::SHL_I128, 0);
    setLibcallName(RTLIB::SRL_I128, 0);
    setLibcallName(RTLIB::SRA_I128, 0);
  }

  // We have target-specific dag combine patterns for the following nodes:
  setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
  setTargetDAGCombine(ISD::BUILD_VECTOR);
  setTargetDAGCombine(ISD::SELECT);
  setTargetDAGCombine(ISD::SHL);
  setTargetDAGCombine(ISD::SRA);
  setTargetDAGCombine(ISD::SRL);
  setTargetDAGCombine(ISD::STORE);
  setTargetDAGCombine(ISD::MEMBARRIER);
  if (Subtarget->is64Bit())
    setTargetDAGCombine(ISD::MUL);

  computeRegisterProperties();

  // FIXME: These should be based on subtarget info. Plus, the values should
  // be smaller when we are in optimizing for size mode.
  maxStoresPerMemset = 16; // For @llvm.memset -> sequence of stores
  maxStoresPerMemcpy = 16; // For @llvm.memcpy -> sequence of stores
  maxStoresPerMemmove = 3; // For @llvm.memmove -> sequence of stores
  allowUnalignedMemoryAccesses = true; // x86 supports it!
  setPrefLoopAlignment(16);
  benefitFromCodePlacementOpt = true;
}


MVT X86TargetLowering::getSetCCResultType(MVT VT) const {
  return MVT::i8;
}


/// getMaxByValAlign - Helper for getByValTypeAlignment to determine
/// the desired ByVal argument alignment.
static void getMaxByValAlign(const Type *Ty, unsigned &MaxAlign) {
  if (MaxAlign == 16)
    return;
  if (const VectorType *VTy = dyn_cast<VectorType>(Ty)) {
    if (VTy->getBitWidth() == 128)
      MaxAlign = 16;
  } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
    unsigned EltAlign = 0;
    getMaxByValAlign(ATy->getElementType(), EltAlign);
    if (EltAlign > MaxAlign)
      MaxAlign = EltAlign;
  } else if (const StructType *STy = dyn_cast<StructType>(Ty)) {
    for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
      unsigned EltAlign = 0;
      getMaxByValAlign(STy->getElementType(i), EltAlign);
      if (EltAlign > MaxAlign)
        MaxAlign = EltAlign;
      if (MaxAlign == 16)
        break;
    }
  }
  return;
}

/// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
/// function arguments in the caller parameter area. For X86, aggregates
/// that contain SSE vectors are placed at 16-byte boundaries while the rest
/// are at 4-byte boundaries.
unsigned X86TargetLowering::getByValTypeAlignment(const Type *Ty) const {
  if (Subtarget->is64Bit()) {
    // Max of 8 and alignment of type.
    unsigned TyAlign = TD->getABITypeAlignment(Ty);
    if (TyAlign > 8)
      return TyAlign;
    return 8;
  }

  unsigned Align = 4;
  if (Subtarget->hasSSE1())
    getMaxByValAlign(Ty, Align);
  return Align;
}

/// getOptimalMemOpType - Returns the target specific optimal type for load
/// and store operations as a result of memset, memcpy, and memmove
/// lowering. It returns MVT::iAny if SelectionDAG should be responsible for
/// determining it.
MVT
X86TargetLowering::getOptimalMemOpType(uint64_t Size, unsigned Align,
                                       bool isSrcConst, bool isSrcStr,
                                       SelectionDAG &DAG) const {
  // FIXME: This turns off use of xmm stores for memset/memcpy on targets like
  // linux.  This is because the stack realignment code can't handle certain
  // cases like PR2962.  This should be removed when PR2962 is fixed.
  const Function *F = DAG.getMachineFunction().getFunction();
  bool NoImplicitFloatOps = F->hasFnAttr(Attribute::NoImplicitFloat);
  if (!NoImplicitFloatOps && Subtarget->getStackAlignment() >= 16) {
    if ((isSrcConst || isSrcStr) && Subtarget->hasSSE2() && Size >= 16)
      return MVT::v4i32;
    if ((isSrcConst || isSrcStr) && Subtarget->hasSSE1() && Size >= 16)
      return MVT::v4f32;
  }
  if (Subtarget->is64Bit() && Size >= 8)
    return MVT::i64;
  return MVT::i32;
}

/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
SDValue X86TargetLowering::getPICJumpTableRelocBase(SDValue Table,
                                                      SelectionDAG &DAG) const {
  if (usesGlobalOffsetTable())
    return DAG.getGLOBAL_OFFSET_TABLE(getPointerTy());
  if (!Subtarget->is64Bit())
    // This doesn't have DebugLoc associated with it, but is not really the
    // same as a Register.
    return DAG.getNode(X86ISD::GlobalBaseReg, DebugLoc::getUnknownLoc(),
                       getPointerTy());
  return Table;
}

/// getFunctionAlignment - Return the Log2 alignment of this function.
unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
  return F->hasFnAttr(Attribute::OptimizeForSize) ? 1 : 4;
}

//===----------------------------------------------------------------------===//
//               Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//

#include "X86GenCallingConv.inc"

/// LowerRET - Lower an ISD::RET node.
SDValue X86TargetLowering::LowerRET(SDValue Op, SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();
  assert((Op.getNumOperands() & 1) == 1 && "ISD::RET should have odd # args");

  SmallVector<CCValAssign, 16> RVLocs;
  unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
  bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
  CCState CCInfo(CC, isVarArg, getTargetMachine(), RVLocs, *DAG.getContext());
  CCInfo.AnalyzeReturn(Op.getNode(), RetCC_X86);

  // If this is the first return lowered for this function, add the regs to the
  // liveout set for the function.
  if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
    for (unsigned i = 0; i != RVLocs.size(); ++i)
      if (RVLocs[i].isRegLoc())
        DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
  }
  SDValue Chain = Op.getOperand(0);

  // Handle tail call return.
  Chain = GetPossiblePreceedingTailCall(Chain, X86ISD::TAILCALL);
  if (Chain.getOpcode() == X86ISD::TAILCALL) {
    SDValue TailCall = Chain;
    SDValue TargetAddress = TailCall.getOperand(1);
    SDValue StackAdjustment = TailCall.getOperand(2);
    assert(((TargetAddress.getOpcode() == ISD::Register &&
               (cast<RegisterSDNode>(TargetAddress)->getReg() == X86::EAX ||
                cast<RegisterSDNode>(TargetAddress)->getReg() == X86::R11)) ||
              TargetAddress.getOpcode() == ISD::TargetExternalSymbol ||
              TargetAddress.getOpcode() == ISD::TargetGlobalAddress) &&
             "Expecting an global address, external symbol, or register");
    assert(StackAdjustment.getOpcode() == ISD::Constant &&
           "Expecting a const value");

    SmallVector<SDValue,8> Operands;
    Operands.push_back(Chain.getOperand(0));
    Operands.push_back(TargetAddress);
    Operands.push_back(StackAdjustment);
    // Copy registers used by the call. Last operand is a flag so it is not
    // copied.
    for (unsigned i=3; i < TailCall.getNumOperands()-1; i++) {
      Operands.push_back(Chain.getOperand(i));
    }
    return DAG.getNode(X86ISD::TC_RETURN, dl, MVT::Other, &Operands[0],
                       Operands.size());
  }

  // Regular return.
  SDValue Flag;

  SmallVector<SDValue, 6> RetOps;
  RetOps.push_back(Chain); // Operand #0 = Chain (updated below)
  // Operand #1 = Bytes To Pop
  RetOps.push_back(DAG.getConstant(getBytesToPopOnReturn(), MVT::i16));

  // Copy the result values into the output registers.
  for (unsigned i = 0; i != RVLocs.size(); ++i) {
    CCValAssign &VA = RVLocs[i];
    assert(VA.isRegLoc() && "Can only return in registers!");
    SDValue ValToCopy = Op.getOperand(i*2+1);

    // Returns in ST0/ST1 are handled specially: these are pushed as operands to
    // the RET instruction and handled by the FP Stackifier.
    if (VA.getLocReg() == X86::ST0 ||
        VA.getLocReg() == X86::ST1) {
      // If this is a copy from an xmm register to ST(0), use an FPExtend to
      // change the value to the FP stack register class.
      if (isScalarFPTypeInSSEReg(VA.getValVT()))
        ValToCopy = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f80, ValToCopy);
      RetOps.push_back(ValToCopy);
      // Don't emit a copytoreg.
      continue;
    }

    // 64-bit vector (MMX) values are returned in XMM0 / XMM1 except for v1i64
    // which is returned in RAX / RDX.
    if (Subtarget->is64Bit()) {
      MVT ValVT = ValToCopy.getValueType();
      if (ValVT.isVector() && ValVT.getSizeInBits() == 64) {
        ValToCopy = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, ValToCopy);
        if (VA.getLocReg() == X86::XMM0 || VA.getLocReg() == X86::XMM1)
          ValToCopy = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2i64, ValToCopy);
      }
    }

    Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), ValToCopy, Flag);
    Flag = Chain.getValue(1);
  }

  // The x86-64 ABI for returning structs by value requires that we copy
  // the sret argument into %rax for the return. We saved the argument into
  // a virtual register in the entry block, so now we copy the value out
  // and into %rax.
  if (Subtarget->is64Bit() &&
      DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
    MachineFunction &MF = DAG.getMachineFunction();
    X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
    unsigned Reg = FuncInfo->getSRetReturnReg();
    if (!Reg) {
      Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
      FuncInfo->setSRetReturnReg(Reg);
    }
    SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy());

    Chain = DAG.getCopyToReg(Chain, dl, X86::RAX, Val, Flag);
    Flag = Chain.getValue(1);
  }

  RetOps[0] = Chain;  // Update chain.

  // Add the flag if we have it.
  if (Flag.getNode())
    RetOps.push_back(Flag);

  return DAG.getNode(X86ISD::RET_FLAG, dl,
                     MVT::Other, &RetOps[0], RetOps.size());
}


/// LowerCallResult - Lower the result values of an ISD::CALL into the
/// appropriate copies out of appropriate physical registers.  This assumes that
/// Chain/InFlag are the input chain/flag to use, and that TheCall is the call
/// being lowered.  The returns a SDNode with the same number of values as the
/// ISD::CALL.
SDNode *X86TargetLowering::
LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall,
                unsigned CallingConv, SelectionDAG &DAG) {

  DebugLoc dl = TheCall->getDebugLoc();
  // Assign locations to each value returned by this call.
  SmallVector<CCValAssign, 16> RVLocs;
  bool isVarArg = TheCall->isVarArg();
  bool Is64Bit = Subtarget->is64Bit();
  CCState CCInfo(CallingConv, isVarArg, getTargetMachine(),
                 RVLocs, *DAG.getContext());
  CCInfo.AnalyzeCallResult(TheCall, RetCC_X86);

  SmallVector<SDValue, 8> ResultVals;

  // Copy all of the result registers out of their specified physreg.
  for (unsigned i = 0; i != RVLocs.size(); ++i) {
    CCValAssign &VA = RVLocs[i];
    MVT CopyVT = VA.getValVT();

    // If this is x86-64, and we disabled SSE, we can't return FP values
    if ((CopyVT == MVT::f32 || CopyVT == MVT::f64) &&
        ((Is64Bit || TheCall->isInreg()) && !Subtarget->hasSSE1())) {
      llvm_report_error("SSE register return with SSE disabled");
    }

    // If this is a call to a function that returns an fp value on the floating
    // point stack, but where we prefer to use the value in xmm registers, copy
    // it out as F80 and use a truncate to move it from fp stack reg to xmm reg.
    if ((VA.getLocReg() == X86::ST0 ||
         VA.getLocReg() == X86::ST1) &&
        isScalarFPTypeInSSEReg(VA.getValVT())) {
      CopyVT = MVT::f80;
    }

    SDValue Val;
    if (Is64Bit && CopyVT.isVector() && CopyVT.getSizeInBits() == 64) {
      // For x86-64, MMX values are returned in XMM0 / XMM1 except for v1i64.
      if (VA.getLocReg() == X86::XMM0 || VA.getLocReg() == X86::XMM1) {
        Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
                                   MVT::v2i64, InFlag).getValue(1);
        Val = Chain.getValue(0);
        Val = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i64,
                          Val, DAG.getConstant(0, MVT::i64));
      } else {
        Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
                                   MVT::i64, InFlag).getValue(1);
        Val = Chain.getValue(0);
      }
      Val = DAG.getNode(ISD::BIT_CONVERT, dl, CopyVT, Val);
    } else {
      Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
                                 CopyVT, InFlag).getValue(1);
      Val = Chain.getValue(0);
    }
    InFlag = Chain.getValue(2);

    if (CopyVT != VA.getValVT()) {
      // Round the F80 the right size, which also moves to the appropriate xmm
      // register.
      Val = DAG.getNode(ISD::FP_ROUND, dl, VA.getValVT(), Val,
                        // This truncation won't change the value.
                        DAG.getIntPtrConstant(1));
    }

    ResultVals.push_back(Val);
  }

  // Merge everything together with a MERGE_VALUES node.
  ResultVals.push_back(Chain);
  return DAG.getNode(ISD::MERGE_VALUES, dl, TheCall->getVTList(),
                     &ResultVals[0], ResultVals.size()).getNode();
}


//===----------------------------------------------------------------------===//
//                C & StdCall & Fast Calling Convention implementation
//===----------------------------------------------------------------------===//
//  StdCall calling convention seems to be standard for many Windows' API
//  routines and around. It differs from C calling convention just a little:
//  callee should clean up the stack, not caller. Symbols should be also
//  decorated in some fancy way :) It doesn't support any vector arguments.
//  For info on fast calling convention see Fast Calling Convention (tail call)
//  implementation LowerX86_32FastCCCallTo.

/// CallIsStructReturn - Determines whether a CALL node uses struct return
/// semantics.
static bool CallIsStructReturn(CallSDNode *TheCall) {
  unsigned NumOps = TheCall->getNumArgs();
  if (!NumOps)
    return false;

  return TheCall->getArgFlags(0).isSRet();
}

/// ArgsAreStructReturn - Determines whether a function uses struct
/// return semantics.
static bool ArgsAreStructReturn(SDValue Op) {
  unsigned NumArgs = Op.getNode()->getNumValues() - 1;
  if (!NumArgs)
    return false;

  return cast<ARG_FLAGSSDNode>(Op.getOperand(3))->getArgFlags().isSRet();
}

/// IsCalleePop - Determines whether the callee is required to pop its
/// own arguments. Callee pop is necessary to support tail calls.
bool X86TargetLowering::IsCalleePop(bool IsVarArg, unsigned CallingConv) {
  if (IsVarArg)
    return false;

  switch (CallingConv) {
  default:
    return false;
  case CallingConv::X86_StdCall:
    return !Subtarget->is64Bit();
  case CallingConv::X86_FastCall:
    return !Subtarget->is64Bit();
  case CallingConv::Fast:
    return PerformTailCallOpt;
  }
}

/// CCAssignFnForNode - Selects the correct CCAssignFn for a the
/// given CallingConvention value.
CCAssignFn *X86TargetLowering::CCAssignFnForNode(unsigned CC) const {
  if (Subtarget->is64Bit()) {
    if (Subtarget->isTargetWin64())
      return CC_X86_Win64_C;
    else
      return CC_X86_64_C;
  }

  if (CC == CallingConv::X86_FastCall)
    return CC_X86_32_FastCall;
  else if (CC == CallingConv::Fast)
    return CC_X86_32_FastCC;
  else
    return CC_X86_32_C;
}

/// NameDecorationForFORMAL_ARGUMENTS - Selects the appropriate decoration to
/// apply to a MachineFunction containing a given FORMAL_ARGUMENTS node.
NameDecorationStyle
X86TargetLowering::NameDecorationForFORMAL_ARGUMENTS(SDValue Op) {
  unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
  if (CC == CallingConv::X86_FastCall)
    return FastCall;
  else if (CC == CallingConv::X86_StdCall)
    return StdCall;
  return None;
}


/// CreateCopyOfByValArgument - Make a copy of an aggregate at address specified
/// by "Src" to address "Dst" with size and alignment information specified by
/// the specific parameter attribute. The copy will be passed as a byval
/// function parameter.
static SDValue
CreateCopyOfByValArgument(SDValue Src, SDValue Dst, SDValue Chain,
                          ISD::ArgFlagsTy Flags, SelectionDAG &DAG,
                          DebugLoc dl) {
  SDValue SizeNode     = DAG.getConstant(Flags.getByValSize(), MVT::i32);
  return DAG.getMemcpy(Chain, dl, Dst, Src, SizeNode, Flags.getByValAlign(),
                       /*AlwaysInline=*/true, NULL, 0, NULL, 0);
}

SDValue X86TargetLowering::LowerMemArgument(SDValue Op, SelectionDAG &DAG,
                                              const CCValAssign &VA,
                                              MachineFrameInfo *MFI,
                                              unsigned CC,
                                              SDValue Root, unsigned i) {
  // Create the nodes corresponding to a load from this parameter slot.
  ISD::ArgFlagsTy Flags =
    cast<ARG_FLAGSSDNode>(Op.getOperand(3 + i))->getArgFlags();
  bool AlwaysUseMutable = (CC==CallingConv::Fast) && PerformTailCallOpt;
  bool isImmutable = !AlwaysUseMutable && !Flags.isByVal();

  // FIXME: For now, all byval parameter objects are marked mutable. This can be
  // changed with more analysis.
  // In case of tail call optimization mark all arguments mutable. Since they
  // could be overwritten by lowering of arguments in case of a tail call.
  int FI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
                                  VA.getLocMemOffset(), isImmutable);
  SDValue FIN = DAG.getFrameIndex(FI, getPointerTy());
  if (Flags.isByVal())
    return FIN;
  return DAG.getLoad(VA.getValVT(), Op.getDebugLoc(), Root, FIN,
                     PseudoSourceValue::getFixedStack(FI), 0);
}

SDValue
X86TargetLowering::LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG) {
  MachineFunction &MF = DAG.getMachineFunction();
  X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
  DebugLoc dl = Op.getDebugLoc();

  const Function* Fn = MF.getFunction();
  if (Fn->hasExternalLinkage() &&
      Subtarget->isTargetCygMing() &&
      Fn->getName() == "main")
    FuncInfo->setForceFramePointer(true);

  // Decorate the function name.
  FuncInfo->setDecorationStyle(NameDecorationForFORMAL_ARGUMENTS(Op));

  MachineFrameInfo *MFI = MF.getFrameInfo();
  SDValue Root = Op.getOperand(0);
  bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
  unsigned CC = MF.getFunction()->getCallingConv();
  bool Is64Bit = Subtarget->is64Bit();
  bool IsWin64 = Subtarget->isTargetWin64();

  assert(!(isVarArg && CC == CallingConv::Fast) &&
         "Var args not supported with calling convention fastcc");

  // Assign locations to all of the incoming arguments.
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs, *DAG.getContext());
  CCInfo.AnalyzeFormalArguments(Op.getNode(), CCAssignFnForNode(CC));

  SmallVector<SDValue, 8> ArgValues;
  unsigned LastVal = ~0U;
  SDValue ArgValue;
  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    CCValAssign &VA = ArgLocs[i];
    // TODO: If an arg is passed in two places (e.g. reg and stack), skip later
    // places.
    assert(VA.getValNo() != LastVal &&
           "Don't support value assigned to multiple locs yet");
    LastVal = VA.getValNo();

    if (VA.isRegLoc()) {
      MVT RegVT = VA.getLocVT();
      TargetRegisterClass *RC = NULL;
      if (RegVT == MVT::i32)
        RC = X86::GR32RegisterClass;
      else if (Is64Bit && RegVT == MVT::i64)
        RC = X86::GR64RegisterClass;
      else if (RegVT == MVT::f32)
        RC = X86::FR32RegisterClass;
      else if (RegVT == MVT::f64)
        RC = X86::FR64RegisterClass;
      else if (RegVT.isVector() && RegVT.getSizeInBits() == 128)
        RC = X86::VR128RegisterClass;
      else if (RegVT.isVector() && RegVT.getSizeInBits() == 64)
        RC = X86::VR64RegisterClass;
      else
        llvm_unreachable("Unknown argument type!");

      unsigned Reg = MF.addLiveIn(VA.getLocReg(), RC);
      ArgValue = DAG.getCopyFromReg(Root, dl, Reg, RegVT);

      // If this is an 8 or 16-bit value, it is really passed promoted to 32
      // bits.  Insert an assert[sz]ext to capture this, then truncate to the
      // right size.
      if (VA.getLocInfo() == CCValAssign::SExt)
        ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
                               DAG.getValueType(VA.getValVT()));
      else if (VA.getLocInfo() == CCValAssign::ZExt)
        ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
                               DAG.getValueType(VA.getValVT()));
      else if (VA.getLocInfo() == CCValAssign::BCvt)
        ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getValVT(), ArgValue);

      if (VA.isExtInLoc()) {
        // Handle MMX values passed in XMM regs.
        if (RegVT.isVector()) {
          ArgValue = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i64,
                                 ArgValue, DAG.getConstant(0, MVT::i64));
          ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getValVT(), ArgValue);
        } else
          ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
      }
    } else {
      assert(VA.isMemLoc());
      ArgValue = LowerMemArgument(Op, DAG, VA, MFI, CC, Root, i);
    }

    // If value is passed via pointer - do a load.
    if (VA.getLocInfo() == CCValAssign::Indirect)
      ArgValue = DAG.getLoad(VA.getValVT(), dl, Root, ArgValue, NULL, 0);

    ArgValues.push_back(ArgValue);
  }

  // The x86-64 ABI for returning structs by value requires that we copy
  // the sret argument into %rax for the return. Save the argument into
  // a virtual register so that we can access it from the return points.
  if (Is64Bit && MF.getFunction()->hasStructRetAttr()) {
    X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
    unsigned Reg = FuncInfo->getSRetReturnReg();
    if (!Reg) {
      Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
      FuncInfo->setSRetReturnReg(Reg);
    }
    SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, ArgValues[0]);
    Root = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Root);
  }

  unsigned StackSize = CCInfo.getNextStackOffset();
  // align stack specially for tail calls
  if (PerformTailCallOpt && CC == CallingConv::Fast)
    StackSize = GetAlignedArgumentStackSize(StackSize, DAG);

  // If the function takes variable number of arguments, make a frame index for
  // the start of the first vararg value... for expansion of llvm.va_start.
  if (isVarArg) {
    if (Is64Bit || CC != CallingConv::X86_FastCall) {
      VarArgsFrameIndex = MFI->CreateFixedObject(1, StackSize);
    }
    if (Is64Bit) {
      unsigned TotalNumIntRegs = 0, TotalNumXMMRegs = 0;

      // FIXME: We should really autogenerate these arrays
      static const unsigned GPR64ArgRegsWin64[] = {
        X86::RCX, X86::RDX, X86::R8,  X86::R9
      };
      static const unsigned XMMArgRegsWin64[] = {
        X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3
      };
      static const unsigned GPR64ArgRegs64Bit[] = {
        X86::RDI, X86::RSI, X86::RDX, X86::RCX, X86::R8, X86::R9
      };
      static const unsigned XMMArgRegs64Bit[] = {
        X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
        X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7
      };
      const unsigned *GPR64ArgRegs, *XMMArgRegs;

      if (IsWin64) {
        TotalNumIntRegs = 4; TotalNumXMMRegs = 4;
        GPR64ArgRegs = GPR64ArgRegsWin64;
        XMMArgRegs = XMMArgRegsWin64;
      } else {
        TotalNumIntRegs = 6; TotalNumXMMRegs = 8;
        GPR64ArgRegs = GPR64ArgRegs64Bit;
        XMMArgRegs = XMMArgRegs64Bit;
      }
      unsigned NumIntRegs = CCInfo.getFirstUnallocated(GPR64ArgRegs,
                                                       TotalNumIntRegs);
      unsigned NumXMMRegs = CCInfo.getFirstUnallocated(XMMArgRegs,
                                                       TotalNumXMMRegs);

      bool NoImplicitFloatOps = Fn->hasFnAttr(Attribute::NoImplicitFloat);
      assert(!(NumXMMRegs && !Subtarget->hasSSE1()) &&
             "SSE register cannot be used when SSE is disabled!");
      assert(!(NumXMMRegs && UseSoftFloat && NoImplicitFloatOps) &&
             "SSE register cannot be used when SSE is disabled!");
      if (UseSoftFloat || NoImplicitFloatOps || !Subtarget->hasSSE1())
        // Kernel mode asks for SSE to be disabled, so don't push them
        // on the stack.
        TotalNumXMMRegs = 0;

      // For X86-64, if there are vararg parameters that are passed via
      // registers, then we must store them to their spots on the stack so they
      // may be loaded by deferencing the result of va_next.
      VarArgsGPOffset = NumIntRegs * 8;
      VarArgsFPOffset = TotalNumIntRegs * 8 + NumXMMRegs * 16;
      RegSaveFrameIndex = MFI->CreateStackObject(TotalNumIntRegs * 8 +
                                                 TotalNumXMMRegs * 16, 16);

      // Store the integer parameter registers.
      SmallVector<SDValue, 8> MemOps;
      SDValue RSFIN = DAG.getFrameIndex(RegSaveFrameIndex, getPointerTy());
      SDValue FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(), RSFIN,
                                  DAG.getIntPtrConstant(VarArgsGPOffset));
      for (; NumIntRegs != TotalNumIntRegs; ++NumIntRegs) {
        unsigned VReg = MF.addLiveIn(GPR64ArgRegs[NumIntRegs],
                                     X86::GR64RegisterClass);
        SDValue Val = DAG.getCopyFromReg(Root, dl, VReg, MVT::i64);
        SDValue Store =
          DAG.getStore(Val.getValue(1), dl, Val, FIN,
                       PseudoSourceValue::getFixedStack(RegSaveFrameIndex), 0);
        MemOps.push_back(Store);
        FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(), FIN,
                          DAG.getIntPtrConstant(8));
      }

      // Now store the XMM (fp + vector) parameter registers.
      FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(), RSFIN,
                        DAG.getIntPtrConstant(VarArgsFPOffset));
      for (; NumXMMRegs != TotalNumXMMRegs; ++NumXMMRegs) {
        unsigned VReg = MF.addLiveIn(XMMArgRegs[NumXMMRegs],
                                     X86::VR128RegisterClass);
        SDValue Val = DAG.getCopyFromReg(Root, dl, VReg, MVT::v4f32);
        SDValue Store =
          DAG.getStore(Val.getValue(1), dl, Val, FIN,
                       PseudoSourceValue::getFixedStack(RegSaveFrameIndex), 0);
        MemOps.push_back(Store);
        FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(), FIN,
                          DAG.getIntPtrConstant(16));
      }
      if (!MemOps.empty())
          Root = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                             &MemOps[0], MemOps.size());
    }
  }

  ArgValues.push_back(Root);

  // Some CCs need callee pop.
  if (IsCalleePop(isVarArg, CC)) {
    BytesToPopOnReturn  = StackSize; // Callee pops everything.
    BytesCallerReserves = 0;
  } else {
    BytesToPopOnReturn  = 0; // Callee pops nothing.
    // If this is an sret function, the return should pop the hidden pointer.
    if (!Is64Bit && CC != CallingConv::Fast && ArgsAreStructReturn(Op))
      BytesToPopOnReturn = 4;
    BytesCallerReserves = StackSize;
  }

  if (!Is64Bit) {
    RegSaveFrameIndex = 0xAAAAAAA;   // RegSaveFrameIndex is X86-64 only.
    if (CC == CallingConv::X86_FastCall)
      VarArgsFrameIndex = 0xAAAAAAA;   // fastcc functions can't have varargs.
  }

  FuncInfo->setBytesToPopOnReturn(BytesToPopOnReturn);

  // Return the new list of results.
  return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getNode()->getVTList(),
                     &ArgValues[0], ArgValues.size()).getValue(Op.getResNo());
}

SDValue
X86TargetLowering::LowerMemOpCallTo(CallSDNode *TheCall, SelectionDAG &DAG,
                                    const SDValue &StackPtr,
                                    const CCValAssign &VA,
                                    SDValue Chain,
                                    SDValue Arg, ISD::ArgFlagsTy Flags) {
  const unsigned FirstStackArgOffset = (Subtarget->isTargetWin64() ? 32 : 0);
  DebugLoc dl = TheCall->getDebugLoc();
  unsigned LocMemOffset = FirstStackArgOffset + VA.getLocMemOffset();
  SDValue PtrOff = DAG.getIntPtrConstant(LocMemOffset);
  PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(), StackPtr, PtrOff);
  if (Flags.isByVal()) {
    return CreateCopyOfByValArgument(Arg, PtrOff, Chain, Flags, DAG, dl);
  }
  return DAG.getStore(Chain, dl, Arg, PtrOff,
                      PseudoSourceValue::getStack(), LocMemOffset);
}

/// EmitTailCallLoadRetAddr - Emit a load of return address if tail call
/// optimization is performed and it is required.
SDValue
X86TargetLowering::EmitTailCallLoadRetAddr(SelectionDAG &DAG,
                                           SDValue &OutRetAddr,
                                           SDValue Chain,
                                           bool IsTailCall,
                                           bool Is64Bit,
                                           int FPDiff,
                                           DebugLoc dl) {
  if (!IsTailCall || FPDiff==0) return Chain;

  // Adjust the Return address stack slot.
  MVT VT = getPointerTy();
  OutRetAddr = getReturnAddressFrameIndex(DAG);

  // Load the "old" Return address.
  OutRetAddr = DAG.getLoad(VT, dl, Chain, OutRetAddr, NULL, 0);
  return SDValue(OutRetAddr.getNode(), 1);
}

/// EmitTailCallStoreRetAddr - Emit a store of the return adress if tail call
/// optimization is performed and it is required (FPDiff!=0).
static SDValue
EmitTailCallStoreRetAddr(SelectionDAG & DAG, MachineFunction &MF,
                         SDValue Chain, SDValue RetAddrFrIdx,
                         bool Is64Bit, int FPDiff, DebugLoc dl) {
  // Store the return address to the appropriate stack slot.
  if (!FPDiff) return Chain;
  // Calculate the new stack slot for the return address.
  int SlotSize = Is64Bit ? 8 : 4;
  int NewReturnAddrFI =
    MF.getFrameInfo()->CreateFixedObject(SlotSize, FPDiff-SlotSize);
  MVT VT = Is64Bit ? MVT::i64 : MVT::i32;
  SDValue NewRetAddrFrIdx = DAG.getFrameIndex(NewReturnAddrFI, VT);
  Chain = DAG.getStore(Chain, dl, RetAddrFrIdx, NewRetAddrFrIdx,
                       PseudoSourceValue::getFixedStack(NewReturnAddrFI), 0);
  return Chain;
}

SDValue X86TargetLowering::LowerCALL(SDValue Op, SelectionDAG &DAG) {
  MachineFunction &MF = DAG.getMachineFunction();
  CallSDNode *TheCall = cast<CallSDNode>(Op.getNode());
  SDValue Chain       = TheCall->getChain();
  unsigned CC         = TheCall->getCallingConv();
  bool isVarArg       = TheCall->isVarArg();
  bool IsTailCall     = TheCall->isTailCall() &&
                        CC == CallingConv::Fast && PerformTailCallOpt;
  SDValue Callee      = TheCall->getCallee();
  bool Is64Bit        = Subtarget->is64Bit();
  bool IsStructRet    = CallIsStructReturn(TheCall);
  DebugLoc dl         = TheCall->getDebugLoc();

  assert(!(isVarArg && CC == CallingConv::Fast) &&
         "Var args not supported with calling convention fastcc");

  // Analyze operands of the call, assigning locations to each operand.
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs, *DAG.getContext());
  CCInfo.AnalyzeCallOperands(TheCall, CCAssignFnForNode(CC));

  // Get a count of how many bytes are to be pushed on the stack.
  unsigned NumBytes = CCInfo.getNextStackOffset();
  if (PerformTailCallOpt && CC == CallingConv::Fast)
    NumBytes = GetAlignedArgumentStackSize(NumBytes, DAG);

  int FPDiff = 0;
  if (IsTailCall) {
    // Lower arguments at fp - stackoffset + fpdiff.
    unsigned NumBytesCallerPushed =
      MF.getInfo<X86MachineFunctionInfo>()->getBytesToPopOnReturn();
    FPDiff = NumBytesCallerPushed - NumBytes;

    // Set the delta of movement of the returnaddr stackslot.
    // But only set if delta is greater than previous delta.
    if (FPDiff < (MF.getInfo<X86MachineFunctionInfo>()->getTCReturnAddrDelta()))
      MF.getInfo<X86MachineFunctionInfo>()->setTCReturnAddrDelta(FPDiff);
  }

  Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true));

  SDValue RetAddrFrIdx;
  // Load return adress for tail calls.
  Chain = EmitTailCallLoadRetAddr(DAG, RetAddrFrIdx, Chain, IsTailCall, Is64Bit,
                                  FPDiff, dl);

  SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPass;
  SmallVector<SDValue, 8> MemOpChains;
  SDValue StackPtr;

  // Walk the register/memloc assignments, inserting copies/loads.  In the case
  // of tail call optimization arguments are handle later.
  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    CCValAssign &VA = ArgLocs[i];
    MVT RegVT = VA.getLocVT();
    SDValue Arg = TheCall->getArg(i);
    ISD::ArgFlagsTy Flags = TheCall->getArgFlags(i);
    bool isByVal = Flags.isByVal();

    // Promote the value if needed.
    switch (VA.getLocInfo()) {
    default: llvm_unreachable("Unknown loc info!");
    case CCValAssign::Full: break;
    case CCValAssign::SExt:
      Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, RegVT, Arg);
      break;
    case CCValAssign::ZExt:
      Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, RegVT, Arg);
      break;
    case CCValAssign::AExt:
      if (RegVT.isVector() && RegVT.getSizeInBits() == 128) {
        // Special case: passing MMX values in XMM registers.
        Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, Arg);
        Arg = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2i64, Arg);
        Arg = getMOVL(DAG, dl, MVT::v2i64, DAG.getUNDEF(MVT::v2i64), Arg);
      } else
        Arg = DAG.getNode(ISD::ANY_EXTEND, dl, RegVT, Arg);
      break;
    case CCValAssign::BCvt:
      Arg = DAG.getNode(ISD::BIT_CONVERT, dl, RegVT, Arg);
      break;
    case CCValAssign::Indirect: {
      // Store the argument.
      SDValue SpillSlot = DAG.CreateStackTemporary(VA.getValVT());
      int FI = cast<FrameIndexSDNode>(SpillSlot)->getIndex();
      Chain = DAG.getStore(Chain, dl, Arg, SpillSlot,
                           PseudoSourceValue::getFixedStack(FI), 0);
      Arg = SpillSlot;
      break;
    }
    }

    if (VA.isRegLoc()) {
      RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
    } else {
      if (!IsTailCall || (IsTailCall && isByVal)) {
        assert(VA.isMemLoc());
        if (StackPtr.getNode() == 0)
          StackPtr = DAG.getCopyFromReg(Chain, dl, X86StackPtr, getPointerTy());

        MemOpChains.push_back(LowerMemOpCallTo(TheCall, DAG, StackPtr, VA,
                                               Chain, Arg, Flags));
      }
    }
  }

  if (!MemOpChains.empty())
    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                        &MemOpChains[0], MemOpChains.size());

  // Build a sequence of copy-to-reg nodes chained together with token chain
  // and flag operands which copy the outgoing args into registers.
  SDValue InFlag;
  // Tail call byval lowering might overwrite argument registers so in case of
  // tail call optimization the copies to registers are lowered later.
  if (!IsTailCall)
    for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
      Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
                               RegsToPass[i].second, InFlag);
      InFlag = Chain.getValue(1);
    }

  
  if (Subtarget->isPICStyleGOT()) {
    // ELF / PIC requires GOT in the EBX register before function calls via PLT
    // GOT pointer.
    if (!IsTailCall) {
      Chain = DAG.getCopyToReg(Chain, dl, X86::EBX,
                               DAG.getNode(X86ISD::GlobalBaseReg,
                                           DebugLoc::getUnknownLoc(),
                                           getPointerTy()),
                               InFlag);
      InFlag = Chain.getValue(1);
    } else {
      // If we are tail calling and generating PIC/GOT style code load the
      // address of the callee into ECX. The value in ecx is used as target of
      // the tail jump. This is done to circumvent the ebx/callee-saved problem
      // for tail calls on PIC/GOT architectures. Normally we would just put the
      // address of GOT into ebx and then call target@PLT. But for tail calls
      // ebx would be restored (since ebx is callee saved) before jumping to the
      // target@PLT.

      // Note: The actual moving to ECX is done further down.
      GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
      if (G && !G->getGlobal()->hasHiddenVisibility() &&
          !G->getGlobal()->hasProtectedVisibility())
        Callee = LowerGlobalAddress(Callee, DAG);
      else if (isa<ExternalSymbolSDNode>(Callee))
        Callee = LowerExternalSymbol(Callee, DAG);
    }
  }

  if (Is64Bit && isVarArg) {
    // From AMD64 ABI document:
    // For calls that may call functions that use varargs or stdargs
    // (prototype-less calls or calls to functions containing ellipsis (...) in
    // the declaration) %al is used as hidden argument to specify the number
    // of SSE registers used. The contents of %al do not need to match exactly
    // the number of registers, but must be an ubound on the number of SSE
    // registers used and is in the range 0 - 8 inclusive.

    // FIXME: Verify this on Win64
    // Count the number of XMM registers allocated.
    static const unsigned XMMArgRegs[] = {
      X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
      X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7
    };
    unsigned NumXMMRegs = CCInfo.getFirstUnallocated(XMMArgRegs, 8);
    assert((Subtarget->hasSSE1() || !NumXMMRegs)
           && "SSE registers cannot be used when SSE is disabled");

    Chain = DAG.getCopyToReg(Chain, dl, X86::AL,
                             DAG.getConstant(NumXMMRegs, MVT::i8), InFlag);
    InFlag = Chain.getValue(1);
  }


  // For tail calls lower the arguments to the 'real' stack slot.
  if (IsTailCall) {
    SmallVector<SDValue, 8> MemOpChains2;
    SDValue FIN;
    int FI = 0;
    // Do not flag preceeding copytoreg stuff together with the following stuff.
    InFlag = SDValue();
    for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
      CCValAssign &VA = ArgLocs[i];
      if (!VA.isRegLoc()) {
        assert(VA.isMemLoc());
        SDValue Arg = TheCall->getArg(i);
        ISD::ArgFlagsTy Flags = TheCall->getArgFlags(i);
        // Create frame index.
        int32_t Offset = VA.getLocMemOffset()+FPDiff;
        uint32_t OpSize = (VA.getLocVT().getSizeInBits()+7)/8;
        FI = MF.getFrameInfo()->CreateFixedObject(OpSize, Offset);
        FIN = DAG.getFrameIndex(FI, getPointerTy());

        if (Flags.isByVal()) {
          // Copy relative to framepointer.
          SDValue Source = DAG.getIntPtrConstant(VA.getLocMemOffset());
          if (StackPtr.getNode() == 0)
            StackPtr = DAG.getCopyFromReg(Chain, dl, X86StackPtr,
                                          getPointerTy());
          Source = DAG.getNode(ISD::ADD, dl, getPointerTy(), StackPtr, Source);

          MemOpChains2.push_back(CreateCopyOfByValArgument(Source, FIN, Chain,
                                                           Flags, DAG, dl));
        } else {
          // Store relative to framepointer.
          MemOpChains2.push_back(
            DAG.getStore(Chain, dl, Arg, FIN,
                         PseudoSourceValue::getFixedStack(FI), 0));
        }
      }
    }

    if (!MemOpChains2.empty())
      Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                          &MemOpChains2[0], MemOpChains2.size());

    // Copy arguments to their registers.
    for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
      Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
                               RegsToPass[i].second, InFlag);
      InFlag = Chain.getValue(1);
    }
    InFlag =SDValue();

    // Store the return address to the appropriate stack slot.
    Chain = EmitTailCallStoreRetAddr(DAG, MF, Chain, RetAddrFrIdx, Is64Bit,
                                     FPDiff, dl);
  }

  // If the callee is a GlobalAddress node (quite common, every direct call is)
  // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
    // We should use extra load for direct calls to dllimported functions in
    // non-JIT mode.
    GlobalValue *GV = G->getGlobal();
    if (!GV->hasDLLImportLinkage()) {
      unsigned char OpFlags = 0;
    
      // On ELF targets, in both X86-64 and X86-32 mode, direct calls to
      // external symbols most go through the PLT in PIC mode.  If the symbol
      // has hidden or protected visibility, or if it is static or local, then
      // we don't need to use the PLT - we can directly call it.
      if (Subtarget->isTargetELF() &&
          getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
          GV->hasDefaultVisibility() && !GV->hasLocalLinkage()) {
        OpFlags = X86II::MO_PLT;
      } else if (Subtarget->isPICStyleStubAny() &&
               (GV->isDeclaration() || GV->isWeakForLinker()) &&
               Subtarget->getDarwinVers() < 9) {
        // PC-relative references to external symbols should go through $stub,
        // unless we're building with the leopard linker or later, which
        // automatically synthesizes these stubs.
        OpFlags = X86II::MO_DARWIN_STUB;
      }

      Callee = DAG.getTargetGlobalAddress(GV, getPointerTy(),
                                          G->getOffset(), OpFlags);
    }
  } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
    unsigned char OpFlags = 0;

    // On ELF targets, in either X86-64 or X86-32 mode, direct calls to external
    // symbols should go through the PLT.
    if (Subtarget->isTargetELF() &&
        getTargetMachine().getRelocationModel() == Reloc::PIC_) {
      OpFlags = X86II::MO_PLT;
    } else if (Subtarget->isPICStyleStubAny() &&
             Subtarget->getDarwinVers() < 9) {
      // PC-relative references to external symbols should go through $stub,
      // unless we're building with the leopard linker or later, which
      // automatically synthesizes these stubs.
      OpFlags = X86II::MO_DARWIN_STUB;
    }
      
    Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy(),
                                         OpFlags);
  } else if (IsTailCall) {
    unsigned Opc = Is64Bit ? X86::R11 : X86::EAX;

    Chain = DAG.getCopyToReg(Chain,  dl,
                             DAG.getRegister(Opc, getPointerTy()),
                             Callee,InFlag);
    Callee = DAG.getRegister(Opc, getPointerTy());
    // Add register as live out.
    MF.getRegInfo().addLiveOut(Opc);
  }

  // Returns a chain & a flag for retval copy to use.
  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
  SmallVector<SDValue, 8> Ops;

  if (IsTailCall) {
    Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true),
                           DAG.getIntPtrConstant(0, true), InFlag);
    InFlag = Chain.getValue(1);

    // Returns a chain & a flag for retval copy to use.
    NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
    Ops.clear();
  }

  Ops.push_back(Chain);
  Ops.push_back(Callee);

  if (IsTailCall)
    Ops.push_back(DAG.getConstant(FPDiff, MVT::i32));

  // Add argument registers to the end of the list so that they are known live
  // into the call.
  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
    Ops.push_back(DAG.getRegister(RegsToPass[i].first,
                                  RegsToPass[i].second.getValueType()));

  // Add an implicit use GOT pointer in EBX.
  if (!IsTailCall && Subtarget->isPICStyleGOT())
    Ops.push_back(DAG.getRegister(X86::EBX, getPointerTy()));

  // Add an implicit use of AL for x86 vararg functions.
  if (Is64Bit && isVarArg)
    Ops.push_back(DAG.getRegister(X86::AL, MVT::i8));

  if (InFlag.getNode())
    Ops.push_back(InFlag);

  if (IsTailCall) {
    assert(InFlag.getNode() &&
           "Flag must be set. Depend on flag being set in LowerRET");
    Chain = DAG.getNode(X86ISD::TAILCALL, dl,
                        TheCall->getVTList(), &Ops[0], Ops.size());

    return SDValue(Chain.getNode(), Op.getResNo());
  }

  Chain = DAG.getNode(X86ISD::CALL, dl, NodeTys, &Ops[0], Ops.size());
  InFlag = Chain.getValue(1);

  // Create the CALLSEQ_END node.
  unsigned NumBytesForCalleeToPush;
  if (IsCalleePop(isVarArg, CC))
    NumBytesForCalleeToPush = NumBytes;    // Callee pops everything
  else if (!Is64Bit && CC != CallingConv::Fast && IsStructRet)
    // If this is is a call to a struct-return function, the callee
    // pops the hidden struct pointer, so we have to push it back.
    // This is common for Darwin/X86, Linux & Mingw32 targets.
    NumBytesForCalleeToPush = 4;
  else
    NumBytesForCalleeToPush = 0;  // Callee pops nothing.

  // Returns a flag for retval copy to use.
  Chain = DAG.getCALLSEQ_END(Chain,
                             DAG.getIntPtrConstant(NumBytes, true),
                             DAG.getIntPtrConstant(NumBytesForCalleeToPush,
                                                   true),
                             InFlag);
  InFlag = Chain.getValue(1);

  // Handle result values, copying them out of physregs into vregs that we
  // return.
  return SDValue(LowerCallResult(Chain, InFlag, TheCall, CC, DAG),
                 Op.getResNo());
}


//===----------------------------------------------------------------------===//
//                Fast Calling Convention (tail call) implementation
//===----------------------------------------------------------------------===//

//  Like std call, callee cleans arguments, convention except that ECX is
//  reserved for storing the tail called function address. Only 2 registers are
//  free for argument passing (inreg). Tail call optimization is performed
//  provided:
//                * tailcallopt is enabled
//                * caller/callee are fastcc
//  On X86_64 architecture with GOT-style position independent code only local
//  (within module) calls are supported at the moment.
//  To keep the stack aligned according to platform abi the function
//  GetAlignedArgumentStackSize ensures that argument delta is always multiples
//  of stack alignment. (Dynamic linkers need this - darwin's dyld for example)
//  If a tail called function callee has more arguments than the caller the
//  caller needs to make sure that there is room to move the RETADDR to. This is
//  achieved by reserving an area the size of the argument delta right after the
//  original REtADDR, but before the saved framepointer or the spilled registers
//  e.g. caller(arg1, arg2) calls callee(arg1, arg2,arg3,arg4)
//  stack layout:
//    arg1
//    arg2
//    RETADDR
//    [ new RETADDR
//      move area ]
//    (possible EBP)
//    ESI
//    EDI
//    local1 ..

/// GetAlignedArgumentStackSize - Make the stack size align e.g 16n + 12 aligned
/// for a 16 byte align requirement.
unsigned X86TargetLowering::GetAlignedArgumentStackSize(unsigned StackSize,
                                                        SelectionDAG& DAG) {
  MachineFunction &MF = DAG.getMachineFunction();
  const TargetMachine &TM = MF.getTarget();
  const TargetFrameInfo &TFI = *TM.getFrameInfo();
  unsigned StackAlignment = TFI.getStackAlignment();
  uint64_t AlignMask = StackAlignment - 1;
  int64_t Offset = StackSize;
  uint64_t SlotSize = TD->getPointerSize();
  if ( (Offset & AlignMask) <= (StackAlignment - SlotSize) ) {
    // Number smaller than 12 so just add the difference.
    Offset += ((StackAlignment - SlotSize) - (Offset & AlignMask));
  } else {
    // Mask out lower bits, add stackalignment once plus the 12 bytes.
    Offset = ((~AlignMask) & Offset) + StackAlignment +
      (StackAlignment-SlotSize);
  }
  return Offset;
}

/// IsEligibleForTailCallElimination - Check to see whether the next instruction
/// following the call is a return. A function is eligible if caller/callee
/// calling conventions match, currently only fastcc supports tail calls, and
/// the function CALL is immediatly followed by a RET.
bool X86TargetLowering::IsEligibleForTailCallOptimization(CallSDNode *TheCall,
                                                      SDValue Ret,
                                                      SelectionDAG& DAG) const {
  if (!PerformTailCallOpt)
    return false;

  if (CheckTailCallReturnConstraints(TheCall, Ret)) {
    unsigned CallerCC =
      DAG.getMachineFunction().getFunction()->getCallingConv();
    unsigned CalleeCC = TheCall->getCallingConv();
    if (CalleeCC == CallingConv::Fast && CallerCC == CalleeCC)
      return true;
  }

  return false;
}

FastISel *
X86TargetLowering::createFastISel(MachineFunction &mf,
                                  MachineModuleInfo *mmo,
                                  DwarfWriter *dw,
                                  DenseMap<const Value *, unsigned> &vm,
                                  DenseMap<const BasicBlock *,
                                           MachineBasicBlock *> &bm,
                                  DenseMap<const AllocaInst *, int> &am
#ifndef NDEBUG
                                  , SmallSet<Instruction*, 8> &cil
#endif
                                  ) {
  return X86::createFastISel(mf, mmo, dw, vm, bm, am
#ifndef NDEBUG
                             , cil
#endif
                             );
}


//===----------------------------------------------------------------------===//
//                           Other Lowering Hooks
//===----------------------------------------------------------------------===//


SDValue X86TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) {
  MachineFunction &MF = DAG.getMachineFunction();
  X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
  int ReturnAddrIndex = FuncInfo->getRAIndex();

  if (ReturnAddrIndex == 0) {
    // Set up a frame object for the return address.
    uint64_t SlotSize = TD->getPointerSize();
    ReturnAddrIndex = MF.getFrameInfo()->CreateFixedObject(SlotSize, -SlotSize);
    FuncInfo->setRAIndex(ReturnAddrIndex);
  }

  return DAG.getFrameIndex(ReturnAddrIndex, getPointerTy());
}


/// TranslateX86CC - do a one to one translation of a ISD::CondCode to the X86
/// specific condition code, returning the condition code and the LHS/RHS of the
/// comparison to make.
static unsigned TranslateX86CC(ISD::CondCode SetCCOpcode, bool isFP,
                               SDValue &LHS, SDValue &RHS, SelectionDAG &DAG) {
  if (!isFP) {
    if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS)) {
      if (SetCCOpcode == ISD::SETGT && RHSC->isAllOnesValue()) {
        // X > -1   -> X == 0, jump !sign.
        RHS = DAG.getConstant(0, RHS.getValueType());
        return X86::COND_NS;
      } else if (SetCCOpcode == ISD::SETLT && RHSC->isNullValue()) {
        // X < 0   -> X == 0, jump on sign.
        return X86::COND_S;
      } else if (SetCCOpcode == ISD::SETLT && RHSC->getZExtValue() == 1) {
        // X < 1   -> X <= 0
        RHS = DAG.getConstant(0, RHS.getValueType());
        return X86::COND_LE;
      }
    }

    switch (SetCCOpcode) {
    default: llvm_unreachable("Invalid integer condition!");
    case ISD::SETEQ:  return X86::COND_E;
    case ISD::SETGT:  return X86::COND_G;
    case ISD::SETGE:  return X86::COND_GE;
    case ISD::SETLT:  return X86::COND_L;
    case ISD::SETLE:  return X86::COND_LE;
    case ISD::SETNE:  return X86::COND_NE;
    case ISD::SETULT: return X86::COND_B;
    case ISD::SETUGT: return X86::COND_A;
    case ISD::SETULE: return X86::COND_BE;
    case ISD::SETUGE: return X86::COND_AE;
    }
  }

  // First determine if it is required or is profitable to flip the operands.

  // If LHS is a foldable load, but RHS is not, flip the condition.
  if ((ISD::isNON_EXTLoad(LHS.getNode()) && LHS.hasOneUse()) &&
      !(ISD::isNON_EXTLoad(RHS.getNode()) && RHS.hasOneUse())) {
    SetCCOpcode = getSetCCSwappedOperands(SetCCOpcode);
    std::swap(LHS, RHS);
  }

  switch (SetCCOpcode) {
  default: break;
  case ISD::SETOLT:
  case ISD::SETOLE:
  case ISD::SETUGT:
  case ISD::SETUGE:
    std::swap(LHS, RHS);
    break;
  }

  // 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: llvm_unreachable("Condcode should be pre-legalized away");
  case ISD::SETUEQ:
  case ISD::SETEQ:   return X86::COND_E;
  case ISD::SETOLT:              // flipped
  case ISD::SETOGT:
  case ISD::SETGT:   return X86::COND_A;
  case ISD::SETOLE:              // flipped
  case ISD::SETOGE:
  case ISD::SETGE:   return X86::COND_AE;
  case ISD::SETUGT:              // flipped
  case ISD::SETULT:
  case ISD::SETLT:   return X86::COND_B;
  case ISD::SETUGE:              // flipped
  case ISD::SETULE:
  case ISD::SETLE:   return X86::COND_BE;
  case ISD::SETONE:
  case ISD::SETNE:   return X86::COND_NE;
  case ISD::SETUO:   return X86::COND_P;
  case ISD::SETO:    return X86::COND_NP;
  }
}

/// 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 X86::COND_B:
  case X86::COND_BE:
  case X86::COND_E:
  case X86::COND_P:
  case X86::COND_A:
  case X86::COND_AE:
  case X86::COND_NE:
  case X86::COND_NP:
    return true;
  }
}

/// isUndefOrInRange - Return true if Val is undef or if its value falls within
/// the specified range (L, H].
static bool isUndefOrInRange(int Val, int Low, int Hi) {
  return (Val < 0) || (Val >= Low && Val < Hi);
}

/// isUndefOrEqual - Val is either less than zero (undef) or equal to the
/// specified value.
static bool isUndefOrEqual(int Val, int CmpVal) {
  if (Val < 0 || Val == CmpVal)
    return true;
  return false;
}

/// isPSHUFDMask - Return true if the node specifies a shuffle of elements that
/// is suitable for input to PSHUFD or PSHUFW.  That is, it doesn't reference
/// the second operand.
static bool isPSHUFDMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  if (VT == MVT::v4f32 || VT == MVT::v4i32 || VT == MVT::v4i16)
    return (Mask[0] < 4 && Mask[1] < 4 && Mask[2] < 4 && Mask[3] < 4);
  if (VT == MVT::v2f64 || VT == MVT::v2i64)
    return (Mask[0] < 2 && Mask[1] < 2);
  return false;
}

bool X86::isPSHUFDMask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M; 
  N->getMask(M);
  return ::isPSHUFDMask(M, N->getValueType(0));
}

/// isPSHUFHWMask - Return true if the node specifies a shuffle of elements that
/// is suitable for input to PSHUFHW.
static bool isPSHUFHWMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  if (VT != MVT::v8i16)
    return false;
  
  // Lower quadword copied in order or undef.
  for (int i = 0; i != 4; ++i)
    if (Mask[i] >= 0 && Mask[i] != i)
      return false;
  
  // Upper quadword shuffled.
  for (int i = 4; i != 8; ++i)
    if (Mask[i] >= 0 && (Mask[i] < 4 || Mask[i] > 7))
      return false;
  
  return true;
}

bool X86::isPSHUFHWMask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M; 
  N->getMask(M);
  return ::isPSHUFHWMask(M, N->getValueType(0));
}

/// isPSHUFLWMask - Return true if the node specifies a shuffle of elements that
/// is suitable for input to PSHUFLW.
static bool isPSHUFLWMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  if (VT != MVT::v8i16)
    return false;
  
  // Upper quadword copied in order.
  for (int i = 4; i != 8; ++i)
    if (Mask[i] >= 0 && Mask[i] != i)
      return false;
  
  // Lower quadword shuffled.
  for (int i = 0; i != 4; ++i)
    if (Mask[i] >= 4)
      return false;
  
  return true;
}

bool X86::isPSHUFLWMask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M; 
  N->getMask(M);
  return ::isPSHUFLWMask(M, N->getValueType(0));
}

/// isSHUFPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to SHUFP*.
static bool isSHUFPMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  int NumElems = VT.getVectorNumElements();
  if (NumElems != 2 && NumElems != 4)
    return false;
  
  int Half = NumElems / 2;
  for (int i = 0; i < Half; ++i)
    if (!isUndefOrInRange(Mask[i], 0, NumElems))
      return false;
  for (int i = Half; i < NumElems; ++i)
    if (!isUndefOrInRange(Mask[i], NumElems, NumElems*2))
      return false;
  
  return true;
}

bool X86::isSHUFPMask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isSHUFPMask(M, N->getValueType(0));
}

/// isCommutedSHUFP - Returns true if the shuffle mask is exactly
/// the reverse of what x86 shuffles want. x86 shuffles requires the lower
/// half elements to come from vector 1 (which would equal the dest.) and
/// the upper half to come from vector 2.
static bool isCommutedSHUFPMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  int NumElems = VT.getVectorNumElements();
  
  if (NumElems != 2 && NumElems != 4) 
    return false;
  
  int Half = NumElems / 2;
  for (int i = 0; i < Half; ++i)
    if (!isUndefOrInRange(Mask[i], NumElems, NumElems*2))
      return false;
  for (int i = Half; i < NumElems; ++i)
    if (!isUndefOrInRange(Mask[i], 0, NumElems))
      return false;
  return true;
}

static bool isCommutedSHUFP(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return isCommutedSHUFPMask(M, N->getValueType(0));
}

/// isMOVHLPSMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVHLPS.
bool X86::isMOVHLPSMask(ShuffleVectorSDNode *N) {
  if (N->getValueType(0).getVectorNumElements() != 4)
    return false;

  // Expect bit0 == 6, bit1 == 7, bit2 == 2, bit3 == 3
  return isUndefOrEqual(N->getMaskElt(0), 6) &&
         isUndefOrEqual(N->getMaskElt(1), 7) &&
         isUndefOrEqual(N->getMaskElt(2), 2) &&
         isUndefOrEqual(N->getMaskElt(3), 3);
}

/// isMOVLPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVLP{S|D}.
bool X86::isMOVLPMask(ShuffleVectorSDNode *N) {
  unsigned NumElems = N->getValueType(0).getVectorNumElements();

  if (NumElems != 2 && NumElems != 4)
    return false;

  for (unsigned i = 0; i < NumElems/2; ++i)
    if (!isUndefOrEqual(N->getMaskElt(i), i + NumElems))
      return false;

  for (unsigned i = NumElems/2; i < NumElems; ++i)
    if (!isUndefOrEqual(N->getMaskElt(i), i))
      return false;

  return true;
}

/// isMOVHPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVHP{S|D}
/// and MOVLHPS.
bool X86::isMOVHPMask(ShuffleVectorSDNode *N) {
  unsigned NumElems = N->getValueType(0).getVectorNumElements();

  if (NumElems != 2 && NumElems != 4)
    return false;

  for (unsigned i = 0; i < NumElems/2; ++i)
    if (!isUndefOrEqual(N->getMaskElt(i), i))
      return false;

  for (unsigned i = 0; i < NumElems/2; ++i)
    if (!isUndefOrEqual(N->getMaskElt(i + NumElems/2), i + NumElems))
      return false;

  return true;
}

/// isMOVHLPS_v_undef_Mask - Special case of isMOVHLPSMask for canonical form
/// of vector_shuffle v, v, <2, 3, 2, 3>, i.e. vector_shuffle v, undef,
/// <2, 3, 2, 3>
bool X86::isMOVHLPS_v_undef_Mask(ShuffleVectorSDNode *N) {
  unsigned NumElems = N->getValueType(0).getVectorNumElements();
  
  if (NumElems != 4)
    return false;
  
  return isUndefOrEqual(N->getMaskElt(0), 2) && 
         isUndefOrEqual(N->getMaskElt(1), 3) &&
         isUndefOrEqual(N->getMaskElt(2), 2) && 
         isUndefOrEqual(N->getMaskElt(3), 3);
}

/// isUNPCKLMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to UNPCKL.
static bool isUNPCKLMask(const SmallVectorImpl<int> &Mask, MVT VT,
                         bool V2IsSplat = false) {
  int NumElts = VT.getVectorNumElements();
  if (NumElts != 2 && NumElts != 4 && NumElts != 8 && NumElts != 16)
    return false;
  
  for (int i = 0, j = 0; i != NumElts; i += 2, ++j) {
    int BitI  = Mask[i];
    int BitI1 = Mask[i+1];
    if (!isUndefOrEqual(BitI, j))
      return false;
    if (V2IsSplat) {
      if (!isUndefOrEqual(BitI1, NumElts))
        return false;
    } else {
      if (!isUndefOrEqual(BitI1, j + NumElts))
        return false;
    }
  }
  return true;
}

bool X86::isUNPCKLMask(ShuffleVectorSDNode *N, bool V2IsSplat) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isUNPCKLMask(M, N->getValueType(0), V2IsSplat);
}

/// isUNPCKHMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to UNPCKH.
static bool isUNPCKHMask(const SmallVectorImpl<int> &Mask, MVT VT, 
                         bool V2IsSplat = false) {
  int NumElts = VT.getVectorNumElements();
  if (NumElts != 2 && NumElts != 4 && NumElts != 8 && NumElts != 16)
    return false;
  
  for (int i = 0, j = 0; i != NumElts; i += 2, ++j) {
    int BitI  = Mask[i];
    int BitI1 = Mask[i+1];
    if (!isUndefOrEqual(BitI, j + NumElts/2))
      return false;
    if (V2IsSplat) {
      if (isUndefOrEqual(BitI1, NumElts))
        return false;
    } else {
      if (!isUndefOrEqual(BitI1, j + NumElts/2 + NumElts))
        return false;
    }
  }
  return true;
}

bool X86::isUNPCKHMask(ShuffleVectorSDNode *N, bool V2IsSplat) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isUNPCKHMask(M, N->getValueType(0), V2IsSplat);
}

/// isUNPCKL_v_undef_Mask - Special case of isUNPCKLMask for canonical form
/// of vector_shuffle v, v, <0, 4, 1, 5>, i.e. vector_shuffle v, undef,
/// <0, 0, 1, 1>
static bool isUNPCKL_v_undef_Mask(const SmallVectorImpl<int> &Mask, MVT VT) {
  int NumElems = VT.getVectorNumElements();
  if (NumElems != 2 && NumElems != 4 && NumElems != 8 && NumElems != 16)
    return false;
  
  for (int i = 0, j = 0; i != NumElems; i += 2, ++j) {
    int BitI  = Mask[i];
    int BitI1 = Mask[i+1];
    if (!isUndefOrEqual(BitI, j))
      return false;
    if (!isUndefOrEqual(BitI1, j))
      return false;
  }
  return true;
}

bool X86::isUNPCKL_v_undef_Mask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isUNPCKL_v_undef_Mask(M, N->getValueType(0));
}

/// isUNPCKH_v_undef_Mask - Special case of isUNPCKHMask for canonical form
/// of vector_shuffle v, v, <2, 6, 3, 7>, i.e. vector_shuffle v, undef,
/// <2, 2, 3, 3>
static bool isUNPCKH_v_undef_Mask(const SmallVectorImpl<int> &Mask, MVT VT) {
  int NumElems = VT.getVectorNumElements();
  if (NumElems != 2 && NumElems != 4 && NumElems != 8 && NumElems != 16)
    return false;
  
  for (int i = 0, j = NumElems / 2; i != NumElems; i += 2, ++j) {
    int BitI  = Mask[i];
    int BitI1 = Mask[i+1];
    if (!isUndefOrEqual(BitI, j))
      return false;
    if (!isUndefOrEqual(BitI1, j))
      return false;
  }
  return true;
}

bool X86::isUNPCKH_v_undef_Mask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isUNPCKH_v_undef_Mask(M, N->getValueType(0));
}

/// isMOVLMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVSS,
/// MOVSD, and MOVD, i.e. setting the lowest element.
static bool isMOVLMask(const SmallVectorImpl<int> &Mask, MVT VT) {
  if (VT.getVectorElementType().getSizeInBits() < 32)
    return false;

  int NumElts = VT.getVectorNumElements();
  
  if (!isUndefOrEqual(Mask[0], NumElts))
    return false;
  
  for (int i = 1; i < NumElts; ++i)
    if (!isUndefOrEqual(Mask[i], i))
      return false;
  
  return true;
}

bool X86::isMOVLMask(ShuffleVectorSDNode *N) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return ::isMOVLMask(M, N->getValueType(0));
}

/// isCommutedMOVL - Returns true if the shuffle mask is except the reverse
/// of what x86 movss want. X86 movs requires the lowest  element to be lowest
/// element of vector 2 and the other elements to come from vector 1 in order.
static bool isCommutedMOVLMask(const SmallVectorImpl<int> &Mask, MVT VT,
                               bool V2IsSplat = false, bool V2IsUndef = false) {
  int NumOps = VT.getVectorNumElements();
  if (NumOps != 2 && NumOps != 4 && NumOps != 8 && NumOps != 16)
    return false;
  
  if (!isUndefOrEqual(Mask[0], 0))
    return false;
  
  for (int i = 1; i < NumOps; ++i)
    if (!(isUndefOrEqual(Mask[i], i+NumOps) ||
          (V2IsUndef && isUndefOrInRange(Mask[i], NumOps, NumOps*2)) ||
          (V2IsSplat && isUndefOrEqual(Mask[i], NumOps))))
      return false;
  
  return true;
}

static bool isCommutedMOVL(ShuffleVectorSDNode *N, bool V2IsSplat = false,
                           bool V2IsUndef = false) {
  SmallVector<int, 8> M;
  N->getMask(M);
  return isCommutedMOVLMask(M, N->getValueType(0), V2IsSplat, V2IsUndef);
}

/// isMOVSHDUPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVSHDUP.
bool X86::isMOVSHDUPMask(ShuffleVectorSDNode *N) {
  if (N->getValueType(0).getVectorNumElements() != 4)
    return false;

  // Expect 1, 1, 3, 3
  for (unsigned i = 0; i < 2; ++i) {
    int Elt = N->getMaskElt(i);
    if (Elt >= 0 && Elt != 1)
      return false;
  }

  bool HasHi = false;
  for (unsigned i = 2; i < 4; ++i) {
    int Elt = N->getMaskElt(i);
    if (Elt >= 0 && Elt != 3)
      return false;
    if (Elt == 3)
      HasHi = true;
  }
  // Don't use movshdup if it can be done with a shufps.
  // FIXME: verify that matching u, u, 3, 3 is what we want.
  return HasHi;
}

/// isMOVSLDUPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVSLDUP.
bool X86::isMOVSLDUPMask(ShuffleVectorSDNode *N) {
  if (N->getValueType(0).getVectorNumElements() != 4)
    return false;

  // Expect 0, 0, 2, 2
  for (unsigned i = 0; i < 2; ++i)
    if (N->getMaskElt(i) > 0)
      return false;

  bool HasHi = false;
  for (unsigned i = 2; i < 4; ++i) {
    int Elt = N->getMaskElt(i);
    if (Elt >= 0 && Elt != 2)
      return false;
    if (Elt == 2)
      HasHi = true;
  }
  // Don't use movsldup if it can be done with a shufps.
  return HasHi;
}

/// isMOVDDUPMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a shuffle of elements that is suitable for input to MOVDDUP.
bool X86::isMOVDDUPMask(ShuffleVectorSDNode *N) {
  int e = N->getValueType(0).getVectorNumElements() / 2;
  
  for (int i = 0; i < e; ++i)
    if (!isUndefOrEqual(N->getMaskElt(i), i))
      return false;
  for (int i = 0; i < e; ++i)
    if (!isUndefOrEqual(N->getMaskElt(e+i), i))
      return false;
  return true;
}

/// getShuffleSHUFImmediate - Return the appropriate immediate to shuffle
/// the specified isShuffleMask VECTOR_SHUFFLE mask with PSHUF* and SHUFP*
/// instructions.
unsigned X86::getShuffleSHUFImmediate(SDNode *N) {
  ShuffleVectorSDNode *SVOp = cast<ShuffleVectorSDNode>(N);
  int NumOperands = SVOp->getValueType(0).getVectorNumElements();

  unsigned Shift = (NumOperands == 4) ? 2 : 1;
  unsigned Mask = 0;
  for (int i = 0; i < NumOperands; ++i) {
    int Val = SVOp->getMaskElt(NumOperands-i-1);
    if (Val < 0) Val = 0;
    if (Val >= NumOperands) Val -= NumOperands;
    Mask |= Val;
    if (i != NumOperands - 1)
      Mask <<= Shift;
  }
  return Mask;
}

/// getShufflePSHUFHWImmediate - Return the appropriate immediate to shuffle
/// the specified isShuffleMask VECTOR_SHUFFLE mask with PSHUFHW
/// instructions.
unsigned X86::getShufflePSHUFHWImmediate(SDNode *N) {
  ShuffleVectorSDNode *SVOp = cast<ShuffleVectorSDNode>(N);
  unsigned Mask = 0;
  // 8 nodes, but we only care about the last 4.
  for (unsigned i = 7; i >= 4; --i) {
    int Val = SVOp->getMaskElt(i);
    if (Val >= 0)
      Mask |= (Val - 4);
    if (i != 4)
      Mask <<= 2;
  }
  return Mask;
}

/// getShufflePSHUFLWImmediate - Return the appropriate immediate to shuffle
/// the specified isShuffleMask VECTOR_SHUFFLE mask with PSHUFLW
/// instructions.
unsigned X86::getShufflePSHUFLWImmediate(SDNode *N) {
  ShuffleVectorSDNode *SVOp = cast<ShuffleVectorSDNode>(N);
  unsigned Mask = 0;
  // 8 nodes, but we only care about the first 4.
  for (int i = 3; i >= 0; --i) {
    int Val = SVOp->getMaskElt(i);
    if (Val >= 0)
      Mask |= Val;
    if (i != 0)
      Mask <<= 2;
  }
  return Mask;
}

/// isZeroNode - Returns true if Elt is a constant zero or a floating point
/// constant +0.0.
bool X86::isZeroNode(SDValue Elt) {
  return ((isa<ConstantSDNode>(Elt) &&
           cast<ConstantSDNode>(Elt)->getZExtValue() == 0) ||
          (isa<ConstantFPSDNode>(Elt) &&
           cast<ConstantFPSDNode>(Elt)->getValueAPF().isPosZero()));
}

/// CommuteVectorShuffle - Swap vector_shuffle operands as well as values in
/// their permute mask.
static SDValue CommuteVectorShuffle(ShuffleVectorSDNode *SVOp,
                                    SelectionDAG &DAG) {
  MVT VT = SVOp->getValueType(0);
  unsigned NumElems = VT.getVectorNumElements();
  SmallVector<int, 8> MaskVec;
  
  for (unsigned i = 0; i != NumElems; ++i) {
    int idx = SVOp->getMaskElt(i);
    if (idx < 0)
      MaskVec.push_back(idx);
    else if (idx < (int)NumElems)
      MaskVec.push_back(idx + NumElems);
    else
      MaskVec.push_back(idx - NumElems);
  }
  return DAG.getVectorShuffle(VT, SVOp->getDebugLoc(), SVOp->getOperand(1),
                              SVOp->getOperand(0), &MaskVec[0]);
}

/// CommuteVectorShuffleMask - Change values in a shuffle permute mask assuming
/// the two vector operands have swapped position.
static void CommuteVectorShuffleMask(SmallVectorImpl<int> &Mask, MVT VT) {
  unsigned NumElems = VT.getVectorNumElements();
  for (unsigned i = 0; i != NumElems; ++i) {
    int idx = Mask[i];
    if (idx < 0)
      continue;
    else if (idx < (int)NumElems)
      Mask[i] = idx + NumElems;
    else
      Mask[i] = idx - NumElems;
  }
}

/// ShouldXformToMOVHLPS - Return true if the node should be transformed to
/// match movhlps. The lower half elements should come from upper half of
/// V1 (and in order), and the upper half elements should come from the upper
/// half of V2 (and in order).
static bool ShouldXformToMOVHLPS(ShuffleVectorSDNode *Op) {
  if (Op->getValueType(0).getVectorNumElements() != 4)
    return false;
  for (unsigned i = 0, e = 2; i != e; ++i)
    if (!isUndefOrEqual(Op->getMaskElt(i), i+2))
      return false;
  for (unsigned i = 2; i != 4; ++i)
    if (!isUndefOrEqual(Op->getMaskElt(i), i+4))
      return false;
  return true;
}

/// isScalarLoadToVector - Returns true if the node is a scalar load that
/// is promoted to a vector. It also returns the LoadSDNode by reference if
/// required.
static bool isScalarLoadToVector(SDNode *N, LoadSDNode **LD = NULL) {
  if (N->getOpcode() != ISD::SCALAR_TO_VECTOR)
    return false;
  N = N->getOperand(0).getNode();
  if (!ISD::isNON_EXTLoad(N))
    return false;
  if (LD)
    *LD = cast<LoadSDNode>(N);
  return true;
}

/// ShouldXformToMOVLP{S|D} - Return true if the node should be transformed to
/// match movlp{s|d}. The lower half elements should come from lower half of
/// V1 (and in order), and the upper half elements should come from the upper
/// half of V2 (and in order). And since V1 will become the source of the
/// MOVLP, it must be either a vector load or a scalar load to vector.
static bool ShouldXformToMOVLP(SDNode *V1, SDNode *V2,
                               ShuffleVectorSDNode *Op) {
  if (!ISD::isNON_EXTLoad(V1) && !isScalarLoadToVector(V1))
    return false;
  // Is V2 is a vector load, don't do this transformation. We will try to use
  // load folding shufps op.
  if (ISD::isNON_EXTLoad(V2))
    return false;

  unsigned NumElems = Op->getValueType(0).getVectorNumElements();
  
  if (NumElems != 2 && NumElems != 4)
    return false;
  for (unsigned i = 0, e = NumElems/2; i != e; ++i)
    if (!isUndefOrEqual(Op->getMaskElt(i), i))
      return false;
  for (unsigned i = NumElems/2; i != NumElems; ++i)
    if (!isUndefOrEqual(Op->getMaskElt(i), i+NumElems))
      return false;
  return true;
}

/// isSplatVector - Returns true if N is a BUILD_VECTOR node whose elements are
/// all the same.
static bool isSplatVector(SDNode *N) {
  if (N->getOpcode() != ISD::BUILD_VECTOR)
    return false;

  SDValue SplatValue = N->getOperand(0);
  for (unsigned i = 1, e = N->getNumOperands(); i != e; ++i)
    if (N->getOperand(i) != SplatValue)
      return false;
  return true;
}

/// isZeroShuffle - Returns true if N is a VECTOR_SHUFFLE that can be resolved
/// to an zero vector. 
/// FIXME: move to dag combiner / method on ShuffleVectorSDNode
static bool isZeroShuffle(ShuffleVectorSDNode *N) {
  SDValue V1 = N->getOperand(0);
  SDValue V2 = N->getOperand(1);
  unsigned NumElems = N->getValueType(0).getVectorNumElements();
  for (unsigned i = 0; i != NumElems; ++i) {
    int Idx = N->getMaskElt(i);
    if (Idx >= (int)NumElems) {
      unsigned Opc = V2.getOpcode();
      if (Opc == ISD::UNDEF || ISD::isBuildVectorAllZeros(V2.getNode()))
        continue;
      if (Opc != ISD::BUILD_VECTOR ||
          !X86::isZeroNode(V2.getOperand(Idx-NumElems)))
        return false;
    } else if (Idx >= 0) {
      unsigned Opc = V1.getOpcode();
      if (Opc == ISD::UNDEF || ISD::isBuildVectorAllZeros(V1.getNode()))
        continue;
      if (Opc != ISD::BUILD_VECTOR ||
          !X86::isZeroNode(V1.getOperand(Idx)))
        return false;
    }
  }
  return true;
}

/// getZeroVector - Returns a vector of specified type with all zero elements.
///
static SDValue getZeroVector(MVT VT, bool HasSSE2, SelectionDAG &DAG,
                             DebugLoc dl) {
  assert(VT.isVector() && "Expected a vector type");

  // Always build zero vectors as <4 x i32> or <2 x i32> bitcasted to their dest
  // type.  This ensures they get CSE'd.
  SDValue Vec;
  if (VT.getSizeInBits() == 64) { // MMX
    SDValue Cst = DAG.getTargetConstant(0, MVT::i32);
    Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v2i32, Cst, Cst);
  } else if (HasSSE2) {  // SSE2
    SDValue Cst = DAG.getTargetConstant(0, MVT::i32);
    Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v4i32, Cst, Cst, Cst, Cst);
  } else { // SSE1
    SDValue Cst = DAG.getTargetConstantFP(+0.0, MVT::f32);
    Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v4f32, Cst, Cst, Cst, Cst);
  }
  return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vec);
}

/// getOnesVector - Returns a vector of specified type with all bits set.
///
static SDValue getOnesVector(MVT VT, SelectionDAG &DAG, DebugLoc dl) {
  assert(VT.isVector() && "Expected a vector type");

  // Always build ones vectors as <4 x i32> or <2 x i32> bitcasted to their dest
  // type.  This ensures they get CSE'd.
  SDValue Cst = DAG.getTargetConstant(~0U, MVT::i32);
  SDValue Vec;
  if (VT.getSizeInBits() == 64)  // MMX
    Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v2i32, Cst, Cst);
  else                                              // SSE
    Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v4i32, Cst, Cst, Cst, Cst);
  return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vec);
}


/// NormalizeMask - V2 is a splat, modify the mask (if needed) so all elements
/// that point to V2 points to its first element.
static SDValue NormalizeMask(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG) {
  MVT VT = SVOp->getValueType(0);
  unsigned NumElems = VT.getVectorNumElements();
  
  bool Changed = false;
  SmallVector<int, 8> MaskVec;
  SVOp->getMask(MaskVec);
  
  for (unsigned i = 0; i != NumElems; ++i) {
    if (MaskVec[i] > (int)NumElems) {
      MaskVec[i] = NumElems;
      Changed = true;
    }
  }
  if (Changed)
    return DAG.getVectorShuffle(VT, SVOp->getDebugLoc(), SVOp->getOperand(0),
                                SVOp->getOperand(1), &MaskVec[0]);
  return SDValue(SVOp, 0);
}

/// getMOVLMask - Returns a vector_shuffle mask for an movs{s|d}, movd
/// operation of specified width.
static SDValue getMOVL(SelectionDAG &DAG, DebugLoc dl, MVT VT, SDValue V1,
                       SDValue V2) {
  unsigned NumElems = VT.getVectorNumElements();
  SmallVector<int, 8> Mask;
  Mask.push_back(NumElems);
  for (unsigned i = 1; i != NumElems; ++i)
    Mask.push_back(i);
  return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask[0]);
}

/// getUnpackl - Returns a vector_shuffle node for an unpackl operation.
static SDValue getUnpackl(SelectionDAG &DAG, DebugLoc dl, MVT VT, SDValue V1,
                          SDValue V2) {
  unsigned NumElems = VT.getVectorNumElements();
  SmallVector<int, 8> Mask;
  for (unsigned i = 0, e = NumElems/2; i != e; ++i) {
    Mask.push_back(i);
    Mask.push_back(i + NumElems);
  }
  return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask[0]);
}

/// getUnpackhMask - Returns a vector_shuffle node for an unpackh operation.
static SDValue getUnpackh(SelectionDAG &DAG, DebugLoc dl, MVT VT, SDValue V1,
                          SDValue V2) {
  unsigned NumElems = VT.getVectorNumElements();
  unsigned Half = NumElems/2;
  SmallVector<int, 8> Mask;
  for (unsigned i = 0; i != Half; ++i) {
    Mask.push_back(i + Half);
    Mask.push_back(i + NumElems + Half);
  }
  return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask[0]);
}

/// PromoteSplat - Promote a splat of v4f32, v8i16 or v16i8 to v4i32.
static SDValue PromoteSplat(ShuffleVectorSDNode *SV, SelectionDAG &DAG, 
                            bool HasSSE2) {
  if (SV->getValueType(0).getVectorNumElements() <= 4)
    return SDValue(SV, 0);
  
  MVT PVT = MVT::v4f32;
  MVT VT = SV->getValueType(0);
  DebugLoc dl = SV->getDebugLoc();
  SDValue V1 = SV->getOperand(0);
  int NumElems = VT.getVectorNumElements();
  int EltNo = SV->getSplatIndex();

  // unpack elements to the correct location
  while (NumElems > 4) {
    if (EltNo < NumElems/2) {
      V1 = getUnpackl(DAG, dl, VT, V1, V1);
    } else {
      V1 = getUnpackh(DAG, dl, VT, V1, V1);
      EltNo -= NumElems/2;
    }
    NumElems >>= 1;
  }
  
  // Perform the splat.
  int SplatMask[4] = { EltNo, EltNo, EltNo, EltNo };
  V1 = DAG.getNode(ISD::BIT_CONVERT, dl, PVT, V1);
  V1 = DAG.getVectorShuffle(PVT, dl, V1, DAG.getUNDEF(PVT), &SplatMask[0]);
  return DAG.getNode(ISD::BIT_CONVERT, dl, VT, V1);
}

/// getShuffleVectorZeroOrUndef - Return a vector_shuffle of the specified
/// vector of zero or undef vector.  This produces a shuffle where the low
/// element of V2 is swizzled into the zero/undef vector, landing at element
/// Idx.  This produces a shuffle mask like 4,1,2,3 (idx=0) or  0,1,2,4 (idx=3).
static SDValue getShuffleVectorZeroOrUndef(SDValue V2, unsigned Idx,
                                             bool isZero, bool HasSSE2,
                                             SelectionDAG &DAG) {
  MVT VT = V2.getValueType();
  SDValue V1 = isZero
    ? getZeroVector(VT, HasSSE2, DAG, V2.getDebugLoc()) : DAG.getUNDEF(VT);
  unsigned NumElems = VT.getVectorNumElements();
  SmallVector<int, 16> MaskVec;
  for (unsigned i = 0; i != NumElems; ++i)
    // If this is the insertion idx, put the low elt of V2 here.
    MaskVec.push_back(i == Idx ? NumElems : i);
  return DAG.getVectorShuffle(VT, V2.getDebugLoc(), V1, V2, &MaskVec[0]);
}

/// getNumOfConsecutiveZeros - Return the number of elements in a result of
/// a shuffle that is zero.
static
unsigned getNumOfConsecutiveZeros(ShuffleVectorSDNode *SVOp, int NumElems,
                                  bool Low, SelectionDAG &DAG) {
  unsigned NumZeros = 0;
  for (int i = 0; i < NumElems; ++i) {
    unsigned Index = Low ? i : NumElems-i-1;
    int Idx = SVOp->getMaskElt(Index);
    if (Idx < 0) {
      ++NumZeros;
      continue;
    }
    SDValue Elt = DAG.getShuffleScalarElt(SVOp, Index);
    if (Elt.getNode() && X86::isZeroNode(Elt))
      ++NumZeros;
    else
      break;
  }
  return NumZeros;
}

/// isVectorShift - Returns true if the shuffle can be implemented as a
/// logical left or right shift of a vector.
/// FIXME: split into pslldqi, psrldqi, palignr variants.
static bool isVectorShift(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG,
                          bool &isLeft, SDValue &ShVal, unsigned &ShAmt) {
  int NumElems = SVOp->getValueType(0).getVectorNumElements();

  isLeft = true;
  unsigned NumZeros = getNumOfConsecutiveZeros(SVOp, NumElems, true, DAG);
  if (!NumZeros) {
    isLeft = false;
    NumZeros = getNumOfConsecutiveZeros(SVOp, NumElems, false, DAG);
    if (!NumZeros)
      return false;
  }
  bool SeenV1 = false;
  bool SeenV2 = false;
  for (int i = NumZeros; i < NumElems; ++i) {
    int Val = isLeft ? (i - NumZeros) : i;
    int Idx = SVOp->getMaskElt(isLeft ? i : (i - NumZeros));
    if (Idx < 0)
      continue;
    if (Idx < NumElems)
      SeenV1 = true;
    else {
      Idx -= NumElems;
      SeenV2 = true;
    }
    if (Idx != Val)
      return false;
  }
  if (SeenV1 && SeenV2)
    return false;

  ShVal = SeenV1 ? SVOp->getOperand(0) : SVOp->getOperand(1);
  ShAmt = NumZeros;
  return true;
}


/// LowerBuildVectorv16i8 - Custom lower build_vector of v16i8.
///
static SDValue LowerBuildVectorv16i8(SDValue Op, unsigned NonZeros,
                                       unsigned NumNonZero, unsigned NumZero,
                                       SelectionDAG &DAG, TargetLowering &TLI) {
  if (NumNonZero > 8)
    return SDValue();

  DebugLoc dl = Op.getDebugLoc();
  SDValue V(0, 0);
  bool First = true;
  for (unsigned i = 0; i < 16; ++i) {
    bool ThisIsNonZero = (NonZeros & (1 << i)) != 0;
    if (ThisIsNonZero && First) {
      if (NumZero)
        V = getZeroVector(MVT::v8i16, true, DAG, dl);
      else
        V = DAG.getUNDEF(MVT::v8i16);
      First = false;
    }

    if ((i & 1) != 0) {
      SDValue ThisElt(0, 0), LastElt(0, 0);
      bool LastIsNonZero = (NonZeros & (1 << (i-1))) != 0;
      if (LastIsNonZero) {
        LastElt = DAG.getNode(ISD::ZERO_EXTEND, dl,
                              MVT::i16, Op.getOperand(i-1));
      }
      if (ThisIsNonZero) {
        ThisElt = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i16, Op.getOperand(i));
        ThisElt = DAG.getNode(ISD::SHL, dl, MVT::i16,
                              ThisElt, DAG.getConstant(8, MVT::i8));
        if (LastIsNonZero)
          ThisElt = DAG.getNode(ISD::OR, dl, MVT::i16, ThisElt, LastElt);
      } else
        ThisElt = LastElt;

      if (ThisElt.getNode())
        V = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, MVT::v8i16, V, ThisElt,
                        DAG.getIntPtrConstant(i/2));
    }
  }

  return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v16i8, V);
}

/// LowerBuildVectorv8i16 - Custom lower build_vector of v8i16.
///
static SDValue LowerBuildVectorv8i16(SDValue Op, unsigned NonZeros,
                                       unsigned NumNonZero, unsigned NumZero,
                                       SelectionDAG &DAG, TargetLowering &TLI) {
  if (NumNonZero > 4)
    return SDValue();

  DebugLoc dl = Op.getDebugLoc();
  SDValue V(0, 0);
  bool First = true;
  for (unsigned i = 0; i < 8; ++i) {
    bool isNonZero = (NonZeros & (1 << i)) != 0;
    if (isNonZero) {
      if (First) {
        if (NumZero)
          V = getZeroVector(MVT::v8i16, true, DAG, dl);
        else
          V = DAG.getUNDEF(MVT::v8i16);
        First = false;
      }
      V = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl,
                      MVT::v8i16, V, Op.getOperand(i),
                      DAG.getIntPtrConstant(i));
    }
  }

  return V;
}

/// getVShift - Return a vector logical shift node.
///
static SDValue getVShift(bool isLeft, MVT VT, SDValue SrcOp,
                         unsigned NumBits, SelectionDAG &DAG,
                         const TargetLowering &TLI, DebugLoc dl) {
  bool isMMX = VT.getSizeInBits() == 64;
  MVT ShVT = isMMX ? MVT::v1i64 : MVT::v2i64;
  unsigned Opc = isLeft ? X86ISD::VSHL : X86ISD::VSRL;
  SrcOp = DAG.getNode(ISD::BIT_CONVERT, dl, ShVT, SrcOp);
  return DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                     DAG.getNode(Opc, dl, ShVT, SrcOp,
                             DAG.getConstant(NumBits, TLI.getShiftAmountTy())));
}

SDValue
X86TargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();
  // All zero's are handled with pxor, all one's are handled with pcmpeqd.
  if (ISD::isBuildVectorAllZeros(Op.getNode())
      || ISD::isBuildVectorAllOnes(Op.getNode())) {
    // Canonicalize this to either <4 x i32> or <2 x i32> (SSE vs MMX) to
    // 1) ensure the zero vectors are CSE'd, and 2) ensure that i64 scalars are
    // eliminated on x86-32 hosts.
    if (Op.getValueType() == MVT::v4i32 || Op.getValueType() == MVT::v2i32)
      return Op;

    if (ISD::isBuildVectorAllOnes(Op.getNode()))
      return getOnesVector(Op.getValueType(), DAG, dl);
    return getZeroVector(Op.getValueType(), Subtarget->hasSSE2(), DAG, dl);
  }

  MVT VT = Op.getValueType();
  MVT EVT = VT.getVectorElementType();
  unsigned EVTBits = EVT.getSizeInBits();

  unsigned NumElems = Op.getNumOperands();
  unsigned NumZero  = 0;
  unsigned NumNonZero = 0;
  unsigned NonZeros = 0;
  bool IsAllConstants = true;
  SmallSet<SDValue, 8> Values;
  for (unsigned i = 0; i < NumElems; ++i) {
    SDValue Elt = Op.getOperand(i);
    if (Elt.getOpcode() == ISD::UNDEF)
      continue;
    Values.insert(Elt);
    if (Elt.getOpcode() != ISD::Constant &&
        Elt.getOpcode() != ISD::ConstantFP)
      IsAllConstants = false;
    if (X86::isZeroNode(Elt))
      NumZero++;
    else {
      NonZeros |= (1 << i);
      NumNonZero++;
    }
  }

  if (NumNonZero == 0) {
    // All undef vector. Return an UNDEF.  All zero vectors were handled above.
    return DAG.getUNDEF(VT);
  }

  // Special case for single non-zero, non-undef, element.
  if (NumNonZero == 1) {
    unsigned Idx = CountTrailingZeros_32(NonZeros);
    SDValue Item = Op.getOperand(Idx);

    // If this is an insertion of an i64 value on x86-32, and if the top bits of
    // the value are obviously zero, truncate the value to i32 and do the
    // insertion that way.  Only do this if the value is non-constant or if the
    // value is a constant being inserted into element 0.  It is cheaper to do
    // a constant pool load than it is to do a movd + shuffle.
    if (EVT == MVT::i64 && !Subtarget->is64Bit() &&
        (!IsAllConstants || Idx == 0)) {
      if (DAG.MaskedValueIsZero(Item, APInt::getBitsSet(64, 32, 64))) {
        // Handle MMX and SSE both.
        MVT VecVT = VT == MVT::v2i64 ? MVT::v4i32 : MVT::v2i32;
        unsigned VecElts = VT == MVT::v2i64 ? 4 : 2;

        // Truncate the value (which may itself be a constant) to i32, and
        // convert it to a vector with movd (S2V+shuffle to zero extend).
        Item = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Item);
        Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VecVT, Item);
        Item = getShuffleVectorZeroOrUndef(Item, 0, true,
                                           Subtarget->hasSSE2(), DAG);

        // Now we have our 32-bit value zero extended in the low element of
        // a vector.  If Idx != 0, swizzle it into place.
        if (Idx != 0) {
          SmallVector<int, 4> Mask;
          Mask.push_back(Idx);
          for (unsigned i = 1; i != VecElts; ++i)
            Mask.push_back(i);
          Item = DAG.getVectorShuffle(VecVT, dl, Item,
                                      DAG.getUNDEF(Item.getValueType()), 
                                      &Mask[0]);
        }
        return DAG.getNode(ISD::BIT_CONVERT, dl, Op.getValueType(), Item);
      }
    }

    // If we have a constant or non-constant insertion into the low element of
    // a vector, we can do this with SCALAR_TO_VECTOR + shuffle of zero into
    // the rest of the elements.  This will be matched as movd/movq/movss/movsd
    // depending on what the source datatype is.
    if (Idx == 0) {
      if (NumZero == 0) {
        return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Item);
      } else if (EVT == MVT::i32 || EVT == MVT::f32 || EVT == MVT::f64 ||
          (EVT == MVT::i64 && Subtarget->is64Bit())) {
        Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Item);
        // Turn it into a MOVL (i.e. movss, movsd, or movd) to a zero vector.
        return getShuffleVectorZeroOrUndef(Item, 0, true, Subtarget->hasSSE2(),
                                           DAG);
      } else if (EVT == MVT::i16 || EVT == MVT::i8) {
        Item = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, Item);
        MVT MiddleVT = VT.getSizeInBits() == 64 ? MVT::v2i32 : MVT::v4i32;
        Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MiddleVT, Item);
        Item = getShuffleVectorZeroOrUndef(Item, 0, true,
                                           Subtarget->hasSSE2(), DAG);
        return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Item);
      }
    }

    // Is it a vector logical left shift?
    if (NumElems == 2 && Idx == 1 &&
        X86::isZeroNode(Op.getOperand(0)) &&
        !X86::isZeroNode(Op.getOperand(1))) {
      unsigned NumBits = VT.getSizeInBits();
      return getVShift(true, VT,
                       DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
                                   VT, Op.getOperand(1)),
                       NumBits/2, DAG, *this, dl);
    }

    if (IsAllConstants) // Otherwise, it's better to do a constpool load.
      return SDValue();

    // Otherwise, if this is a vector with i32 or f32 elements, and the element
    // is a non-constant being inserted into an element other than the low one,
    // we can't use a constant pool load.  Instead, use SCALAR_TO_VECTOR (aka
    // movd/movss) to move this into the low element, then shuffle it into
    // place.
    if (EVTBits == 32) {
      Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Item);

      // Turn it into a shuffle of zero and zero-extended scalar to vector.
      Item = getShuffleVectorZeroOrUndef(Item, 0, NumZero > 0,
                                         Subtarget->hasSSE2(), DAG);
      SmallVector<int, 8> MaskVec;
      for (unsigned i = 0; i < NumElems; i++)
        MaskVec.push_back(i == Idx ? 0 : 1);
      return DAG.getVectorShuffle(VT, dl, Item, DAG.getUNDEF(VT), &MaskVec[0]);
    }
  }

  // Splat is obviously ok. Let legalizer expand it to a shuffle.
  if (Values.size() == 1)
    return SDValue();

  // A vector full of immediates; various special cases are already
  // handled, so this is best done with a single constant-pool load.
  if (IsAllConstants)
    return SDValue();

  // Let legalizer expand 2-wide build_vectors.
  if (EVTBits == 64) {
    if (NumNonZero == 1) {
      // One half is zero or undef.
      unsigned Idx = CountTrailingZeros_32(NonZeros);
      SDValue V2 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT,
                                 Op.getOperand(Idx));
      return getShuffleVectorZeroOrUndef(V2, Idx, true,
                                         Subtarget->hasSSE2(), DAG);
    }
    return SDValue();
  }

  // If element VT is < 32 bits, convert it to inserts into a zero vector.
  if (EVTBits == 8 && NumElems == 16) {
    SDValue V = LowerBuildVectorv16i8(Op, NonZeros,NumNonZero,NumZero, DAG,
                                        *this);
    if (V.getNode()) return V;
  }

  if (EVTBits == 16 && NumElems == 8) {
    SDValue V = LowerBuildVectorv8i16(Op, NonZeros,NumNonZero,NumZero, DAG,
                                        *this);
    if (V.getNode()) return V;
  }

  // If element VT is == 32 bits, turn it into a number of shuffles.
  SmallVector<SDValue, 8> V;
  V.resize(NumElems);
  if (NumElems == 4 && NumZero > 0) {
    for (unsigned i = 0; i < 4; ++i) {
      bool isZero = !(NonZeros & (1 << i));
      if (isZero)
        V[i] = getZeroVector(VT, Subtarget->hasSSE2(), DAG, dl);
      else
        V[i] = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Op.getOperand(i));
    }

    for (unsigned i = 0; i < 2; ++i) {
      switch ((NonZeros & (0x3 << i*2)) >> (i*2)) {
        default: break;
        case 0:
          V[i] = V[i*2];  // Must be a zero vector.
          break;
        case 1:
          V[i] = getMOVL(DAG, dl, VT, V[i*2+1], V[i*2]);
          break;
        case 2:
          V[i] = getMOVL(DAG, dl, VT, V[i*2], V[i*2+1]);
          break;
        case 3:
          V[i] = getUnpackl(DAG, dl, VT, V[i*2], V[i*2+1]);
          break;
      }
    }

    SmallVector<int, 8> MaskVec;
    bool Reverse = (NonZeros & 0x3) == 2;
    for (unsigned i = 0; i < 2; ++i)
      MaskVec.push_back(Reverse ? 1-i : i);
    Reverse = ((NonZeros & (0x3 << 2)) >> 2) == 2;
    for (unsigned i = 0; i < 2; ++i)
      MaskVec.push_back(Reverse ? 1-i+NumElems : i+NumElems);
    return DAG.getVectorShuffle(VT, dl, V[0], V[1], &MaskVec[0]);
  }

  if (Values.size() > 2) {
    // If we have SSE 4.1, Expand into a number of inserts unless the number of
    // values to be inserted is equal to the number of elements, in which case
    // use the unpack code below in the hopes of matching the consecutive elts
    // load merge pattern for shuffles. 
    // FIXME: We could probably just check that here directly.
    if (Values.size() < NumElems && VT.getSizeInBits() == 128 && 
        getSubtarget()->hasSSE41()) {
      V[0] = DAG.getUNDEF(VT);
      for (unsigned i = 0; i < NumElems; ++i)
        if (Op.getOperand(i).getOpcode() != ISD::UNDEF)
          V[0] = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, VT, V[0],
                             Op.getOperand(i), DAG.getIntPtrConstant(i));
      return V[0];
    }
    // Expand into a number of unpckl*.
    // e.g. for v4f32
    //   Step 1: unpcklps 0, 2 ==> X: <?, ?, 2, 0>
    //         : unpcklps 1, 3 ==> Y: <?, ?, 3, 1>
    //   Step 2: unpcklps X, Y ==>    <3, 2, 1, 0>
    for (unsigned i = 0; i < NumElems; ++i)
      V[i] = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Op.getOperand(i));
    NumElems >>= 1;
    while (NumElems != 0) {
      for (unsigned i = 0; i < NumElems; ++i)
        V[i] = getUnpackl(DAG, dl, VT, V[i], V[i + NumElems]);
      NumElems >>= 1;
    }
    return V[0];
  }

  return SDValue();
}

// v8i16 shuffles - Prefer shuffles in the following order:
// 1. [all]   pshuflw, pshufhw, optional move
// 2. [ssse3] 1 x pshufb
// 3. [ssse3] 2 x pshufb + 1 x por
// 4. [all]   mov + pshuflw + pshufhw + N x (pextrw + pinsrw)
static
SDValue LowerVECTOR_SHUFFLEv8i16(ShuffleVectorSDNode *SVOp,
                                 SelectionDAG &DAG, X86TargetLowering &TLI) {
  SDValue V1 = SVOp->getOperand(0);
  SDValue V2 = SVOp->getOperand(1);
  DebugLoc dl = SVOp->getDebugLoc();
  SmallVector<int, 8> MaskVals;

  // Determine if more than 1 of the words in each of the low and high quadwords
  // of the result come from the same quadword of one of the two inputs.  Undef
  // mask values count as coming from any quadword, for better codegen.
  SmallVector<unsigned, 4> LoQuad(4);
  SmallVector<unsigned, 4> HiQuad(4);
  BitVector InputQuads(4);
  for (unsigned i = 0; i < 8; ++i) {
    SmallVectorImpl<unsigned> &Quad = i < 4 ? LoQuad : HiQuad;
    int EltIdx = SVOp->getMaskElt(i);
    MaskVals.push_back(EltIdx);
    if (EltIdx < 0) {
      ++Quad[0];
      ++Quad[1];
      ++Quad[2];
      ++Quad[3];
      continue;
    }
    ++Quad[EltIdx / 4];
    InputQuads.set(EltIdx / 4);
  }

  int BestLoQuad = -1;
  unsigned MaxQuad = 1;
  for (unsigned i = 0; i < 4; ++i) {
    if (LoQuad[i] > MaxQuad) {
      BestLoQuad = i;
      MaxQuad = LoQuad[i];
    }
  }

  int BestHiQuad = -1;
  MaxQuad = 1;
  for (unsigned i = 0; i < 4; ++i) {
    if (HiQuad[i] > MaxQuad) {
      BestHiQuad = i;
      MaxQuad = HiQuad[i];
    }
  }

  // For SSSE3, If all 8 words of the result come from only 1 quadword of each
  // of the two input vectors, shuffle them into one input vector so only a 
  // single pshufb instruction is necessary. If There are more than 2 input
  // quads, disable the next transformation since it does not help SSSE3.
  bool V1Used = InputQuads[0] || InputQuads[1];
  bool V2Used = InputQuads[2] || InputQuads[3];
  if (TLI.getSubtarget()->hasSSSE3()) {
    if (InputQuads.count() == 2 && V1Used && V2Used) {
      BestLoQuad = InputQuads.find_first();
      BestHiQuad = InputQuads.find_next(BestLoQuad);
    }
    if (InputQuads.count() > 2) {
      BestLoQuad = -1;
      BestHiQuad = -1;
    }
  }

  // If BestLoQuad or BestHiQuad are set, shuffle the quads together and update
  // the shuffle mask.  If a quad is scored as -1, that means that it contains
  // words from all 4 input quadwords.
  SDValue NewV;
  if (BestLoQuad >= 0 || BestHiQuad >= 0) {
    SmallVector<int, 8> MaskV;
    MaskV.push_back(BestLoQuad < 0 ? 0 : BestLoQuad);
    MaskV.push_back(BestHiQuad < 0 ? 1 : BestHiQuad);
    NewV = DAG.getVectorShuffle(MVT::v2i64, dl, 
                  DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64, V1),
                  DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64, V2), &MaskV[0]);
    NewV = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v8i16, NewV);

    // Rewrite the MaskVals and assign NewV to V1 if NewV now contains all the
    // source words for the shuffle, to aid later transformations.
    bool AllWordsInNewV = true;
    bool InOrder[2] = { true, true };
    for (unsigned i = 0; i != 8; ++i) {
      int idx = MaskVals[i];
      if (idx != (int)i)
        InOrder[i/4] = false;
      if (idx < 0 || (idx/4) == BestLoQuad || (idx/4) == BestHiQuad)
        continue;
      AllWordsInNewV = false;
      break;
    }

    bool pshuflw = AllWordsInNewV, pshufhw = AllWordsInNewV;
    if (AllWordsInNewV) {
      for (int i = 0; i != 8; ++i) {
        int idx = MaskVals[i];
        if (idx < 0)
          continue;
        idx = MaskVals[i] = (idx / 4) == BestLoQuad ? (idx & 3) : (idx & 3) + 4; 
        if ((idx != i) && idx < 4)
          pshufhw = false;
        if ((idx != i) && idx > 3)
          pshuflw = false;
      }
      V1 = NewV;
      V2Used = false;
      BestLoQuad = 0;
      BestHiQuad = 1;
    }

    // If we've eliminated the use of V2, and the new mask is a pshuflw or
    // pshufhw, that's as cheap as it gets.  Return the new shuffle.
    if ((pshufhw && InOrder[0]) || (pshuflw && InOrder[1])) {
      return DAG.getVectorShuffle(MVT::v8i16, dl, NewV, 
                                  DAG.getUNDEF(MVT::v8i16), &MaskVals[0]);
    }
  }
  
  // If we have SSSE3, and all words of the result are from 1 input vector,
  // case 2 is generated, otherwise case 3 is generated.  If no SSSE3
  // is present, fall back to case 4.
  if (TLI.getSubtarget()->hasSSSE3()) {
    SmallVector<SDValue,16> pshufbMask;
    
    // If we have elements from both input vectors, set the high bit of the
    // shuffle mask element to zero out elements that come from V2 in the V1 
    // mask, and elements that come from V1 in the V2 mask, so that the two
    // results can be OR'd together.
    bool TwoInputs = V1Used && V2Used;
    for (unsigned i = 0; i != 8; ++i) {
      int EltIdx = MaskVals[i] * 2;
      if (TwoInputs && (EltIdx >= 16)) {
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        continue;
      }
      pshufbMask.push_back(DAG.getConstant(EltIdx,   MVT::i8));
      pshufbMask.push_back(DAG.getConstant(EltIdx+1, MVT::i8));
    }
    V1 = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v16i8, V1);
    V1 = DAG.getNode(X86ISD::PSHUFB, dl, MVT::v16i8, V1, 
                     DAG.getNode(ISD::BUILD_VECTOR, dl,
                                 MVT::v16i8, &pshufbMask[0], 16));
    if (!TwoInputs)
      return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v8i16, V1);
    
    // Calculate the shuffle mask for the second input, shuffle it, and
    // OR it with the first shuffled input.
    pshufbMask.clear();
    for (unsigned i = 0; i != 8; ++i) {
      int EltIdx = MaskVals[i] * 2;
      if (EltIdx < 16) {
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        continue;
      }
      pshufbMask.push_back(DAG.getConstant(EltIdx - 16, MVT::i8));
      pshufbMask.push_back(DAG.getConstant(EltIdx - 15, MVT::i8));
    }
    V2 = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v16i8, V2);
    V2 = DAG.getNode(X86ISD::PSHUFB, dl, MVT::v16i8, V2, 
                     DAG.getNode(ISD::BUILD_VECTOR, dl,
                                 MVT::v16i8, &pshufbMask[0], 16));
    V1 = DAG.getNode(ISD::OR, dl, MVT::v16i8, V1, V2);
    return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v8i16, V1);
  }

  // If BestLoQuad >= 0, generate a pshuflw to put the low elements in order,
  // and update MaskVals with new element order.
  BitVector InOrder(8);
  if (BestLoQuad >= 0) {
    SmallVector<int, 8> MaskV;
    for (int i = 0; i != 4; ++i) {
      int idx = MaskVals[i];
      if (idx < 0) {
        MaskV.push_back(-1);
        InOrder.set(i);
      } else if ((idx / 4) == BestLoQuad) {
        MaskV.push_back(idx & 3);
        InOrder.set(i);
      } else {
        MaskV.push_back(-1);
      }
    }
    for (unsigned i = 4; i != 8; ++i)
      MaskV.push_back(i);
    NewV = DAG.getVectorShuffle(MVT::v8i16, dl, NewV, DAG.getUNDEF(MVT::v8i16),
                                &MaskV[0]);
  }
  
  // If BestHi >= 0, generate a pshufhw to put the high elements in order,
  // and update MaskVals with the new element order.
  if (BestHiQuad >= 0) {
    SmallVector<int, 8> MaskV;
    for (unsigned i = 0; i != 4; ++i)
      MaskV.push_back(i);
    for (unsigned i = 4; i != 8; ++i) {
      int idx = MaskVals[i];
      if (idx < 0) {
        MaskV.push_back(-1);
        InOrder.set(i);
      } else if ((idx / 4) == BestHiQuad) {
        MaskV.push_back((idx & 3) + 4);
        InOrder.set(i);
      } else {
        MaskV.push_back(-1);
      }
    }
    NewV = DAG.getVectorShuffle(MVT::v8i16, dl, NewV, DAG.getUNDEF(MVT::v8i16),
                                &MaskV[0]);
  }
  
  // In case BestHi & BestLo were both -1, which means each quadword has a word
  // from each of the four input quadwords, calculate the InOrder bitvector now
  // before falling through to the insert/extract cleanup.
  if (BestLoQuad == -1 && BestHiQuad == -1) {
    NewV = V1;
    for (int i = 0; i != 8; ++i)
      if (MaskVals[i] < 0 || MaskVals[i] == i)
        InOrder.set(i);
  }
  
  // The other elements are put in the right place using pextrw and pinsrw.
  for (unsigned i = 0; i != 8; ++i) {
    if (InOrder[i])
      continue;
    int EltIdx = MaskVals[i];
    if (EltIdx < 0)
      continue;
    SDValue ExtOp = (EltIdx < 8)
    ? DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i16, V1,
                  DAG.getIntPtrConstant(EltIdx))
    : DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i16, V2,
                  DAG.getIntPtrConstant(EltIdx - 8));
    NewV = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, MVT::v8i16, NewV, ExtOp,
                       DAG.getIntPtrConstant(i));
  }
  return NewV;
}

// v16i8 shuffles - Prefer shuffles in the following order:
// 1. [ssse3] 1 x pshufb
// 2. [ssse3] 2 x pshufb + 1 x por
// 3. [all]   v8i16 shuffle + N x pextrw + rotate + pinsrw
static
SDValue LowerVECTOR_SHUFFLEv16i8(ShuffleVectorSDNode *SVOp,
                                 SelectionDAG &DAG, X86TargetLowering &TLI) {
  SDValue V1 = SVOp->getOperand(0);
  SDValue V2 = SVOp->getOperand(1);
  DebugLoc dl = SVOp->getDebugLoc();
  SmallVector<int, 16> MaskVals;
  SVOp->getMask(MaskVals);
  
  // If we have SSSE3, case 1 is generated when all result bytes come from
  // one of  the inputs.  Otherwise, case 2 is generated.  If no SSSE3 is 
  // present, fall back to case 3.
  // FIXME: kill V2Only once shuffles are canonizalized by getNode.
  bool V1Only = true;
  bool V2Only = true;
  for (unsigned i = 0; i < 16; ++i) {
    int EltIdx = MaskVals[i];
    if (EltIdx < 0)
      continue;
    if (EltIdx < 16)
      V2Only = false;
    else
      V1Only = false;
  }
  
  // If SSSE3, use 1 pshufb instruction per vector with elements in the result.
  if (TLI.getSubtarget()->hasSSSE3()) {
    SmallVector<SDValue,16> pshufbMask;
    
    // If all result elements are from one input vector, then only translate
    // undef mask values to 0x80 (zero out result) in the pshufb mask. 
    //
    // Otherwise, we have elements from both input vectors, and must zero out
    // elements that come from V2 in the first mask, and V1 in the second mask
    // so that we can OR them together.
    bool TwoInputs = !(V1Only || V2Only);
    for (unsigned i = 0; i != 16; ++i) {
      int EltIdx = MaskVals[i];
      if (EltIdx < 0 || (TwoInputs && EltIdx >= 16)) {
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        continue;
      }
      pshufbMask.push_back(DAG.getConstant(EltIdx, MVT::i8));
    }
    // If all the elements are from V2, assign it to V1 and return after
    // building the first pshufb.
    if (V2Only)
      V1 = V2;
    V1 = DAG.getNode(X86ISD::PSHUFB, dl, MVT::v16i8, V1,
                     DAG.getNode(ISD::BUILD_VECTOR, dl,
                                 MVT::v16i8, &pshufbMask[0], 16));
    if (!TwoInputs)
      return V1;
    
    // Calculate the shuffle mask for the second input, shuffle it, and
    // OR it with the first shuffled input.
    pshufbMask.clear();
    for (unsigned i = 0; i != 16; ++i) {
      int EltIdx = MaskVals[i];
      if (EltIdx < 16) {
        pshufbMask.push_back(DAG.getConstant(0x80, MVT::i8));
        continue;
      }
      pshufbMask.push_back(DAG.getConstant(EltIdx - 16, MVT::i8));
    }
    V2 = DAG.getNode(X86ISD::PSHUFB, dl, MVT::v16i8, V2,
                     DAG.getNode(ISD::BUILD_VECTOR, dl,
                                 MVT::v16i8, &pshufbMask[0], 16));
    return DAG.getNode(ISD::OR, dl, MVT::v16i8, V1, V2);
  }
  
  // No SSSE3 - Calculate in place words and then fix all out of place words
  // With 0-16 extracts & inserts.  Worst case is 16 bytes out of order from
  // the 16 different words that comprise the two doublequadword input vectors.
  V1 = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v8i16, V1);
  V2 = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v8i16, V2);
  SDValue NewV = V2Only ? V2 : V1;
  for (int i = 0; i != 8; ++i) {
    int Elt0 = MaskVals[i*2];
    int Elt1 = MaskVals[i*2+1];
    
    // This word of the result is all undef, skip it.
    if (Elt0 < 0 && Elt1 < 0)
      continue;
    
    // This word of the result is already in the correct place, skip it.
    if (V1Only && (Elt0 == i*2) && (Elt1 == i*2+1))
      continue;
    if (V2Only && (Elt0 == i*2+16) && (Elt1 == i*2+17))
      continue;
    
    SDValue Elt0Src = Elt0 < 16 ? V1 : V2;
    SDValue Elt1Src = Elt1 < 16 ? V1 : V2;
    SDValue InsElt;

    // If Elt0 and Elt1 are defined, are consecutive, and can be load
    // using a single extract together, load it and store it.
    if ((Elt0 >= 0) && ((Elt0 + 1) == Elt1) && ((Elt0 & 1) == 0)) {
      InsElt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i16, Elt1Src,
                           DAG.getIntPtrConstant(Elt1 / 2));
      NewV = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, MVT::v8i16, NewV, InsElt,
                        DAG.getIntPtrConstant(i));
      continue;
    }

    // If Elt1 is defined, extract it from the appropriate source.  If the
    // source byte is not also odd, shift the extracted word left 8 bits
    // otherwise clear the bottom 8 bits if we need to do an or.
    if (Elt1 >= 0) {
      InsElt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i16, Elt1Src,
                           DAG.getIntPtrConstant(Elt1 / 2));
      if ((Elt1 & 1) == 0)
        InsElt = DAG.getNode(ISD::SHL, dl, MVT::i16, InsElt,
                             DAG.getConstant(8, TLI.getShiftAmountTy()));
      else if (Elt0 >= 0)
        InsElt = DAG.getNode(ISD::AND, dl, MVT::i16, InsElt,
                             DAG.getConstant(0xFF00, MVT::i16));
    }
    // If Elt0 is defined, extract it from the appropriate source.  If the
    // source byte is not also even, shift the extracted word right 8 bits. If
    // Elt1 was also defined, OR the extracted values together before
    // inserting them in the result.
    if (Elt0 >= 0) {
      SDValue InsElt0 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i16,
                                    Elt0Src, DAG.getIntPtrConstant(Elt0 / 2));
      if ((Elt0 & 1) != 0)
        InsElt0 = DAG.getNode(ISD::SRL, dl, MVT::i16, InsElt0,
                              DAG.getConstant(8, TLI.getShiftAmountTy()));
      else if (Elt1 >= 0)
        InsElt0 = DAG.getNode(ISD::AND, dl, MVT::i16, InsElt0,
                             DAG.getConstant(0x00FF, MVT::i16));
      InsElt = Elt1 >= 0 ? DAG.getNode(ISD::OR, dl, MVT::i16, InsElt, InsElt0)
                         : InsElt0;
    }
    NewV = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, MVT::v8i16, NewV, InsElt,
                       DAG.getIntPtrConstant(i));
  }
  return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v16i8, NewV);
}

/// RewriteAsNarrowerShuffle - Try rewriting v8i16 and v16i8 shuffles as 4 wide
/// ones, or rewriting v4i32 / v2f32 as 2 wide ones if possible. This can be
/// done when every pair / quad of shuffle mask elements point to elements in
/// the right sequence. e.g.
/// vector_shuffle <>, <>, < 3, 4, | 10, 11, | 0, 1, | 14, 15>
static
SDValue RewriteAsNarrowerShuffle(ShuffleVectorSDNode *SVOp,
                                 SelectionDAG &DAG,
                                 TargetLowering &TLI, DebugLoc dl) {
  MVT VT = SVOp->getValueType(0);
  SDValue V1 = SVOp->getOperand(0);
  SDValue V2 = SVOp->getOperand(1);
  unsigned NumElems = VT.getVectorNumElements();
  unsigned NewWidth = (NumElems == 4) ? 2 : 4;
  MVT MaskVT = MVT::getIntVectorWithNumElements(NewWidth);
  MVT MaskEltVT = MaskVT.getVectorElementType();
  MVT NewVT = MaskVT;
  switch (VT.getSimpleVT()) {
  default: assert(false && "Unexpected!");
  case MVT::v4f32: NewVT = MVT::v2f64; break;
  case MVT::v4i32: NewVT = MVT::v2i64; break;
  case MVT::v8i16: NewVT = MVT::v4i32; break;
  case MVT::v16i8: NewVT = MVT::v4i32; break;
  }

  if (NewWidth == 2) {
    if (VT.isInteger())
      NewVT = MVT::v2i64;
    else
      NewVT = MVT::v2f64;
  }
  int Scale = NumElems / NewWidth;
  SmallVector<int, 8> MaskVec;
  for (unsigned i = 0; i < NumElems; i += Scale) {
    int StartIdx = -1;
    for (int j = 0; j < Scale; ++j) {
      int EltIdx = SVOp->getMaskElt(i+j);
      if (EltIdx < 0)
        continue;
      if (StartIdx == -1)
        StartIdx = EltIdx - (EltIdx % Scale);
      if (EltIdx != StartIdx + j)
        return SDValue();
    }
    if (StartIdx == -1)
      MaskVec.push_back(-1);
    else
      MaskVec.push_back(StartIdx / Scale);
  }

  V1 = DAG.getNode(ISD::BIT_CONVERT, dl, NewVT, V1);
  V2 = DAG.getNode(ISD::BIT_CONVERT, dl, NewVT, V2);
  return DAG.getVectorShuffle(NewVT, dl, V1, V2, &MaskVec[0]);
}

/// getVZextMovL - Return a zero-extending vector move low node.
///
static SDValue getVZextMovL(MVT VT, MVT OpVT,
                            SDValue SrcOp, SelectionDAG &DAG,
                            const X86Subtarget *Subtarget, DebugLoc dl) {
  if (VT == MVT::v2f64 || VT == MVT::v4f32) {
    LoadSDNode *LD = NULL;
    if (!isScalarLoadToVector(SrcOp.getNode(), &LD))
      LD = dyn_cast<LoadSDNode>(SrcOp);
    if (!LD) {
      // movssrr and movsdrr do not clear top bits. Try to use movd, movq
      // instead.
      MVT EVT = (OpVT == MVT::v2f64) ? MVT::i64 : MVT::i32;
      if ((EVT != MVT::i64 || Subtarget->is64Bit()) &&
          SrcOp.getOpcode() == ISD::SCALAR_TO_VECTOR &&
          SrcOp.getOperand(0).getOpcode() == ISD::BIT_CONVERT &&
          SrcOp.getOperand(0).getOperand(0).getValueType() == EVT) {
        // PR2108
        OpVT = (OpVT == MVT::v2f64) ? MVT::v2i64 : MVT::v4i32;
        return DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                           DAG.getNode(X86ISD::VZEXT_MOVL, dl, OpVT,
                                       DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
                                                   OpVT,
                                                   SrcOp.getOperand(0)
                                                          .getOperand(0))));
      }
    }
  }

  return DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                     DAG.getNode(X86ISD::VZEXT_MOVL, dl, OpVT,
                                 DAG.getNode(ISD::BIT_CONVERT, dl,
                                             OpVT, SrcOp)));
}

/// LowerVECTOR_SHUFFLE_4wide - Handle all 4 wide cases with a number of
/// shuffles.
static SDValue
LowerVECTOR_SHUFFLE_4wide(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG) {
  SDValue V1 = SVOp->getOperand(0);
  SDValue V2 = SVOp->getOperand(1);
  DebugLoc dl = SVOp->getDebugLoc();
  MVT VT = SVOp->getValueType(0);
  
  SmallVector<std::pair<int, int>, 8> Locs;
  Locs.resize(4);
  SmallVector<int, 8> Mask1(4U, -1);
  SmallVector<int, 8> PermMask;
  SVOp->getMask(PermMask);

  unsigned NumHi = 0;
  unsigned NumLo = 0;
  for (unsigned i = 0; i != 4; ++i) {
    int Idx = PermMask[i];
    if (Idx < 0) {
      Locs[i] = std::make_pair(-1, -1);
    } else {
      assert(Idx < 8 && "Invalid VECTOR_SHUFFLE index!");
      if (Idx < 4) {
        Locs[i] = std::make_pair(0, NumLo);
        Mask1[NumLo] = Idx;
        NumLo++;
      } else {
        Locs[i] = std::make_pair(1, NumHi);
        if (2+NumHi < 4)
          Mask1[2+NumHi] = Idx;
        NumHi++;
      }
    }
  }

  if (NumLo <= 2 && NumHi <= 2) {
    // If no more than two elements come from either vector. This can be
    // implemented with two shuffles. First shuffle gather the elements.
    // The second shuffle, which takes the first shuffle as both of its
    // vector operands, put the elements into the right order.
    V1 = DAG.getVectorShuffle(VT, dl, V1, V2, &Mask1[0]);

    SmallVector<int, 8> Mask2(4U, -1);
    
    for (unsigned i = 0; i != 4; ++i) {
      if (Locs[i].first == -1)
        continue;
      else {
        unsigned Idx = (i < 2) ? 0 : 4;
        Idx += Locs[i].first * 2 + Locs[i].second;
        Mask2[i] = Idx;
      }
    }

    return DAG.getVectorShuffle(VT, dl, V1, V1, &Mask2[0]);
  } else if (NumLo == 3 || NumHi == 3) {
    // Otherwise, we must have three elements from one vector, call it X, and
    // one element from the other, call it Y.  First, use a shufps to build an
    // intermediate vector with the one element from Y and the element from X
    // that will be in the same half in the final destination (the indexes don't
    // matter). Then, use a shufps to build the final vector, taking the half
    // containing the element from Y from the intermediate, and the other half
    // from X.
    if (NumHi == 3) {
      // Normalize it so the 3 elements come from V1.
      CommuteVectorShuffleMask(PermMask, VT);
      std::swap(V1, V2);
    }

    // Find the element from V2.
    unsigned HiIndex;
    for (HiIndex = 0; HiIndex < 3; ++HiIndex) {
      int Val = PermMask[HiIndex];
      if (Val < 0)
        continue;
      if (Val >= 4)
        break;
    }

    Mask1[0] = PermMask[HiIndex];
    Mask1[1] = -1;
    Mask1[2] = PermMask[HiIndex^1];
    Mask1[3] = -1;
    V2 = DAG.getVectorShuffle(VT, dl, V1, V2, &Mask1[0]);

    if (HiIndex >= 2) {
      Mask1[0] = PermMask[0];
      Mask1[1] = PermMask[1];
      Mask1[2] = HiIndex & 1 ? 6 : 4;
      Mask1[3] = HiIndex & 1 ? 4 : 6;
      return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask1[0]);
    } else {
      Mask1[0] = HiIndex & 1 ? 2 : 0;
      Mask1[1] = HiIndex & 1 ? 0 : 2;
      Mask1[2] = PermMask[2];
      Mask1[3] = PermMask[3];
      if (Mask1[2] >= 0)
        Mask1[2] += 4;
      if (Mask1[3] >= 0)
        Mask1[3] += 4;
      return DAG.getVectorShuffle(VT, dl, V2, V1, &Mask1[0]);
    }
  }

  // Break it into (shuffle shuffle_hi, shuffle_lo).
  Locs.clear();
  SmallVector<int,8> LoMask(4U, -1);
  SmallVector<int,8> HiMask(4U, -1);

  SmallVector<int,8> *MaskPtr = &LoMask;
  unsigned MaskIdx = 0;
  unsigned LoIdx = 0;
  unsigned HiIdx = 2;
  for (unsigned i = 0; i != 4; ++i) {
    if (i == 2) {
      MaskPtr = &HiMask;
      MaskIdx = 1;
      LoIdx = 0;
      HiIdx = 2;
    }
    int Idx = PermMask[i];
    if (Idx < 0) {
      Locs[i] = std::make_pair(-1, -1);
    } else if (Idx < 4) {
      Locs[i] = std::make_pair(MaskIdx, LoIdx);
      (*MaskPtr)[LoIdx] = Idx;
      LoIdx++;
    } else {
      Locs[i] = std::make_pair(MaskIdx, HiIdx);
      (*MaskPtr)[HiIdx] = Idx;
      HiIdx++;
    }
  }

  SDValue LoShuffle = DAG.getVectorShuffle(VT, dl, V1, V2, &LoMask[0]);
  SDValue HiShuffle = DAG.getVectorShuffle(VT, dl, V1, V2, &HiMask[0]);
  SmallVector<int, 8> MaskOps;
  for (unsigned i = 0; i != 4; ++i) {
    if (Locs[i].first == -1) {
      MaskOps.push_back(-1);
    } else {
      unsigned Idx = Locs[i].first * 4 + Locs[i].second;
      MaskOps.push_back(Idx);
    }
  }
  return DAG.getVectorShuffle(VT, dl, LoShuffle, HiShuffle, &MaskOps[0]);
}

SDValue
X86TargetLowering::LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) {
  ShuffleVectorSDNode *SVOp = cast<ShuffleVectorSDNode>(Op);
  SDValue V1 = Op.getOperand(0);
  SDValue V2 = Op.getOperand(1);
  MVT VT = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();
  unsigned NumElems = VT.getVectorNumElements();
  bool isMMX = VT.getSizeInBits() == 64;
  bool V1IsUndef = V1.getOpcode() == ISD::UNDEF;
  bool V2IsUndef = V2.getOpcode() == ISD::UNDEF;
  bool V1IsSplat = false;
  bool V2IsSplat = false;

  if (isZeroShuffle(SVOp))
    return getZeroVector(VT, Subtarget->hasSSE2(), DAG, dl);

  // Promote splats to v4f32.
  if (SVOp->isSplat()) {
    if (isMMX || NumElems < 4) 
      return Op;
    return PromoteSplat(SVOp, DAG, Subtarget->hasSSE2());
  }

  // If the shuffle can be profitably rewritten as a narrower shuffle, then
  // do it!
  if (VT == MVT::v8i16 || VT == MVT::v16i8) {
    SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG, *this, dl);
    if (NewOp.getNode())
      return DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                         LowerVECTOR_SHUFFLE(NewOp, DAG));
  } else if ((VT == MVT::v4i32 || (VT == MVT::v4f32 && Subtarget->hasSSE2()))) {
    // FIXME: Figure out a cleaner way to do this.
    // Try to make use of movq to zero out the top part.
    if (ISD::isBuildVectorAllZeros(V2.getNode())) {
      SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG, *this, dl);
      if (NewOp.getNode()) {
        if (isCommutedMOVL(cast<ShuffleVectorSDNode>(NewOp), true, false))
          return getVZextMovL(VT, NewOp.getValueType(), NewOp.getOperand(0),
                              DAG, Subtarget, dl);
      }
    } else if (ISD::isBuildVectorAllZeros(V1.getNode())) {
      SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG, *this, dl);
      if (NewOp.getNode() && X86::isMOVLMask(cast<ShuffleVectorSDNode>(NewOp)))
        return getVZextMovL(VT, NewOp.getValueType(), NewOp.getOperand(1),
                            DAG, Subtarget, dl);
    }
  }
  
  if (X86::isPSHUFDMask(SVOp))
    return Op;
  
  // Check if this can be converted into a logical shift.
  bool isLeft = false;
  unsigned ShAmt = 0;
  SDValue ShVal;
  bool isShift = getSubtarget()->hasSSE2() &&
  isVectorShift(SVOp, DAG, isLeft, ShVal, ShAmt);
  if (isShift && ShVal.hasOneUse()) {
    // If the shifted value has multiple uses, it may be cheaper to use
    // v_set0 + movlhps or movhlps, etc.
    MVT EVT = VT.getVectorElementType();
    ShAmt *= EVT.getSizeInBits();
    return getVShift(isLeft, VT, ShVal, ShAmt, DAG, *this, dl);
  }
  
  if (X86::isMOVLMask(SVOp)) {
    if (V1IsUndef)
      return V2;
    if (ISD::isBuildVectorAllZeros(V1.getNode()))
      return getVZextMovL(VT, VT, V2, DAG, Subtarget, dl);
    if (!isMMX)
      return Op;
  }
  
  // FIXME: fold these into legal mask.
  if (!isMMX && (X86::isMOVSHDUPMask(SVOp) ||
                 X86::isMOVSLDUPMask(SVOp) ||
                 X86::isMOVHLPSMask(SVOp) ||
                 X86::isMOVHPMask(SVOp) ||
                 X86::isMOVLPMask(SVOp)))
    return Op;

  if (ShouldXformToMOVHLPS(SVOp) ||
      ShouldXformToMOVLP(V1.getNode(), V2.getNode(), SVOp))
    return CommuteVectorShuffle(SVOp, DAG);

  if (isShift) {
    // No better options. Use a vshl / vsrl.
    MVT EVT = VT.getVectorElementType();
    ShAmt *= EVT.getSizeInBits();
    return getVShift(isLeft, VT, ShVal, ShAmt, DAG, *this, dl);
  }
  
  bool Commuted = false;
  // FIXME: This should also accept a bitcast of a splat?  Be careful, not
  // 1,1,1,1 -> v8i16 though.
  V1IsSplat = isSplatVector(V1.getNode());
  V2IsSplat = isSplatVector(V2.getNode());

  // Canonicalize the splat or undef, if present, to be on the RHS.
  if ((V1IsSplat || V1IsUndef) && !(V2IsSplat || V2IsUndef)) {
    Op = CommuteVectorShuffle(SVOp, DAG);
    SVOp = cast<ShuffleVectorSDNode>(Op);
    V1 = SVOp->getOperand(0);
    V2 = SVOp->getOperand(1);
    std::swap(V1IsSplat, V2IsSplat);
    std::swap(V1IsUndef, V2IsUndef);
    Commuted = true;
  }

  if (isCommutedMOVL(SVOp, V2IsSplat, V2IsUndef)) {
    // Shuffling low element of v1 into undef, just return v1.
    if (V2IsUndef) 
      return V1;
    // If V2 is a splat, the mask may be malformed such as <4,3,3,3>, which
    // the instruction selector will not match, so get a canonical MOVL with
    // swapped operands to undo the commute.
    return getMOVL(DAG, dl, VT, V2, V1);
  }

  if (X86::isUNPCKL_v_undef_Mask(SVOp) ||
      X86::isUNPCKH_v_undef_Mask(SVOp) ||
      X86::isUNPCKLMask(SVOp) ||
      X86::isUNPCKHMask(SVOp))
    return Op;

  if (V2IsSplat) {
    // Normalize mask so all entries that point to V2 points to its first
    // element then try to match unpck{h|l} again. If match, return a
    // new vector_shuffle with the corrected mask.
    SDValue NewMask = NormalizeMask(SVOp, DAG);
    ShuffleVectorSDNode *NSVOp = cast<ShuffleVectorSDNode>(NewMask);
    if (NSVOp != SVOp) {
      if (X86::isUNPCKLMask(NSVOp, true)) {
        return NewMask;
      } else if (X86::isUNPCKHMask(NSVOp, true)) {
        return NewMask;
      }
    }
  }

  if (Commuted) {
    // Commute is back and try unpck* again.
    // FIXME: this seems wrong.
    SDValue NewOp = CommuteVectorShuffle(SVOp, DAG);
    ShuffleVectorSDNode *NewSVOp = cast<ShuffleVectorSDNode>(NewOp);
    if (X86::isUNPCKL_v_undef_Mask(NewSVOp) ||
        X86::isUNPCKH_v_undef_Mask(NewSVOp) ||
        X86::isUNPCKLMask(NewSVOp) ||
        X86::isUNPCKHMask(NewSVOp))
      return NewOp;
  }

  // FIXME: for mmx, bitcast v2i32 to v4i16 for shuffle.

  // Normalize the node to match x86 shuffle ops if needed
  if (!isMMX && V2.getOpcode() != ISD::UNDEF && isCommutedSHUFP(SVOp))
    return CommuteVectorShuffle(SVOp, DAG);

  // Check for legal shuffle and return?
  SmallVector<int, 16> PermMask;
  SVOp->getMask(PermMask);
  if (isShuffleMaskLegal(PermMask, VT))
    return Op;
  
  // Handle v8i16 specifically since SSE can do byte extraction and insertion.
  if (VT == MVT::v8i16) {
    SDValue NewOp = LowerVECTOR_SHUFFLEv8i16(SVOp, DAG, *this);
    if (NewOp.getNode())
      return NewOp;
  }

  if (VT == MVT::v16i8) {
    SDValue NewOp = LowerVECTOR_SHUFFLEv16i8(SVOp, DAG, *this);
    if (NewOp.getNode())
      return NewOp;
  }
  
  // Handle all 4 wide cases with a number of shuffles except for MMX.
  if (NumElems == 4 && !isMMX)
    return LowerVECTOR_SHUFFLE_4wide(SVOp, DAG);

  return SDValue();
}

SDValue
X86TargetLowering::LowerEXTRACT_VECTOR_ELT_SSE4(SDValue Op,
                                                SelectionDAG &DAG) {
  MVT VT = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();
  if (VT.getSizeInBits() == 8) {
    SDValue Extract = DAG.getNode(X86ISD::PEXTRB, dl, MVT::i32,
                                    Op.getOperand(0), Op.getOperand(1));
    SDValue Assert  = DAG.getNode(ISD::AssertZext, dl, MVT::i32, Extract,
                                    DAG.getValueType(VT));
    return DAG.getNode(ISD::TRUNCATE, dl, VT, Assert);
  } else if (VT.getSizeInBits() == 16) {
    unsigned Idx = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
    // If Idx is 0, it's cheaper to do a move instead of a pextrw.
    if (Idx == 0)
      return DAG.getNode(ISD::TRUNCATE, dl, MVT::i16,
                         DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i32,
                                     DAG.getNode(ISD::BIT_CONVERT, dl,
                                                 MVT::v4i32,
                                                 Op.getOperand(0)),
                                     Op.getOperand(1)));
    SDValue Extract = DAG.getNode(X86ISD::PEXTRW, dl, MVT::i32,
                                    Op.getOperand(0), Op.getOperand(1));
    SDValue Assert  = DAG.getNode(ISD::AssertZext, dl, MVT::i32, Extract,
                                    DAG.getValueType(VT));
    return DAG.getNode(ISD::TRUNCATE, dl, VT, Assert);
  } else if (VT == MVT::f32) {
    // EXTRACTPS outputs to a GPR32 register which will require a movd to copy
    // the result back to FR32 register. It's only worth matching if the
    // result has a single use which is a store or a bitcast to i32.  And in
    // the case of a store, it's not worth it if the index is a constant 0,
    // because a MOVSSmr can be used instead, which is smaller and faster.
    if (!Op.hasOneUse())
      return SDValue();
    SDNode *User = *Op.getNode()->use_begin();
    if ((User->getOpcode() != ISD::STORE ||
         (isa<ConstantSDNode>(Op.getOperand(1)) &&
          cast<ConstantSDNode>(Op.getOperand(1))->isNullValue())) &&
        (User->getOpcode() != ISD::BIT_CONVERT ||
         User->getValueType(0) != MVT::i32))
      return SDValue();
    SDValue Extract = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i32,
                                  DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v4i32,
                                              Op.getOperand(0)),
                                              Op.getOperand(1));
    return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, Extract);
  } else if (VT == MVT::i32) {
    // ExtractPS works with constant index.
    if (isa<ConstantSDNode>(Op.getOperand(1)))
      return Op;
  }
  return SDValue();
}


SDValue
X86TargetLowering::LowerEXTRACT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) {
  if (!isa<ConstantSDNode>(Op.getOperand(1)))
    return SDValue();

  if (Subtarget->hasSSE41()) {
    SDValue Res = LowerEXTRACT_VECTOR_ELT_SSE4(Op, DAG);
    if (Res.getNode())
      return Res;
  }

  MVT VT = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();
  // TODO: handle v16i8.
  if (VT.getSizeInBits() == 16) {
    SDValue Vec = Op.getOperand(0);
    unsigned Idx = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
    if (Idx == 0)
      return DAG.getNode(ISD::TRUNCATE, dl, MVT::i16,
                         DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i32,
                                     DAG.getNode(ISD::BIT_CONVERT, dl,
                                                 MVT::v4i32, Vec),
                                     Op.getOperand(1)));
    // Transform it so it match pextrw which produces a 32-bit result.
    MVT EVT = (MVT::SimpleValueType)(VT.getSimpleVT()+1);
    SDValue Extract = DAG.getNode(X86ISD::PEXTRW, dl, EVT,
                                    Op.getOperand(0), Op.getOperand(1));
    SDValue Assert  = DAG.getNode(ISD::AssertZext, dl, EVT, Extract,
                                    DAG.getValueType(VT));
    return DAG.getNode(ISD::TRUNCATE, dl, VT, Assert);
  } else if (VT.getSizeInBits() == 32) {
    unsigned Idx = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
    if (Idx == 0)
      return Op;
    
    // SHUFPS the element to the lowest double word, then movss.
    int Mask[4] = { Idx, -1, -1, -1 };
    MVT VVT = Op.getOperand(0).getValueType();
    SDValue Vec = DAG.getVectorShuffle(VVT, dl, Op.getOperand(0), 
                                       DAG.getUNDEF(VVT), Mask);
    return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, VT, Vec,
                       DAG.getIntPtrConstant(0));
  } else if (VT.getSizeInBits() == 64) {
    // FIXME: .td only matches this for <2 x f64>, not <2 x i64> on 32b
    // FIXME: seems like this should be unnecessary if mov{h,l}pd were taught
    //        to match extract_elt for f64.
    unsigned Idx = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
    if (Idx == 0)
      return Op;

    // UNPCKHPD the element to the lowest double word, then movsd.
    // Note if the lower 64 bits of the result of the UNPCKHPD is then stored
    // to a f64mem, the whole operation is folded into a single MOVHPDmr.
    int Mask[2] = { 1, -1 };
    MVT VVT = Op.getOperand(0).getValueType();
    SDValue Vec = DAG.getVectorShuffle(VVT, dl, Op.getOperand(0), 
                                       DAG.getUNDEF(VVT), Mask);
    return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, VT, Vec,
                       DAG.getIntPtrConstant(0));
  }

  return SDValue();
}

SDValue
X86TargetLowering::LowerINSERT_VECTOR_ELT_SSE4(SDValue Op, SelectionDAG &DAG){
  MVT VT = Op.getValueType();
  MVT EVT = VT.getVectorElementType();
  DebugLoc dl = Op.getDebugLoc();

  SDValue N0 = Op.getOperand(0);
  SDValue N1 = Op.getOperand(1);
  SDValue N2 = Op.getOperand(2);

  if ((EVT.getSizeInBits() == 8 || EVT.getSizeInBits() == 16) &&
      isa<ConstantSDNode>(N2)) {
    unsigned Opc = (EVT.getSizeInBits() == 8) ? X86ISD::PINSRB
                                              : X86ISD::PINSRW;
    // Transform it so it match pinsr{b,w} which expects a GR32 as its second
    // argument.
    if (N1.getValueType() != MVT::i32)
      N1 = DAG.getNode(ISD::ANY_EXTEND, dl, MVT::i32, N1);
    if (N2.getValueType() != MVT::i32)
      N2 = DAG.getIntPtrConstant(cast<ConstantSDNode>(N2)->getZExtValue());
    return DAG.getNode(Opc, dl, VT, N0, N1, N2);
  } else if (EVT == MVT::f32 && isa<ConstantSDNode>(N2)) {
    // Bits [7:6] of the constant are the source select.  This will always be
    //  zero here.  The DAG Combiner may combine an extract_elt index into these
    //  bits.  For example (insert (extract, 3), 2) could be matched by putting
    //  the '3' into bits [7:6] of X86ISD::INSERTPS.
    // Bits [5:4] of the constant are the destination select.  This is the
    //  value of the incoming immediate.
    // Bits [3:0] of the constant are the zero mask.  The DAG Combiner may
    //   combine either bitwise AND or insert of float 0.0 to set these bits.
    N2 = DAG.getIntPtrConstant(cast<ConstantSDNode>(N2)->getZExtValue() << 4);
    // Create this as a scalar to vector..
    N1 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v4f32, N1);
    return DAG.getNode(X86ISD::INSERTPS, dl, VT, N0, N1, N2);
  } else if (EVT == MVT::i32 && isa<ConstantSDNode>(N2)) {
    // PINSR* works with constant index.
    return Op;
  }
  return SDValue();
}

SDValue
X86TargetLowering::LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) {
  MVT VT = Op.getValueType();
  MVT EVT = VT.getVectorElementType();

  if (Subtarget->hasSSE41())
    return LowerINSERT_VECTOR_ELT_SSE4(Op, DAG);

  if (EVT == MVT::i8)
    return SDValue();

  DebugLoc dl = Op.getDebugLoc();
  SDValue N0 = Op.getOperand(0);
  SDValue N1 = Op.getOperand(1);
  SDValue N2 = Op.getOperand(2);

  if (EVT.getSizeInBits() == 16 && isa<ConstantSDNode>(N2)) {
    // Transform it so it match pinsrw which expects a 16-bit value in a GR32
    // as its second argument.
    if (N1.getValueType() != MVT::i32)
      N1 = DAG.getNode(ISD::ANY_EXTEND, dl, MVT::i32, N1);
    if (N2.getValueType() != MVT::i32)
      N2 = DAG.getIntPtrConstant(cast<ConstantSDNode>(N2)->getZExtValue());
    return DAG.getNode(X86ISD::PINSRW, dl, VT, N0, N1, N2);
  }
  return SDValue();
}

SDValue
X86TargetLowering::LowerSCALAR_TO_VECTOR(SDValue Op, SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();
  if (Op.getValueType() == MVT::v2f32)
    return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2f32,
                       DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2i32,
                                   DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i32,
                                               Op.getOperand(0))));

  if (Op.getValueType() == MVT::v1i64 && Op.getOperand(0).getValueType() == MVT::i64)
    return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v1i64, Op.getOperand(0));

  SDValue AnyExt = DAG.getNode(ISD::ANY_EXTEND, dl, MVT::i32, Op.getOperand(0));
  MVT VT = MVT::v2i32;
  switch (Op.getValueType().getSimpleVT()) {
  default: break;
  case MVT::v16i8:
  case MVT::v8i16:
    VT = MVT::v4i32;
    break;
  }
  return DAG.getNode(ISD::BIT_CONVERT, dl, Op.getValueType(),
                     DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, AnyExt));
}

// ConstantPool, JumpTable, GlobalAddress, and ExternalSymbol are lowered as
// their target countpart wrapped in the X86ISD::Wrapper node. Suppose N is
// one of the above mentioned nodes. It has to be wrapped because otherwise
// Select(N) returns N. So the raw TargetGlobalAddress nodes, etc. can only
// be used to form addressing mode. These wrapped nodes will be selected
// into MOV32ri.
SDValue
X86TargetLowering::LowerConstantPool(SDValue Op, SelectionDAG &DAG) {
  ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
  
  // In PIC mode (unless we're in RIPRel PIC mode) we add an offset to the
  // global base reg.
  unsigned char OpFlag = 0;
  unsigned WrapperKind = X86ISD::Wrapper;
  
  if (Subtarget->isPICStyleRIPRel() &&
      getTargetMachine().getCodeModel() == CodeModel::Small)
    WrapperKind = X86ISD::WrapperRIP;
  else if (Subtarget->isPICStyleGOT())
    OpFlag = X86II::MO_GOTOFF;
  else if (Subtarget->isPICStyleStubPIC())
    OpFlag = X86II::MO_PIC_BASE_OFFSET;
  
  SDValue Result = DAG.getTargetConstantPool(CP->getConstVal(), getPointerTy(),
                                             CP->getAlignment(),
                                             CP->getOffset(), OpFlag);
  DebugLoc DL = CP->getDebugLoc();
  Result = DAG.getNode(WrapperKind, DL, getPointerTy(), Result);
  // With PIC, the address is actually $g + Offset.
  if (OpFlag) {
    Result = DAG.getNode(ISD::ADD, DL, getPointerTy(),
                         DAG.getNode(X86ISD::GlobalBaseReg,
                                     DebugLoc::getUnknownLoc(), getPointerTy()),
                         Result);
  }

  return Result;
}

SDValue X86TargetLowering::LowerJumpTable(SDValue Op, SelectionDAG &DAG) {
  JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
  
  // In PIC mode (unless we're in RIPRel PIC mode) we add an offset to the
  // global base reg.
  unsigned char OpFlag = 0;
  unsigned WrapperKind = X86ISD::Wrapper;
  
  if (Subtarget->isPICStyleRIPRel() &&
      getTargetMachine().getCodeModel() == CodeModel::Small)
    WrapperKind = X86ISD::WrapperRIP;
  else if (Subtarget->isPICStyleGOT())
    OpFlag = X86II::MO_GOTOFF;
  else if (Subtarget->isPICStyleStubPIC())
    OpFlag = X86II::MO_PIC_BASE_OFFSET;
  
  SDValue Result = DAG.getTargetJumpTable(JT->getIndex(), getPointerTy(),
                                          OpFlag);
  DebugLoc DL = JT->getDebugLoc();
  Result = DAG.getNode(WrapperKind, DL, getPointerTy(), Result);
  
  // With PIC, the address is actually $g + Offset.
  if (OpFlag) {
    Result = DAG.getNode(ISD::ADD, DL, getPointerTy(),
                         DAG.getNode(X86ISD::GlobalBaseReg,
                                     DebugLoc::getUnknownLoc(), getPointerTy()),
                         Result);
  }
  
  return Result;
}

SDValue
X86TargetLowering::LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) {
  const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
  
  // In PIC mode (unless we're in RIPRel PIC mode) we add an offset to the
  // global base reg.
  unsigned char OpFlag = 0;
  unsigned WrapperKind = X86ISD::Wrapper;
  if (Subtarget->isPICStyleRIPRel() &&
      getTargetMachine().getCodeModel() == CodeModel::Small)
    WrapperKind = X86ISD::WrapperRIP;
  else if (Subtarget->isPICStyleGOT())
    OpFlag = X86II::MO_GOTOFF;
  else if (Subtarget->isPICStyleStubPIC())
    OpFlag = X86II::MO_PIC_BASE_OFFSET;
  
  SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy(), OpFlag);
  
  DebugLoc DL = Op.getDebugLoc();
  Result = DAG.getNode(WrapperKind, DL, getPointerTy(), Result);
  
  
  // With PIC, the address is actually $g + Offset.
  if (getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
      !Subtarget->is64Bit()) {
    Result = DAG.getNode(ISD::ADD, DL, getPointerTy(),
                         DAG.getNode(X86ISD::GlobalBaseReg,
                                     DebugLoc::getUnknownLoc(),
                                     getPointerTy()),
                         Result);
  }
  
  return Result;
}

SDValue
X86TargetLowering::LowerGlobalAddress(const GlobalValue *GV, DebugLoc dl,
                                      int64_t Offset,
                                      SelectionDAG &DAG) const {
  // Create the TargetGlobalAddress node, folding in the constant
  // offset if it is legal.
  unsigned char OpFlags =
    Subtarget->ClassifyGlobalReference(GV, getTargetMachine());
  SDValue Result;
  if (OpFlags == X86II::MO_NO_FLAG && isInt32(Offset)) {
    // A direct static reference to a global.
    Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset);
    Offset = 0;
  } else {
    Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), 0, OpFlags);
  }
  
  if (Subtarget->isPICStyleRIPRel() &&
      getTargetMachine().getCodeModel() == CodeModel::Small)
    Result = DAG.getNode(X86ISD::WrapperRIP, dl, getPointerTy(), Result);
  else
    Result = DAG.getNode(X86ISD::Wrapper, dl, getPointerTy(), Result);

  // With PIC, the address is actually $g + Offset.
  if (isGlobalRelativeToPICBase(OpFlags)) {
    Result = DAG.getNode(ISD::ADD, dl, getPointerTy(),
                         DAG.getNode(X86ISD::GlobalBaseReg, dl, getPointerTy()),
                         Result);
  }

  // For globals that require a load from a stub to get the address, emit the
  // load.
  if (isGlobalStubReference(OpFlags))
    Result = DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(), Result,
                         PseudoSourceValue::getGOT(), 0);

  // If there was a non-zero offset that we didn't fold, create an explicit
  // addition for it.
  if (Offset != 0)
    Result = DAG.getNode(ISD::ADD, dl, getPointerTy(), Result,
                         DAG.getConstant(Offset, getPointerTy()));

  return Result;
}

SDValue
X86TargetLowering::LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) {
  const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
  int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
  return LowerGlobalAddress(GV, Op.getDebugLoc(), Offset, DAG);
}

static SDValue
GetTLSADDR(SelectionDAG &DAG, SDValue Chain, GlobalAddressSDNode *GA,
           SDValue *InFlag, const MVT PtrVT, unsigned ReturnReg,
           unsigned char OperandFlags) {
  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
  DebugLoc dl = GA->getDebugLoc();
  SDValue TGA = DAG.getTargetGlobalAddress(GA->getGlobal(),
                                           GA->getValueType(0),
                                           GA->getOffset(),
                                           OperandFlags);
  if (InFlag) {
    SDValue Ops[] = { Chain,  TGA, *InFlag };
    Chain = DAG.getNode(X86ISD::TLSADDR, dl, NodeTys, Ops, 3);
  } else {
    SDValue Ops[]  = { Chain, TGA };
    Chain = DAG.getNode(X86ISD::TLSADDR, dl, NodeTys, Ops, 2);
  }
  SDValue Flag = Chain.getValue(1);
  return DAG.getCopyFromReg(Chain, dl, ReturnReg, PtrVT, Flag);
}

// Lower ISD::GlobalTLSAddress using the "general dynamic" model, 32 bit
static SDValue
LowerToTLSGeneralDynamicModel32(GlobalAddressSDNode *GA, SelectionDAG &DAG,
                                const MVT PtrVT) {
  SDValue InFlag;
  DebugLoc dl = GA->getDebugLoc();  // ? function entry point might be better
  SDValue Chain = DAG.getCopyToReg(DAG.getEntryNode(), dl, X86::EBX,
                                     DAG.getNode(X86ISD::GlobalBaseReg,
                                                 DebugLoc::getUnknownLoc(),
                                                 PtrVT), InFlag);
  InFlag = Chain.getValue(1);

  return GetTLSADDR(DAG, Chain, GA, &InFlag, PtrVT, X86::EAX, X86II::MO_TLSGD);
}

// Lower ISD::GlobalTLSAddress using the "general dynamic" model, 64 bit
static SDValue
LowerToTLSGeneralDynamicModel64(GlobalAddressSDNode *GA, SelectionDAG &DAG,
                                const MVT PtrVT) {
  return GetTLSADDR(DAG, DAG.getEntryNode(), GA, NULL, PtrVT,
                    X86::RAX, X86II::MO_TLSGD);
}

// Lower ISD::GlobalTLSAddress using the "initial exec" (for no-pic) or
// "local exec" model.
static SDValue LowerToTLSExecModel(GlobalAddressSDNode *GA, SelectionDAG &DAG,
                                   const MVT PtrVT, TLSModel::Model model,
                                   bool is64Bit) {
  DebugLoc dl = GA->getDebugLoc();
  // Get the Thread Pointer
  SDValue Base = DAG.getNode(X86ISD::SegmentBaseAddress,
                             DebugLoc::getUnknownLoc(), PtrVT,
                             DAG.getRegister(is64Bit? X86::FS : X86::GS,
                                             MVT::i32));

  SDValue ThreadPointer = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), Base,
                                      NULL, 0);

  unsigned char OperandFlags = 0;
  // Most TLS accesses are not RIP relative, even on x86-64.  One exception is
  // initialexec.
  unsigned WrapperKind = X86ISD::Wrapper;
  if (model == TLSModel::LocalExec) {
    OperandFlags = is64Bit ? X86II::MO_TPOFF : X86II::MO_NTPOFF;
  } else if (is64Bit) {
    assert(model == TLSModel::InitialExec);
    OperandFlags = X86II::MO_GOTTPOFF;
    WrapperKind = X86ISD::WrapperRIP;
  } else {
    assert(model == TLSModel::InitialExec);
    OperandFlags = X86II::MO_INDNTPOFF;
  }
  
  // emit "addl x@ntpoff,%eax" (local exec) or "addl x@indntpoff,%eax" (initial
  // exec)
  SDValue TGA = DAG.getTargetGlobalAddress(GA->getGlobal(), GA->getValueType(0),
                                           GA->getOffset(), OperandFlags);
  SDValue Offset = DAG.getNode(WrapperKind, dl, PtrVT, TGA);

  if (model == TLSModel::InitialExec)
    Offset = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), Offset,
                         PseudoSourceValue::getGOT(), 0);

  // The address of the thread local variable is the add of the thread
  // pointer with the offset of the variable.
  return DAG.getNode(ISD::ADD, dl, PtrVT, ThreadPointer, Offset);
}

SDValue
X86TargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) {
  // TODO: implement the "local dynamic" model
  // TODO: implement the "initial exec"model for pic executables
  assert(Subtarget->isTargetELF() &&
         "TLS not implemented for non-ELF targets");
  GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
  const GlobalValue *GV = GA->getGlobal();
  
  // If GV is an alias then use the aliasee for determining
  // thread-localness.
  if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
    GV = GA->resolveAliasedGlobal(false);
  
  TLSModel::Model model = getTLSModel(GV,
                                      getTargetMachine().getRelocationModel());
  
  switch (model) {
  case TLSModel::GeneralDynamic:
  case TLSModel::LocalDynamic: // not implemented
    if (Subtarget->is64Bit())
      return LowerToTLSGeneralDynamicModel64(GA, DAG, getPointerTy());
    return LowerToTLSGeneralDynamicModel32(GA, DAG, getPointerTy());
    
  case TLSModel::InitialExec:
  case TLSModel::LocalExec:
    return LowerToTLSExecModel(GA, DAG, getPointerTy(), model,
                               Subtarget->is64Bit());
  }
  
  llvm_unreachable("Unreachable");
  return SDValue();
}


/// LowerShift - Lower SRA_PARTS and friends, which return two i32 values and
/// take a 2 x i32 value to shift plus a shift amount.
SDValue X86TargetLowering::LowerShift(SDValue Op, SelectionDAG &DAG) {
  assert(Op.getNumOperands() == 3 && "Not a double-shift!");
  MVT VT = Op.getValueType();
  unsigned VTBits = VT.getSizeInBits();
  DebugLoc dl = Op.getDebugLoc();
  bool isSRA = Op.getOpcode() == ISD::SRA_PARTS;
  SDValue ShOpLo = Op.getOperand(0);
  SDValue ShOpHi = Op.getOperand(1);
  SDValue ShAmt  = Op.getOperand(2);
  SDValue Tmp1 = isSRA ? DAG.getNode(ISD::SRA, dl, VT, ShOpHi,
                                     DAG.getConstant(VTBits - 1, MVT::i8))
                       : DAG.getConstant(0, VT);

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

  SDValue AndNode = DAG.getNode(ISD::AND, dl, MVT::i8, ShAmt,
                                DAG.getConstant(VTBits, MVT::i8));
  SDValue Cond = DAG.getNode(X86ISD::CMP, dl, VT,
                             AndNode, DAG.getConstant(0, MVT::i8));

  SDValue Hi, Lo;
  SDValue CC = DAG.getConstant(X86::COND_NE, MVT::i8);
  SDValue Ops0[4] = { Tmp2, Tmp3, CC, Cond };
  SDValue Ops1[4] = { Tmp3, Tmp1, CC, Cond };

  if (Op.getOpcode() == ISD::SHL_PARTS) {
    Hi = DAG.getNode(X86ISD::CMOV, dl, VT, Ops0, 4);
    Lo = DAG.getNode(X86ISD::CMOV, dl, VT, Ops1, 4);
  } else {
    Lo = DAG.getNode(X86ISD::CMOV, dl, VT, Ops0, 4);
    Hi = DAG.getNode(X86ISD::CMOV, dl, VT, Ops1, 4);
  }

  SDValue Ops[2] = { Lo, Hi };
  return DAG.getMergeValues(Ops, 2, dl);
}

SDValue X86TargetLowering::LowerSINT_TO_FP(SDValue Op, SelectionDAG &DAG) {
  MVT SrcVT = Op.getOperand(0).getValueType();

  if (SrcVT.isVector()) {
    if (SrcVT == MVT::v2i32 && Op.getValueType() == MVT::v2f64) {
      return Op;
    }
    return SDValue();
  }

  assert(SrcVT.getSimpleVT() <= MVT::i64 && SrcVT.getSimpleVT() >= MVT::i16 &&
         "Unknown SINT_TO_FP to lower!");

  // These are really Legal; return the operand so the caller accepts it as
  // Legal.
  if (SrcVT == MVT::i32 && isScalarFPTypeInSSEReg(Op.getValueType()))
    return Op;
  if (SrcVT == MVT::i64 && isScalarFPTypeInSSEReg(Op.getValueType()) &&
      Subtarget->is64Bit()) {
    return Op;
  }

  DebugLoc dl = Op.getDebugLoc();
  unsigned Size = SrcVT.getSizeInBits()/8;
  MachineFunction &MF = DAG.getMachineFunction();
  int SSFI = MF.getFrameInfo()->CreateStackObject(Size, Size);
  SDValue StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
  SDValue Chain = DAG.getStore(DAG.getEntryNode(), dl, Op.getOperand(0),
                               StackSlot,
                               PseudoSourceValue::getFixedStack(SSFI), 0);
  return BuildFILD(Op, SrcVT, Chain, StackSlot, DAG);
}

SDValue X86TargetLowering::BuildFILD(SDValue Op, MVT SrcVT, SDValue Chain,
                                     SDValue StackSlot,
                                     SelectionDAG &DAG) {
  // Build the FILD
  DebugLoc dl = Op.getDebugLoc();
  SDVTList Tys;
  bool useSSE = isScalarFPTypeInSSEReg(Op.getValueType());
  if (useSSE)
    Tys = DAG.getVTList(MVT::f64, MVT::Other, MVT::Flag);
  else
    Tys = DAG.getVTList(Op.getValueType(), MVT::Other);
  SmallVector<SDValue, 8> Ops;
  Ops.push_back(Chain);
  Ops.push_back(StackSlot);
  Ops.push_back(DAG.getValueType(SrcVT));
  SDValue Result = DAG.getNode(useSSE ? X86ISD::FILD_FLAG : X86ISD::FILD, dl,
                                 Tys, &Ops[0], Ops.size());

  if (useSSE) {
    Chain = Result.getValue(1);
    SDValue InFlag = Result.getValue(2);

    // FIXME: Currently the FST is flagged to the FILD_FLAG. This
    // shouldn't be necessary except that RFP cannot be live across
    // multiple blocks. When stackifier is fixed, they can be uncoupled.
    MachineFunction &MF = DAG.getMachineFunction();
    int SSFI = MF.getFrameInfo()->CreateStackObject(8, 8);
    SDValue StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
    Tys = DAG.getVTList(MVT::Other);
    SmallVector<SDValue, 8> Ops;
    Ops.push_back(Chain);
    Ops.push_back(Result);
    Ops.push_back(StackSlot);
    Ops.push_back(DAG.getValueType(Op.getValueType()));
    Ops.push_back(InFlag);
    Chain = DAG.getNode(X86ISD::FST, dl, Tys, &Ops[0], Ops.size());
    Result = DAG.getLoad(Op.getValueType(), dl, Chain, StackSlot,
                         PseudoSourceValue::getFixedStack(SSFI), 0);
  }

  return Result;
}

// LowerUINT_TO_FP_i64 - 64-bit unsigned integer to double expansion.
SDValue X86TargetLowering::LowerUINT_TO_FP_i64(SDValue Op, SelectionDAG &DAG) {
  // This algorithm is not obvious. Here it is in C code, more or less:
  /*
    double uint64_to_double( uint32_t hi, uint32_t lo ) {
      static const __m128i exp = { 0x4330000045300000ULL, 0 };
      static const __m128d bias = { 0x1.0p84, 0x1.0p52 };

      // Copy ints to xmm registers.
      __m128i xh = _mm_cvtsi32_si128( hi );
      __m128i xl = _mm_cvtsi32_si128( lo );

      // Combine into low half of a single xmm register.
      __m128i x = _mm_unpacklo_epi32( xh, xl );
      __m128d d;
      double sd;

      // Merge in appropriate exponents to give the integer bits the right
      // magnitude.
      x = _mm_unpacklo_epi32( x, exp );

      // Subtract away the biases to deal with the IEEE-754 double precision
      // implicit 1.
      d = _mm_sub_pd( (__m128d) x, bias );

      // All conversions up to here are exact. The correctly rounded result is
      // calculated using the current rounding mode using the following
      // horizontal add.
      d = _mm_add_sd( d, _mm_unpackhi_pd( d, d ) );
      _mm_store_sd( &sd, d );   // Because we are returning doubles in XMM, this
                                // store doesn't really need to be here (except
                                // maybe to zero the other double)
      return sd;
    }
  */

  DebugLoc dl = Op.getDebugLoc();
  LLVMContext *Context = DAG.getContext();

  // Build some magic constants.
  std::vector<Constant*> CV0;
  CV0.push_back(ConstantInt::get(*Context, APInt(32, 0x45300000)));
  CV0.push_back(ConstantInt::get(*Context, APInt(32, 0x43300000)));
  CV0.push_back(ConstantInt::get(*Context, APInt(32, 0)));
  CV0.push_back(ConstantInt::get(*Context, APInt(32, 0)));
  Constant *C0 = ConstantVector::get(CV0);
  SDValue CPIdx0 = DAG.getConstantPool(C0, getPointerTy(), 16);

  std::vector<Constant*> CV1;
  CV1.push_back(
    ConstantFP::get(*Context, APFloat(APInt(64, 0x4530000000000000ULL))));
  CV1.push_back(
    ConstantFP::get(*Context, APFloat(APInt(64, 0x4330000000000000ULL))));
  Constant *C1 = ConstantVector::get(CV1);
  SDValue CPIdx1 = DAG.getConstantPool(C1, getPointerTy(), 16);

  SDValue XR1 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v4i32,
                            DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
                                        Op.getOperand(0),
                                        DAG.getIntPtrConstant(1)));
  SDValue XR2 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v4i32,
                            DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
                                        Op.getOperand(0),
                                        DAG.getIntPtrConstant(0)));
  SDValue Unpck1 = getUnpackl(DAG, dl, MVT::v4i32, XR1, XR2);
  SDValue CLod0 = DAG.getLoad(MVT::v4i32, dl, DAG.getEntryNode(), CPIdx0,
                              PseudoSourceValue::getConstantPool(), 0,
                              false, 16);
  SDValue Unpck2 = getUnpackl(DAG, dl, MVT::v4i32, Unpck1, CLod0);
  SDValue XR2F = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2f64, Unpck2);
  SDValue CLod1 = DAG.getLoad(MVT::v2f64, dl, CLod0.getValue(1), CPIdx1,
                              PseudoSourceValue::getConstantPool(), 0,
                              false, 16);
  SDValue Sub = DAG.getNode(ISD::FSUB, dl, MVT::v2f64, XR2F, CLod1);

  // Add the halves; easiest way is to swap them into another reg first.
  int ShufMask[2] = { 1, -1 };
  SDValue Shuf = DAG.getVectorShuffle(MVT::v2f64, dl, Sub,
                                      DAG.getUNDEF(MVT::v2f64), ShufMask);
  SDValue Add = DAG.getNode(ISD::FADD, dl, MVT::v2f64, Shuf, Sub);
  return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::f64, Add,
                     DAG.getIntPtrConstant(0));
}

// LowerUINT_TO_FP_i32 - 32-bit unsigned integer to float expansion.
SDValue X86TargetLowering::LowerUINT_TO_FP_i32(SDValue Op, SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();
  // FP constant to bias correct the final result.
  SDValue Bias = DAG.getConstantFP(BitsToDouble(0x4330000000000000ULL),
                                   MVT::f64);

  // Load the 32-bit value into an XMM register.
  SDValue Load = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v4i32,
                             DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
                                         Op.getOperand(0),
                                         DAG.getIntPtrConstant(0)));

  Load = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::f64,
                     DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2f64, Load),
                     DAG.getIntPtrConstant(0));

  // Or the load with the bias.
  SDValue Or = DAG.getNode(ISD::OR, dl, MVT::v2i64,
                           DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64,
                                       DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
                                                   MVT::v2f64, Load)),
                           DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64,
                                       DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
                                                   MVT::v2f64, Bias)));
  Or = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::f64,
                   DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2f64, Or),
                   DAG.getIntPtrConstant(0));

  // Subtract the bias.
  SDValue Sub = DAG.getNode(ISD::FSUB, dl, MVT::f64, Or, Bias);

  // Handle final rounding.
  MVT DestVT = Op.getValueType();

  if (DestVT.bitsLT(MVT::f64)) {
    return DAG.getNode(ISD::FP_ROUND, dl, DestVT, Sub,
                       DAG.getIntPtrConstant(0));
  } else if (DestVT.bitsGT(MVT::f64)) {
    return DAG.getNode(ISD::FP_EXTEND, dl, DestVT, Sub);
  }

  // Handle final rounding.
  return Sub;
}

SDValue X86TargetLowering::LowerUINT_TO_FP(SDValue Op, SelectionDAG &DAG) {
  SDValue N0 = Op.getOperand(0);
  DebugLoc dl = Op.getDebugLoc();

  // Now not UINT_TO_FP is legal (it's marked custom), dag combiner won't
  // optimize it to a SINT_TO_FP when the sign bit is known zero. Perform
  // the optimization here.
  if (DAG.SignBitIsZero(N0))
    return DAG.getNode(ISD::SINT_TO_FP, dl, Op.getValueType(), N0);

  MVT SrcVT = N0.getValueType();
  if (SrcVT == MVT::i64) {
    // We only handle SSE2 f64 target here; caller can expand the rest.
    if (Op.getValueType() != MVT::f64 || !X86ScalarSSEf64)
      return SDValue();

    return LowerUINT_TO_FP_i64(Op, DAG);
  } else if (SrcVT == MVT::i32 && X86ScalarSSEf64) {
    return LowerUINT_TO_FP_i32(Op, DAG);
  }

  assert(SrcVT == MVT::i32 && "Unknown UINT_TO_FP to lower!");

  // Make a 64-bit buffer, and use it to build an FILD.
  SDValue StackSlot = DAG.CreateStackTemporary(MVT::i64);
  SDValue WordOff = DAG.getConstant(4, getPointerTy());
  SDValue OffsetSlot = DAG.getNode(ISD::ADD, dl,
                                   getPointerTy(), StackSlot, WordOff);
  SDValue Store1 = DAG.getStore(DAG.getEntryNode(), dl, Op.getOperand(0),
                                StackSlot, NULL, 0);
  SDValue Store2 = DAG.getStore(Store1, dl, DAG.getConstant(0, MVT::i32),
                                OffsetSlot, NULL, 0);
  return BuildFILD(Op, MVT::i64, Store2, StackSlot, DAG);
}

std::pair<SDValue,SDValue> X86TargetLowering::
FP_TO_INTHelper(SDValue Op, SelectionDAG &DAG, bool IsSigned) {
  DebugLoc dl = Op.getDebugLoc();

  MVT DstTy = Op.getValueType();

  if (!IsSigned) {
    assert(DstTy == MVT::i32 && "Unexpected FP_TO_UINT");
    DstTy = MVT::i64;
  }

  assert(DstTy.getSimpleVT() <= MVT::i64 &&
         DstTy.getSimpleVT() >= MVT::i16 &&
         "Unknown FP_TO_SINT to lower!");

  // These are really Legal.
  if (DstTy == MVT::i32 &&
      isScalarFPTypeInSSEReg(Op.getOperand(0).getValueType()))
    return std::make_pair(SDValue(), SDValue());
  if (Subtarget->is64Bit() &&
      DstTy == MVT::i64 &&
      isScalarFPTypeInSSEReg(Op.getOperand(0).getValueType()))
    return std::make_pair(SDValue(), SDValue());

  // We lower FP->sint64 into FISTP64, followed by a load, all to a temporary
  // stack slot.
  MachineFunction &MF = DAG.getMachineFunction();
  unsigned MemSize = DstTy.getSizeInBits()/8;
  int SSFI = MF.getFrameInfo()->CreateStackObject(MemSize, MemSize);
  SDValue StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
  
  unsigned Opc;
  switch (DstTy.getSimpleVT()) {
  default: llvm_unreachable("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;
  }

  SDValue Chain = DAG.getEntryNode();
  SDValue Value = Op.getOperand(0);
  if (isScalarFPTypeInSSEReg(Op.getOperand(0).getValueType())) {
    assert(DstTy == MVT::i64 && "Invalid FP_TO_SINT to lower!");
    Chain = DAG.getStore(Chain, dl, Value, StackSlot,
                         PseudoSourceValue::getFixedStack(SSFI), 0);
    SDVTList Tys = DAG.getVTList(Op.getOperand(0).getValueType(), MVT::Other);
    SDValue Ops[] = {
      Chain, StackSlot, DAG.getValueType(Op.getOperand(0).getValueType())
    };
    Value = DAG.getNode(X86ISD::FLD, dl, Tys, Ops, 3);
    Chain = Value.getValue(1);
    SSFI = MF.getFrameInfo()->CreateStackObject(MemSize, MemSize);
    StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
  }

  // Build the FP_TO_INT*_IN_MEM
  SDValue Ops[] = { Chain, Value, StackSlot };
  SDValue FIST = DAG.getNode(Opc, dl, MVT::Other, Ops, 3);

  return std::make_pair(FIST, StackSlot);
}

SDValue X86TargetLowering::LowerFP_TO_SINT(SDValue Op, SelectionDAG &DAG) {
  if (Op.getValueType().isVector()) {
    if (Op.getValueType() == MVT::v2i32 &&
        Op.getOperand(0).getValueType() == MVT::v2f64) {
      return Op;
    }
    return SDValue();
  }

  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG, true);
  SDValue FIST = Vals.first, StackSlot = Vals.second;
  // If FP_TO_INTHelper failed, the node is actually supposed to be Legal.
  if (FIST.getNode() == 0) return Op;

  // Load the result.
  return DAG.getLoad(Op.getValueType(), Op.getDebugLoc(),
                     FIST, StackSlot, NULL, 0);
}

SDValue X86TargetLowering::LowerFP_TO_UINT(SDValue Op, SelectionDAG &DAG) {
  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG, false);
  SDValue FIST = Vals.first, StackSlot = Vals.second;
  assert(FIST.getNode() && "Unexpected failure");

  // Load the result.
  return DAG.getLoad(Op.getValueType(), Op.getDebugLoc(),
                     FIST, StackSlot, NULL, 0);
}

SDValue X86TargetLowering::LowerFABS(SDValue Op, SelectionDAG &DAG) {
  LLVMContext *Context = DAG.getContext();
  DebugLoc dl = Op.getDebugLoc();
  MVT VT = Op.getValueType();
  MVT EltVT = VT;
  if (VT.isVector())
    EltVT = VT.getVectorElementType();
  std::vector<Constant*> CV;
  if (EltVT == MVT::f64) {
    Constant *C = ConstantFP::get(*Context, APFloat(APInt(64, ~(1ULL << 63))));
    CV.push_back(C);
    CV.push_back(C);
  } else {
    Constant *C = ConstantFP::get(*Context, APFloat(APInt(32, ~(1U << 31))));
    CV.push_back(C);
    CV.push_back(C);
    CV.push_back(C);
    CV.push_back(C);
  }
  Constant *C = ConstantVector::get(CV);
  SDValue CPIdx = DAG.getConstantPool(C, getPointerTy(), 16);
  SDValue Mask = DAG.getLoad(VT, dl, DAG.getEntryNode(), CPIdx,
                               PseudoSourceValue::getConstantPool(), 0,
                               false, 16);
  return DAG.getNode(X86ISD::FAND, dl, VT, Op.getOperand(0), Mask);
}

SDValue X86TargetLowering::LowerFNEG(SDValue Op, SelectionDAG &DAG) {
  LLVMContext *Context = DAG.getContext();
  DebugLoc dl = Op.getDebugLoc();
  MVT VT = Op.getValueType();
  MVT EltVT = VT;
  unsigned EltNum = 1;
  if (VT.isVector()) {
    EltVT = VT.getVectorElementType();
    EltNum = VT.getVectorNumElements();
  }
  std::vector<Constant*> CV;
  if (EltVT == MVT::f64) {
    Constant *C = ConstantFP::get(*Context, APFloat(APInt(64, 1ULL << 63)));
    CV.push_back(C);
    CV.push_back(C);
  } else {
    Constant *C = ConstantFP::get(*Context, APFloat(APInt(32, 1U << 31)));
    CV.push_back(C);
    CV.push_back(C);
    CV.push_back(C);
    CV.push_back(C);
  }
  Constant *C = ConstantVector::get(CV);
  SDValue CPIdx = DAG.getConstantPool(C, getPointerTy(), 16);
  SDValue Mask = DAG.getLoad(VT, dl, DAG.getEntryNode(), CPIdx,
                               PseudoSourceValue::getConstantPool(), 0,
                               false, 16);
  if (VT.isVector()) {
    return DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                       DAG.getNode(ISD::XOR, dl, MVT::v2i64,
                    DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64,
                                Op.getOperand(0)),
                    DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v2i64, Mask)));
  } else {
    return DAG.getNode(X86ISD::FXOR, dl, VT, Op.getOperand(0), Mask);
  }
}

SDValue X86TargetLowering::LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) {
  LLVMContext *Context = DAG.getContext();
  SDValue Op0 = Op.getOperand(0);
  SDValue Op1 = Op.getOperand(1);
  DebugLoc dl = Op.getDebugLoc();
  MVT VT = Op.getValueType();
  MVT SrcVT = Op1.getValueType();

  // If second operand is smaller, extend it first.
  if (SrcVT.bitsLT(VT)) {
    Op1 = DAG.getNode(ISD::FP_EXTEND, dl, VT, Op1);
    SrcVT = VT;
  }
  // And if it is bigger, shrink it first.
  if (SrcVT.bitsGT(VT)) {
    Op1 = DAG.getNode(ISD::FP_ROUND, dl, VT, Op1, DAG.getIntPtrConstant(1));
    SrcVT = VT;
  }

  // At this point the operands and the result should have the same
  // type, and that won't be f80 since that is not custom lowered.

  // First get the sign bit of second operand.
  std::vector<Constant*> CV;
  if (SrcVT == MVT::f64) {
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(64, 1ULL << 63))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(64, 0))));
  } else {
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 1U << 31))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
  }
  Constant *C = ConstantVector::get(CV);
  SDValue CPIdx = DAG.getConstantPool(C, getPointerTy(), 16);
  SDValue Mask1 = DAG.getLoad(SrcVT, dl, DAG.getEntryNode(), CPIdx,
                                PseudoSourceValue::getConstantPool(), 0,
                                false, 16);
  SDValue SignBit = DAG.getNode(X86ISD::FAND, dl, SrcVT, Op1, Mask1);

  // Shift sign bit right or left if the two operands have different types.
  if (SrcVT.bitsGT(VT)) {
    // Op0 is MVT::f32, Op1 is MVT::f64.
    SignBit = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2f64, SignBit);
    SignBit = DAG.getNode(X86ISD::FSRL, dl, MVT::v2f64, SignBit,
                          DAG.getConstant(32, MVT::i32));
    SignBit = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v4f32, SignBit);
    SignBit = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::f32, SignBit,
                          DAG.getIntPtrConstant(0));
  }

  // Clear first operand sign bit.
  CV.clear();
  if (VT == MVT::f64) {
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(64, ~(1ULL << 63)))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(64, 0))));
  } else {
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, ~(1U << 31)))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
    CV.push_back(ConstantFP::get(*Context, APFloat(APInt(32, 0))));
  }
  C = ConstantVector::get(CV);
  CPIdx = DAG.getConstantPool(C, getPointerTy(), 16);
  SDValue Mask2 = DAG.getLoad(VT, dl, DAG.getEntryNode(), CPIdx,
                                PseudoSourceValue::getConstantPool(), 0,
                                false, 16);
  SDValue Val = DAG.getNode(X86ISD::FAND, dl, VT, Op0, Mask2);

  // Or the value with the sign bit.
  return DAG.getNode(X86ISD::FOR, dl, VT, Val, SignBit);
}

/// Emit nodes that will be selected as "test Op0,Op0", or something
/// equivalent.
SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC,
                                    SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();

  // CF and OF aren't always set the way we want. Determine which
  // of these we need.
  bool NeedCF = false;
  bool NeedOF = false;
  switch (X86CC) {
  case X86::COND_A: case X86::COND_AE:
  case X86::COND_B: case X86::COND_BE:
    NeedCF = true;
    break;
  case X86::COND_G: case X86::COND_GE:
  case X86::COND_L: case X86::COND_LE:
  case X86::COND_O: case X86::COND_NO:
    NeedOF = true;
    break;
  default: break;
  }

  // See if we can use the EFLAGS value from the operand instead of
  // doing a separate TEST. TEST always sets OF and CF to 0, so unless
  // we prove that the arithmetic won't overflow, we can't use OF or CF.
  if (Op.getResNo() == 0 && !NeedOF && !NeedCF) {
    unsigned Opcode = 0;
    unsigned NumOperands = 0;
    switch (Op.getNode()->getOpcode()) {
    case ISD::ADD:
      // Due to an isel shortcoming, be conservative if this add is likely to
      // be selected as part of a load-modify-store instruction. When the root
      // node in a match is a store, isel doesn't know how to remap non-chain
      // non-flag uses of other nodes in the match, such as the ADD in this
      // case. This leads to the ADD being left around and reselected, with
      // the result being two adds in the output.
      for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
           UE = Op.getNode()->use_end(); UI != UE; ++UI)
        if (UI->getOpcode() == ISD::STORE)
          goto default_case;
      if (ConstantSDNode *C =
            dyn_cast<ConstantSDNode>(Op.getNode()->getOperand(1))) {
        // An add of one will be selected as an INC.
        if (C->getAPIntValue() == 1) {
          Opcode = X86ISD::INC;
          NumOperands = 1;
          break;
        }
        // An add of negative one (subtract of one) will be selected as a DEC.
        if (C->getAPIntValue().isAllOnesValue()) {
          Opcode = X86ISD::DEC;
          NumOperands = 1;
          break;
        }
      }
      // Otherwise use a regular EFLAGS-setting add.
      Opcode = X86ISD::ADD;
      NumOperands = 2;
      break;
    case ISD::SUB:
      // Due to the ISEL shortcoming noted above, be conservative if this sub is
      // likely to be selected as part of a load-modify-store instruction.
      for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
           UE = Op.getNode()->use_end(); UI != UE; ++UI)
        if (UI->getOpcode() == ISD::STORE)
          goto default_case;
      // Otherwise use a regular EFLAGS-setting sub.
      Opcode = X86ISD::SUB;
      NumOperands = 2;
      break;
    case X86ISD::ADD:
    case X86ISD::SUB:
    case X86ISD::INC:
    case X86ISD::DEC:
      return SDValue(Op.getNode(), 1);
    default:
    default_case:
      break;
    }
    if (Opcode != 0) {
      SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::i32);
      SmallVector<SDValue, 4> Ops;
      for (unsigned i = 0; i != NumOperands; ++i)
        Ops.push_back(Op.getOperand(i));
      SDValue New = DAG.getNode(Opcode, dl, VTs, &Ops[0], NumOperands);
      DAG.ReplaceAllUsesWith(Op, New);
      return SDValue(New.getNode(), 1);
    }
  }

  // Otherwise just emit a CMP with 0, which is the TEST pattern.
  return DAG.getNode(X86ISD::CMP, dl, MVT::i32, Op,
                     DAG.getConstant(0, Op.getValueType()));
}

/// Emit nodes that will be selected as "cmp Op0,Op1", or something
/// equivalent.
SDValue X86TargetLowering::EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC,
                                   SelectionDAG &DAG) {
  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op1))
    if (C->getAPIntValue() == 0)
      return EmitTest(Op0, X86CC, DAG);

  DebugLoc dl = Op0.getDebugLoc();
  return DAG.getNode(X86ISD::CMP, dl, MVT::i32, Op0, Op1);
}

SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) {
  assert(Op.getValueType() == MVT::i8 && "SetCC type must be 8-bit integer");
  SDValue Op0 = Op.getOperand(0);
  SDValue Op1 = Op.getOperand(1);
  DebugLoc dl = Op.getDebugLoc();
  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();

  // Lower (X & (1 << N)) == 0 to BT(X, N).
  // Lower ((X >>u N) & 1) != 0 to BT(X, N).
  // Lower ((X >>s N) & 1) != 0 to BT(X, N).
  if (Op0.getOpcode() == ISD::AND &&
      Op0.hasOneUse() &&
      Op1.getOpcode() == ISD::Constant &&
      cast<ConstantSDNode>(Op1)->getZExtValue() == 0 &&
      (CC == ISD::SETEQ || CC == ISD::SETNE)) {
    SDValue LHS, RHS;
    if (Op0.getOperand(1).getOpcode() == ISD::SHL) {
      if (ConstantSDNode *Op010C =
            dyn_cast<ConstantSDNode>(Op0.getOperand(1).getOperand(0)))
        if (Op010C->getZExtValue() == 1) {
          LHS = Op0.getOperand(0);
          RHS = Op0.getOperand(1).getOperand(1);
        }
    } else if (Op0.getOperand(0).getOpcode() == ISD::SHL) {
      if (ConstantSDNode *Op000C =
            dyn_cast<ConstantSDNode>(Op0.getOperand(0).getOperand(0)))
        if (Op000C->getZExtValue() == 1) {
          LHS = Op0.getOperand(1);
          RHS = Op0.getOperand(0).getOperand(1);
        }
    } else if (Op0.getOperand(1).getOpcode() == ISD::Constant) {
      ConstantSDNode *AndRHS = cast<ConstantSDNode>(Op0.getOperand(1));
      SDValue AndLHS = Op0.getOperand(0);
      if (AndRHS->getZExtValue() == 1 && AndLHS.getOpcode() == ISD::SRL) {
        LHS = AndLHS.getOperand(0);
        RHS = AndLHS.getOperand(1);
      }
    }

    if (LHS.getNode()) {
      // If LHS is i8, promote it to i16 with any_extend.  There is no i8 BT
      // instruction.  Since the shift amount is in-range-or-undefined, we know
      // that doing a bittest on the i16 value is ok.  We extend to i32 because
      // the encoding for the i16 version is larger than the i32 version.
      if (LHS.getValueType() == MVT::i8)
        LHS = DAG.getNode(ISD::ANY_EXTEND, dl, MVT::i32, LHS);

      // If the operand types disagree, extend the shift amount to match.  Since
      // BT ignores high bits (like shifts) we can use anyextend.
      if (LHS.getValueType() != RHS.getValueType())
        RHS = DAG.getNode(ISD::ANY_EXTEND, dl, LHS.getValueType(), RHS);

      SDValue BT = DAG.getNode(X86ISD::BT, dl, MVT::i32, LHS, RHS);
      unsigned Cond = CC == ISD::SETEQ ? X86::COND_AE : X86::COND_B;
      return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
                         DAG.getConstant(Cond, MVT::i8), BT);
    }
  }

  bool isFP = Op.getOperand(1).getValueType().isFloatingPoint();
  unsigned X86CC = TranslateX86CC(CC, isFP, Op0, Op1, DAG);

  SDValue Cond = EmitCmp(Op0, Op1, X86CC, DAG);
  return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
                     DAG.getConstant(X86CC, MVT::i8), Cond);
}

SDValue X86TargetLowering::LowerVSETCC(SDValue Op, SelectionDAG &DAG) {
  SDValue Cond;
  SDValue Op0 = Op.getOperand(0);
  SDValue Op1 = Op.getOperand(1);
  SDValue CC = Op.getOperand(2);
  MVT VT = Op.getValueType();
  ISD::CondCode SetCCOpcode = cast<CondCodeSDNode>(CC)->get();
  bool isFP = Op.getOperand(1).getValueType().isFloatingPoint();
  DebugLoc dl = Op.getDebugLoc();

  if (isFP) {
    unsigned SSECC = 8;
    MVT VT0 = Op0.getValueType();
    assert(VT0 == MVT::v4f32 || VT0 == MVT::v2f64);
    unsigned Opc = VT0 == MVT::v4f32 ? X86ISD::CMPPS : X86ISD::CMPPD;
    bool Swap = false;

    switch (SetCCOpcode) {
    default: break;
    case ISD::SETOEQ:
    case ISD::SETEQ:  SSECC = 0; break;
    case ISD::SETOGT:
    case ISD::SETGT: Swap = true; // Fallthrough
    case ISD::SETLT:
    case ISD::SETOLT: SSECC = 1; break;
    case ISD::SETOGE:
    case ISD::SETGE: Swap = true; // Fallthrough
    case ISD::SETLE:
    case ISD::SETOLE: SSECC = 2; break;
    case ISD::SETUO:  SSECC = 3; break;
    case ISD::SETUNE:
    case ISD::SETNE:  SSECC = 4; break;
    case ISD::SETULE: Swap = true;
    case ISD::SETUGE: SSECC = 5; break;
    case ISD::SETULT: Swap = true;
    case ISD::SETUGT: SSECC = 6; break;
    case ISD::SETO:   SSECC = 7; break;
    }
    if (Swap)
      std::swap(Op0, Op1);

    // In the two special cases we can't handle, emit two comparisons.
    if (SSECC == 8) {
      if (SetCCOpcode == ISD::SETUEQ) {
        SDValue UNORD, EQ;
        UNORD = DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(3, MVT::i8));
        EQ = DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(0, MVT::i8));
        return DAG.getNode(ISD::OR, dl, VT, UNORD, EQ);
      }
      else if (SetCCOpcode == ISD::SETONE) {
        SDValue ORD, NEQ;
        ORD = DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(7, MVT::i8));
        NEQ = DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(4, MVT::i8));
        return DAG.getNode(ISD::AND, dl, VT, ORD, NEQ);
      }
      llvm_unreachable("Illegal FP comparison");
    }
    // Handle all other FP comparisons here.
    return DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(SSECC, MVT::i8));
  }

  // We are handling one of the integer comparisons here.  Since SSE only has
  // GT and EQ comparisons for integer, swapping operands and multiple
  // operations may be required for some comparisons.
  unsigned Opc = 0, EQOpc = 0, GTOpc = 0;
  bool Swap = false, Invert = false, FlipSigns = false;

  switch (VT.getSimpleVT()) {
  default: break;
  case MVT::v8i8:
  case MVT::v16i8: EQOpc = X86ISD::PCMPEQB; GTOpc = X86ISD::PCMPGTB; break;
  case MVT::v4i16:
  case MVT::v8i16: EQOpc = X86ISD::PCMPEQW; GTOpc = X86ISD::PCMPGTW; break;
  case MVT::v2i32:
  case MVT::v4i32: EQOpc = X86ISD::PCMPEQD; GTOpc = X86ISD::PCMPGTD; break;
  case MVT::v2i64: EQOpc = X86ISD::PCMPEQQ; GTOpc = X86ISD::PCMPGTQ; break;
  }

  switch (SetCCOpcode) {
  default: break;
  case ISD::SETNE:  Invert = true;
  case ISD::SETEQ:  Opc = EQOpc; break;
  case ISD::SETLT:  Swap = true;
  case ISD::SETGT:  Opc = GTOpc; break;
  case ISD::SETGE:  Swap = true;
  case ISD::SETLE:  Opc = GTOpc; Invert = true; break;
  case ISD::SETULT: Swap = true;
  case ISD::SETUGT: Opc = GTOpc; FlipSigns = true; break;
  case ISD::SETUGE: Swap = true;
  case ISD::SETULE: Opc = GTOpc; FlipSigns = true; Invert = true; break;
  }
  if (Swap)
    std::swap(Op0, Op1);

  // Since SSE has no unsigned integer comparisons, we need to flip  the sign
  // bits of the inputs before performing those operations.
  if (FlipSigns) {
    MVT EltVT = VT.getVectorElementType();
    SDValue SignBit = DAG.getConstant(APInt::getSignBit(EltVT.getSizeInBits()),
                                      EltVT);
    std::vector<SDValue> SignBits(VT.getVectorNumElements(), SignBit);
    SDValue SignVec = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &SignBits[0],
                                    SignBits.size());
    Op0 = DAG.getNode(ISD::XOR, dl, VT, Op0, SignVec);
    Op1 = DAG.getNode(ISD::XOR, dl, VT, Op1, SignVec);
  }

  SDValue Result = DAG.getNode(Opc, dl, VT, Op0, Op1);

  // If the logical-not of the result is required, perform that now.
  if (Invert)
    Result = DAG.getNOT(dl, Result, VT);

  return Result;
}

// isX86LogicalCmp - Return true if opcode is a X86 logical comparison.
static bool isX86LogicalCmp(SDValue Op) {
  unsigned Opc = Op.getNode()->getOpcode();
  if (Opc == X86ISD::CMP || Opc == X86ISD::COMI || Opc == X86ISD::UCOMI)
    return true;
  if (Op.getResNo() == 1 &&
      (Opc == X86ISD::ADD ||
       Opc == X86ISD::SUB ||
       Opc == X86ISD::SMUL ||
       Opc == X86ISD::UMUL ||
       Opc == X86ISD::INC ||
       Opc == X86ISD::DEC))
    return true;

  return false;
}

SDValue X86TargetLowering::LowerSELECT(SDValue Op, SelectionDAG &DAG) {
  bool addTest = true;
  SDValue Cond  = Op.getOperand(0);
  DebugLoc dl = Op.getDebugLoc();
  SDValue CC;

  if (Cond.getOpcode() == ISD::SETCC)
    Cond = LowerSETCC(Cond, DAG);

  // If condition flag is set by a X86ISD::CMP, then use it as the condition
  // setting operand in place of the X86ISD::SETCC.
  if (Cond.getOpcode() == X86ISD::SETCC) {
    CC = Cond.getOperand(0);

    SDValue Cmp = Cond.getOperand(1);
    unsigned Opc = Cmp.getOpcode();
    MVT VT = Op.getValueType();

    bool IllegalFPCMov = false;
    if (VT.isFloatingPoint() && !VT.isVector() &&
        !isScalarFPTypeInSSEReg(VT))  // FPStack?
      IllegalFPCMov = !hasFPCMov(cast<ConstantSDNode>(CC)->getSExtValue());

    if ((isX86LogicalCmp(Cmp) && !IllegalFPCMov) ||
        Opc == X86ISD::BT) { // FIXME
      Cond = Cmp;
      addTest = false;
    }
  }

  if (addTest) {
    CC = DAG.getConstant(X86::COND_NE, MVT::i8);
    Cond = EmitTest(Cond, X86::COND_NE, DAG);
  }

  SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Flag);
  SmallVector<SDValue, 4> 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, dl, VTs, &Ops[0], Ops.size());
}

// isAndOrOfSingleUseSetCCs - Return true if node is an ISD::AND or
// ISD::OR of two X86ISD::SETCC nodes each of which has no other use apart
// from the AND / OR.
static bool isAndOrOfSetCCs(SDValue Op, unsigned &Opc) {
  Opc = Op.getOpcode();
  if (Opc != ISD::OR && Opc != ISD::AND)
    return false;
  return (Op.getOperand(0).getOpcode() == X86ISD::SETCC &&
          Op.getOperand(0).hasOneUse() &&
          Op.getOperand(1).getOpcode() == X86ISD::SETCC &&
          Op.getOperand(1).hasOneUse());
}

// isXor1OfSetCC - Return true if node is an ISD::XOR of a X86ISD::SETCC and
// 1 and that the SETCC node has a single use.
static bool isXor1OfSetCC(SDValue Op) {
  if (Op.getOpcode() != ISD::XOR)
    return false;
  ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
  if (N1C && N1C->getAPIntValue() == 1) {
    return Op.getOperand(0).getOpcode() == X86ISD::SETCC &&
      Op.getOperand(0).hasOneUse();
  }
  return false;
}

SDValue X86TargetLowering::LowerBRCOND(SDValue Op, SelectionDAG &DAG) {
  bool addTest = true;
  SDValue Chain = Op.getOperand(0);
  SDValue Cond  = Op.getOperand(1);
  SDValue Dest  = Op.getOperand(2);
  DebugLoc dl = Op.getDebugLoc();
  SDValue CC;

  if (Cond.getOpcode() == ISD::SETCC)
    Cond = LowerSETCC(Cond, DAG);
#if 0
  // FIXME: LowerXALUO doesn't handle these!!
  else if (Cond.getOpcode() == X86ISD::ADD  ||
           Cond.getOpcode() == X86ISD::SUB  ||
           Cond.getOpcode() == X86ISD::SMUL ||
           Cond.getOpcode() == X86ISD::UMUL)
    Cond = LowerXALUO(Cond, DAG);
#endif

  // If condition flag is set by a X86ISD::CMP, then use it as the condition
  // setting operand in place of the X86ISD::SETCC.
  if (Cond.getOpcode() == X86ISD::SETCC) {
    CC = Cond.getOperand(0);

    SDValue Cmp = Cond.getOperand(1);
    unsigned Opc = Cmp.getOpcode();
    // FIXME: WHY THE SPECIAL CASING OF LogicalCmp??
    if (isX86LogicalCmp(Cmp) || Opc == X86ISD::BT) {
      Cond = Cmp;
      addTest = false;
    } else {
      switch (cast<ConstantSDNode>(CC)->getZExtValue()) {
      default: break;
      case X86::COND_O:
      case X86::COND_B:
        // These can only come from an arithmetic instruction with overflow,
        // e.g. SADDO, UADDO.
        Cond = Cond.getNode()->getOperand(1);
        addTest = false;
        break;
      }
    }
  } else {
    unsigned CondOpc;
    if (Cond.hasOneUse() && isAndOrOfSetCCs(Cond, CondOpc)) {
      SDValue Cmp = Cond.getOperand(0).getOperand(1);
      if (CondOpc == ISD::OR) {
        // Also, recognize the pattern generated by an FCMP_UNE. We can emit
        // two branches instead of an explicit OR instruction with a
        // separate test.
        if (Cmp == Cond.getOperand(1).getOperand(1) &&
            isX86LogicalCmp(Cmp)) {
          CC = Cond.getOperand(0).getOperand(0);
          Chain = DAG.getNode(X86ISD::BRCOND, dl, Op.getValueType(),
                              Chain, Dest, CC, Cmp);
          CC = Cond.getOperand(1).getOperand(0);
          Cond = Cmp;
          addTest = false;
        }
      } else { // ISD::AND
        // Also, recognize the pattern generated by an FCMP_OEQ. We can emit
        // two branches instead of an explicit AND instruction with a
        // separate test. However, we only do this if this block doesn't
        // have a fall-through edge, because this requires an explicit
        // jmp when the condition is false.
        if (Cmp == Cond.getOperand(1).getOperand(1) &&
            isX86LogicalCmp(Cmp) &&
            Op.getNode()->hasOneUse()) {
          X86::CondCode CCode =
            (X86::CondCode)Cond.getOperand(0).getConstantOperandVal(0);
          CCode = X86::GetOppositeBranchCondition(CCode);
          CC = DAG.getConstant(CCode, MVT::i8);
          SDValue User = SDValue(*Op.getNode()->use_begin(), 0);
          // Look for an unconditional branch following this conditional branch.
          // We need this because we need to reverse the successors in order
          // to implement FCMP_OEQ.
          if (User.getOpcode() == ISD::BR) {
            SDValue FalseBB = User.getOperand(1);
            SDValue NewBR =
              DAG.UpdateNodeOperands(User, User.getOperand(0), Dest);
            assert(NewBR == User);
            Dest = FalseBB;

            Chain = DAG.getNode(X86ISD::BRCOND, dl, Op.getValueType(),
                                Chain, Dest, CC, Cmp);
            X86::CondCode CCode =
              (X86::CondCode)Cond.getOperand(1).getConstantOperandVal(0);
            CCode = X86::GetOppositeBranchCondition(CCode);
            CC = DAG.getConstant(CCode, MVT::i8);
            Cond = Cmp;
            addTest = false;
          }
        }
      }
    } else if (Cond.hasOneUse() && isXor1OfSetCC(Cond)) {
      // Recognize for xorb (setcc), 1 patterns. The xor inverts the condition.
      // It should be transformed during dag combiner except when the condition
      // is set by a arithmetics with overflow node.
      X86::CondCode CCode =
        (X86::CondCode)Cond.getOperand(0).getConstantOperandVal(0);
      CCode = X86::GetOppositeBranchCondition(CCode);
      CC = DAG.getConstant(CCode, MVT::i8);
      Cond = Cond.getOperand(0).getOperand(1);
      addTest = false;
    }
  }

  if (addTest) {
    CC = DAG.getConstant(X86::COND_NE, MVT::i8);
    Cond = EmitTest(Cond, X86::COND_NE, DAG);
  }
  return DAG.getNode(X86ISD::BRCOND, dl, Op.getValueType(),
                     Chain, Dest, CC, Cond);
}


// Lower dynamic stack allocation to _alloca call for Cygwin/Mingw targets.
// Calls to _alloca is needed to probe the stack when allocating more than 4k
// bytes in one go. Touching the stack at 4K increments is necessary to ensure
// that the guard pages used by the OS virtual memory manager are allocated in
// correct sequence.
SDValue
X86TargetLowering::LowerDYNAMIC_STACKALLOC(SDValue Op,
                                           SelectionDAG &DAG) {
  assert(Subtarget->isTargetCygMing() &&
         "This should be used only on Cygwin/Mingw targets");
  DebugLoc dl = Op.getDebugLoc();

  // Get the inputs.
  SDValue Chain = Op.getOperand(0);
  SDValue Size  = Op.getOperand(1);
  // FIXME: Ensure alignment here

  SDValue Flag;

  MVT IntPtr = getPointerTy();
  MVT SPTy = Subtarget->is64Bit() ? MVT::i64 : MVT::i32;

  Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(0, true));

  Chain = DAG.getCopyToReg(Chain, dl, X86::EAX, Size, Flag);
  Flag = Chain.getValue(1);

  SDVTList  NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
  SDValue Ops[] = { Chain,
                      DAG.getTargetExternalSymbol("_alloca", IntPtr),
                      DAG.getRegister(X86::EAX, IntPtr),
                      DAG.getRegister(X86StackPtr, SPTy),
                      Flag };
  Chain = DAG.getNode(X86ISD::CALL, dl, NodeTys, Ops, 5);
  Flag = Chain.getValue(1);

  Chain = DAG.getCALLSEQ_END(Chain,
                             DAG.getIntPtrConstant(0, true),
                             DAG.getIntPtrConstant(0, true),
                             Flag);

  Chain = DAG.getCopyFromReg(Chain, dl, X86StackPtr, SPTy).getValue(1);

  SDValue Ops1[2] = { Chain.getValue(0), Chain };
  return DAG.getMergeValues(Ops1, 2, dl);
}

SDValue
X86TargetLowering::EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
                                           SDValue Chain,
                                           SDValue Dst, SDValue Src,
                                           SDValue Size, unsigned Align,
                                           const Value *DstSV,
                                           uint64_t DstSVOff) {
  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);

  // If not DWORD aligned or size is more than the threshold, call the library.
  // The libc version is likely to be faster for these cases. It can use the
  // address value and run time information about the CPU.
  if ((Align & 3) != 0 ||
      !ConstantSize ||
      ConstantSize->getZExtValue() >
        getSubtarget()->getMaxInlineSizeThreshold()) {
    SDValue InFlag(0, 0);

    // Check to see if there is a specialized entry-point for memory zeroing.
    ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);

    if (const char *bzeroEntry =  V &&
        V->isNullValue() ? Subtarget->getBZeroEntry() : 0) {
      MVT IntPtr = getPointerTy();
      const Type *IntPtrTy = TD->getIntPtrType();
      TargetLowering::ArgListTy Args;
      TargetLowering::ArgListEntry Entry;
      Entry.Node = Dst;
      Entry.Ty = IntPtrTy;
      Args.push_back(Entry);
      Entry.Node = Size;
      Args.push_back(Entry);
      std::pair<SDValue,SDValue> CallResult =
        LowerCallTo(Chain, Type::VoidTy, false, false, false, false,
                    0, CallingConv::C, false,
                    DAG.getExternalSymbol(bzeroEntry, IntPtr), Args, DAG, dl);
      return CallResult.second;
    }

    // Otherwise have the target-independent code call memset.
    return SDValue();
  }

  uint64_t SizeVal = ConstantSize->getZExtValue();
  SDValue InFlag(0, 0);
  MVT AVT;
  SDValue Count;
  ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Src);
  unsigned BytesLeft = 0;
  bool TwoRepStos = false;
  if (ValC) {
    unsigned ValReg;
    uint64_t Val = ValC->getZExtValue() & 255;

    // If the value is a constant, then we can potentially use larger sets.
    switch (Align & 3) {
    case 2:   // WORD aligned
      AVT = MVT::i16;
      ValReg = X86::AX;
      Val = (Val << 8) | Val;
      break;
    case 0:  // DWORD aligned
      AVT = MVT::i32;
      ValReg = X86::EAX;
      Val = (Val << 8)  | Val;
      Val = (Val << 16) | Val;
      if (Subtarget->is64Bit() && ((Align & 0x7) == 0)) {  // QWORD aligned
        AVT = MVT::i64;
        ValReg = X86::RAX;
        Val = (Val << 32) | Val;
      }
      break;
    default:  // Byte aligned
      AVT = MVT::i8;
      ValReg = X86::AL;
      Count = DAG.getIntPtrConstant(SizeVal);
      break;
    }

    if (AVT.bitsGT(MVT::i8)) {
      unsigned UBytes = AVT.getSizeInBits() / 8;
      Count = DAG.getIntPtrConstant(SizeVal / UBytes);
      BytesLeft = SizeVal % UBytes;
    }

    Chain  = DAG.getCopyToReg(Chain, dl, ValReg, DAG.getConstant(Val, AVT),
                              InFlag);
    InFlag = Chain.getValue(1);
  } else {
    AVT = MVT::i8;
    Count  = DAG.getIntPtrConstant(SizeVal);
    Chain  = DAG.getCopyToReg(Chain, dl, X86::AL, Src, InFlag);
    InFlag = Chain.getValue(1);
  }

  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RCX :
                                                              X86::ECX,
                            Count, InFlag);
  InFlag = Chain.getValue(1);
  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RDI :
                                                              X86::EDI,
                            Dst, InFlag);
  InFlag = Chain.getValue(1);

  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
  SmallVector<SDValue, 8> Ops;
  Ops.push_back(Chain);
  Ops.push_back(DAG.getValueType(AVT));
  Ops.push_back(InFlag);
  Chain  = DAG.getNode(X86ISD::REP_STOS, dl, Tys, &Ops[0], Ops.size());

  if (TwoRepStos) {
    InFlag = Chain.getValue(1);
    Count  = Size;
    MVT CVT = Count.getValueType();
    SDValue Left = DAG.getNode(ISD::AND, dl, CVT, Count,
                               DAG.getConstant((AVT == MVT::i64) ? 7 : 3, CVT));
    Chain  = DAG.getCopyToReg(Chain, dl, (CVT == MVT::i64) ? X86::RCX :
                                                             X86::ECX,
                              Left, InFlag);
    InFlag = Chain.getValue(1);
    Tys = DAG.getVTList(MVT::Other, MVT::Flag);
    Ops.clear();
    Ops.push_back(Chain);
    Ops.push_back(DAG.getValueType(MVT::i8));
    Ops.push_back(InFlag);
    Chain  = DAG.getNode(X86ISD::REP_STOS, dl, Tys, &Ops[0], Ops.size());
  } else if (BytesLeft) {
    // Handle the last 1 - 7 bytes.
    unsigned Offset = SizeVal - BytesLeft;
    MVT AddrVT = Dst.getValueType();
    MVT SizeVT = Size.getValueType();

    Chain = DAG.getMemset(Chain, dl,
                          DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
                                      DAG.getConstant(Offset, AddrVT)),
                          Src,
                          DAG.getConstant(BytesLeft, SizeVT),
                          Align, DstSV, DstSVOff + Offset);
  }

  // TODO: Use a Tokenfactor, as in memcpy, instead of a single chain.
  return Chain;
}

SDValue
X86TargetLowering::EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl,
                                      SDValue Chain, SDValue Dst, SDValue Src,
                                      SDValue Size, unsigned Align,
                                      bool AlwaysInline,
                                      const Value *DstSV, uint64_t DstSVOff,
                                      const Value *SrcSV, uint64_t SrcSVOff) {
  // This requires the copy size to be a constant, preferrably
  // within a subtarget-specific limit.
  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
  if (!ConstantSize)
    return SDValue();
  uint64_t SizeVal = ConstantSize->getZExtValue();
  if (!AlwaysInline && SizeVal > getSubtarget()->getMaxInlineSizeThreshold())
    return SDValue();

  /// If not DWORD aligned, call the library.
  if ((Align & 3) != 0)
    return SDValue();

  // DWORD aligned
  MVT AVT = MVT::i32;
  if (Subtarget->is64Bit() && ((Align & 0x7) == 0))  // QWORD aligned
    AVT = MVT::i64;

  unsigned UBytes = AVT.getSizeInBits() / 8;
  unsigned CountVal = SizeVal / UBytes;
  SDValue Count = DAG.getIntPtrConstant(CountVal);
  unsigned BytesLeft = SizeVal % UBytes;

  SDValue InFlag(0, 0);
  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RCX :
                                                              X86::ECX,
                            Count, InFlag);
  InFlag = Chain.getValue(1);
  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RDI :
                                                             X86::EDI,
                            Dst, InFlag);
  InFlag = Chain.getValue(1);
  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RSI :
                                                              X86::ESI,
                            Src, InFlag);
  InFlag = Chain.getValue(1);

  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
  SmallVector<SDValue, 8> Ops;
  Ops.push_back(Chain);
  Ops.push_back(DAG.getValueType(AVT));
  Ops.push_back(InFlag);
  SDValue RepMovs = DAG.getNode(X86ISD::REP_MOVS, dl, Tys, &Ops[0], Ops.size());

  SmallVector<SDValue, 4> Results;
  Results.push_back(RepMovs);
  if (BytesLeft) {
    // Handle the last 1 - 7 bytes.
    unsigned Offset = SizeVal - BytesLeft;
    MVT DstVT = Dst.getValueType();
    MVT SrcVT = Src.getValueType();
    MVT SizeVT = Size.getValueType();
    Results.push_back(DAG.getMemcpy(Chain, dl,
                                    DAG.getNode(ISD::ADD, dl, DstVT, Dst,
                                                DAG.getConstant(Offset, DstVT)),
                                    DAG.getNode(ISD::ADD, dl, SrcVT, Src,
                                                DAG.getConstant(Offset, SrcVT)),
                                    DAG.getConstant(BytesLeft, SizeVT),
                                    Align, AlwaysInline,
                                    DstSV, DstSVOff + Offset,
                                    SrcSV, SrcSVOff + Offset));
  }

  return DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                     &Results[0], Results.size());
}

SDValue X86TargetLowering::LowerVASTART(SDValue Op, SelectionDAG &DAG) {
  const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
  DebugLoc dl = Op.getDebugLoc();

  if (!Subtarget->is64Bit()) {
    // vastart just stores the address of the VarArgsFrameIndex slot into the
    // memory location argument.
    SDValue FR = DAG.getFrameIndex(VarArgsFrameIndex, getPointerTy());
    return DAG.getStore(Op.getOperand(0), dl, FR, Op.getOperand(1), SV, 0);
  }

  // __va_list_tag:
  //   gp_offset         (0 - 6 * 8)
  //   fp_offset         (48 - 48 + 8 * 16)
  //   overflow_arg_area (point to parameters coming in memory).
  //   reg_save_area
  SmallVector<SDValue, 8> MemOps;
  SDValue FIN = Op.getOperand(1);
  // Store gp_offset
  SDValue Store = DAG.getStore(Op.getOperand(0), dl,
                                 DAG.getConstant(VarArgsGPOffset, MVT::i32),
                                 FIN, SV, 0);
  MemOps.push_back(Store);

  // Store fp_offset
  FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(),
                    FIN, DAG.getIntPtrConstant(4));
  Store = DAG.getStore(Op.getOperand(0), dl,
                       DAG.getConstant(VarArgsFPOffset, MVT::i32),
                       FIN, SV, 0);
  MemOps.push_back(Store);

  // Store ptr to overflow_arg_area
  FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(),
                    FIN, DAG.getIntPtrConstant(4));
  SDValue OVFIN = DAG.getFrameIndex(VarArgsFrameIndex, getPointerTy());
  Store = DAG.getStore(Op.getOperand(0), dl, OVFIN, FIN, SV, 0);
  MemOps.push_back(Store);

  // Store ptr to reg_save_area.
  FIN = DAG.getNode(ISD::ADD, dl, getPointerTy(),
                    FIN, DAG.getIntPtrConstant(8));
  SDValue RSFIN = DAG.getFrameIndex(RegSaveFrameIndex, getPointerTy());
  Store = DAG.getStore(Op.getOperand(0), dl, RSFIN, FIN, SV, 0);
  MemOps.push_back(Store);
  return DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                     &MemOps[0], MemOps.size());
}

SDValue X86TargetLowering::LowerVAARG(SDValue Op, SelectionDAG &DAG) {
  // X86-64 va_list is a struct { i32, i32, i8*, i8* }.
  assert(Subtarget->is64Bit() && "This code only handles 64-bit va_arg!");
  SDValue Chain = Op.getOperand(0);
  SDValue SrcPtr = Op.getOperand(1);
  SDValue SrcSV = Op.getOperand(2);

  llvm_report_error("VAArgInst is not yet implemented for x86-64!");
  return SDValue();
}

SDValue X86TargetLowering::LowerVACOPY(SDValue Op, SelectionDAG &DAG) {
  // X86-64 va_list is a struct { i32, i32, i8*, i8* }.
  assert(Subtarget->is64Bit() && "This code only handles 64-bit va_copy!");
  SDValue Chain = Op.getOperand(0);
  SDValue DstPtr = Op.getOperand(1);
  SDValue SrcPtr = Op.getOperand(2);
  const Value *DstSV = cast<SrcValueSDNode>(Op.getOperand(3))->getValue();
  const Value *SrcSV = cast<SrcValueSDNode>(Op.getOperand(4))->getValue();
  DebugLoc dl = Op.getDebugLoc();

  return DAG.getMemcpy(Chain, dl, DstPtr, SrcPtr,
                       DAG.getIntPtrConstant(24), 8, false,
                       DstSV, 0, SrcSV, 0);
}

SDValue
X86TargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) {
  DebugLoc dl = Op.getDebugLoc();
  unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
  switch (IntNo) {
  default: return SDValue();    // Don't custom lower most intrinsics.
  // Comparison intrinsics.
  case Intrinsic::x86_sse_comieq_ss:
  case Intrinsic::x86_sse_comilt_ss:
  case Intrinsic::x86_sse_comile_ss:
  case Intrinsic::x86_sse_comigt_ss:
  case Intrinsic::x86_sse_comige_ss:
  case Intrinsic::x86_sse_comineq_ss:
  case Intrinsic::x86_sse_ucomieq_ss:
  case Intrinsic::x86_sse_ucomilt_ss:
  case Intrinsic::x86_sse_ucomile_ss:
  case Intrinsic::x86_sse_ucomigt_ss:
  case Intrinsic::x86_sse_ucomige_ss:
  case Intrinsic::x86_sse_ucomineq_ss:
  case Intrinsic::x86_sse2_comieq_sd:
  case Intrinsic::x86_sse2_comilt_sd:
  case Intrinsic::x86_sse2_comile_sd:
  case Intrinsic::x86_sse2_comigt_sd:
  case Intrinsic::x86_sse2_comige_sd:
  case Intrinsic::x86_sse2_comineq_sd:
  case Intrinsic::x86_sse2_ucomieq_sd:
  case Intrinsic::x86_sse2_ucomilt_sd:
  case Intrinsic::x86_sse2_ucomile_sd:
  case Intrinsic::x86_sse2_ucomigt_sd:
  case Intrinsic::x86_sse2_ucomige_sd:
  case Intrinsic::x86_sse2_ucomineq_sd: {
    unsigned Opc = 0;
    ISD::CondCode CC = ISD::SETCC_INVALID;
    switch (IntNo) {
    default: break;
    case Intrinsic::x86_sse_comieq_ss:
    case Intrinsic::x86_sse2_comieq_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETEQ;
      break;
    case Intrinsic::x86_sse_comilt_ss:
    case Intrinsic::x86_sse2_comilt_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETLT;
      break;
    case Intrinsic::x86_sse_comile_ss:
    case Intrinsic::x86_sse2_comile_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETLE;
      break;
    case Intrinsic::x86_sse_comigt_ss:
    case Intrinsic::x86_sse2_comigt_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETGT;
      break;
    case Intrinsic::x86_sse_comige_ss:
    case Intrinsic::x86_sse2_comige_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETGE;
      break;
    case Intrinsic::x86_sse_comineq_ss:
    case Intrinsic::x86_sse2_comineq_sd:
      Opc = X86ISD::COMI;
      CC = ISD::SETNE;
      break;
    case Intrinsic::x86_sse_ucomieq_ss:
    case Intrinsic::x86_sse2_ucomieq_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETEQ;
      break;
    case Intrinsic::x86_sse_ucomilt_ss:
    case Intrinsic::x86_sse2_ucomilt_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETLT;
      break;
    case Intrinsic::x86_sse_ucomile_ss:
    case Intrinsic::x86_sse2_ucomile_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETLE;
      break;
    case Intrinsic::x86_sse_ucomigt_ss:
    case Intrinsic::x86_sse2_ucomigt_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETGT;
      break;
    case Intrinsic::x86_sse_ucomige_ss:
    case Intrinsic::x86_sse2_ucomige_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETGE;
      break;
    case Intrinsic::x86_sse_ucomineq_ss:
    case Intrinsic::x86_sse2_ucomineq_sd:
      Opc = X86ISD::UCOMI;
      CC = ISD::SETNE;
      break;
    }

    SDValue LHS = Op.getOperand(1);
    SDValue RHS = Op.getOperand(2);
    unsigned X86CC = TranslateX86CC(CC, true, LHS, RHS, DAG);
    SDValue Cond = DAG.getNode(Opc, dl, MVT::i32, LHS, RHS);
    SDValue SetCC = DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
                                DAG.getConstant(X86CC, MVT::i8), Cond);
    return DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, SetCC);
  }
  // ptest intrinsics. The intrinsic these come from are designed to return
  // an integer value, not just an instruction so lower it to the ptest
  // pattern and a setcc for the result.
  case Intrinsic::x86_sse41_ptestz:
  case Intrinsic::x86_sse41_ptestc:
  case Intrinsic::x86_sse41_ptestnzc:{
    unsigned X86CC = 0;
    switch (IntNo) {
    default: llvm_unreachable("Bad fallthrough in Intrinsic lowering.");
    case Intrinsic::x86_sse41_ptestz:
      // ZF = 1
      X86CC = X86::COND_E;
      break;
    case Intrinsic::x86_sse41_ptestc:
      // CF = 1
      X86CC = X86::COND_B;
      break;
    case Intrinsic::x86_sse41_ptestnzc: 
      // ZF and CF = 0
      X86CC = X86::COND_A;
      break;
    }
       
    SDValue LHS = Op.getOperand(1);
    SDValue RHS = Op.getOperand(2);
    SDValue Test = DAG.getNode(X86ISD::PTEST, dl, MVT::i32, LHS, RHS);
    SDValue CC = DAG.getConstant(X86CC, MVT::i8);
    SDValue SetCC = DAG.getNode(X86ISD::SETCC, dl, MVT::i8, CC, Test);
    return DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, SetCC);
  }

  // Fix vector shift instructions where the last operand is a non-immediate
  // i32 value.
  case Intrinsic::x86_sse2_pslli_w:
  case Intrinsic::x86_sse2_pslli_d:
  case Intrinsic::x86_sse2_pslli_q:
  case Intrinsic::x86_sse2_psrli_w:
  case Intrinsic::x86_sse2_psrli_d:
  case Intrinsic::x86_sse2_psrli_q:
  case Intrinsic::x86_sse2_psrai_w:
  case Intrinsic::x86_sse2_psrai_d:
  case Intrinsic::x86_mmx_pslli_w:
  case Intrinsic::x86_mmx_pslli_d:
  case Intrinsic::x86_mmx_pslli_q:
  case Intrinsic::x86_mmx_psrli_w:
  case Intrinsic::x86_mmx_psrli_d:
  case Intrinsic::x86_mmx_psrli_q:
  case Intrinsic::x86_mmx_psrai_w:
  case Intrinsic::x86_mmx_psrai_d: {
    SDValue ShAmt = Op.getOperand(2);
    if (isa<ConstantSDNode>(ShAmt))
      return SDValue();

    unsigned NewIntNo = 0;
    MVT ShAmtVT = MVT::v4i32;
    switch (IntNo) {
    case Intrinsic::x86_sse2_pslli_w:
      NewIntNo = Intrinsic::x86_sse2_psll_w;
      break;
    case Intrinsic::x86_sse2_pslli_d:
      NewIntNo = Intrinsic::x86_sse2_psll_d;
      break;
    case Intrinsic::x86_sse2_pslli_q:
      NewIntNo = Intrinsic::x86_sse2_psll_q;
      break;
    case Intrinsic::x86_sse2_psrli_w:
      NewIntNo = Intrinsic::x86_sse2_psrl_w;
      break;
    case Intrinsic::x86_sse2_psrli_d:
      NewIntNo = Intrinsic::x86_sse2_psrl_d;
      break;
    case Intrinsic::x86_sse2_psrli_q:
      NewIntNo = Intrinsic::x86_sse2_psrl_q;
      break;
    case Intrinsic::x86_sse2_psrai_w:
      NewIntNo = Intrinsic::x86_sse2_psra_w;
      break;
    case Intrinsic::x86_sse2_psrai_d:
      NewIntNo = Intrinsic::x86_sse2_psra_d;
      break;
    default: {
      ShAmtVT = MVT::v2i32;
      switch (IntNo) {
      case Intrinsic::x86_mmx_pslli_w:
        NewIntNo = Intrinsic::x86_mmx_psll_w;
        break;
      case Intrinsic::x86_mmx_pslli_d:
        NewIntNo = Intrinsic::x86_mmx_psll_d;
        break;
      case Intrinsic::x86_mmx_pslli_q:
        NewIntNo = Intrinsic::x86_mmx_psll_q;
        break;
      case Intrinsic::x86_mmx_psrli_w:
        NewIntNo = Intrinsic::x86_mmx_psrl_w;
        break;
      case Intrinsic::x86_mmx_psrli_d:
        NewIntNo = Intrinsic::x86_mmx_psrl_d;
        break;
      case Intrinsic::x86_mmx_psrli_q:
        NewIntNo = Intrinsic::x86_mmx_psrl_q;
        break;
      case Intrinsic::x86_mmx_psrai_w:
        NewIntNo = Intrinsic::x86_mmx_psra_w;
        break;
      case Intrinsic::x86_mmx_psrai_d:
        NewIntNo = Intrinsic::x86_mmx_psra_d;
        break;
      default: llvm_unreachable("Impossible intrinsic");  // Can't reach here.
      }
      break;
    }
    }
    MVT VT = Op.getValueType();
    ShAmt = DAG.getNode(ISD::BIT_CONVERT, dl, VT,
                        DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, ShAmtVT, ShAmt));
    return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(NewIntNo, MVT::i32),
                       Op.getOperand(1), ShAmt);
  }
  }
}

SDValue X86TargetLowering::LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) {
  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
  DebugLoc dl = Op.getDebugLoc();

  if (Depth > 0) {
    SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
    SDValue Offset =
      DAG.getConstant(TD->getPointerSize(),
                      Subtarget->is64Bit() ? MVT::i64 : MVT::i32);
    return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
                       DAG.getNode(ISD::ADD, dl, getPointerTy(),
                                   FrameAddr, Offset),
                       NULL, 0);
  }

  // Just load the return address.
  SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
  return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
                     RetAddrFI, NULL, 0);
}

SDValue X86TargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) {
  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
  MFI->setFrameAddressIsTaken(true);
  MVT VT = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();  // FIXME probably not meaningful
  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
  unsigned FrameReg = Subtarget->is64Bit() ? X86::RBP : X86::EBP;
  SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl, FrameReg, VT);
  while (Depth--)
    FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr, NULL, 0);
  return FrameAddr;
}

SDValue X86TargetLowering::LowerFRAME_TO_ARGS_OFFSET(SDValue Op,
                                                     SelectionDAG &DAG) {
  return DAG.getIntPtrConstant(2*TD->getPointerSize());
}

SDValue X86TargetLowering::LowerEH_RETURN(SDValue Op, SelectionDAG &DAG)
{
  MachineFunction &MF = DAG.getMachineFunction();
  SDValue Chain     = Op.getOperand(0);
  SDValue Offset    = Op.getOperand(1);
  SDValue Handler   = Op.getOperand(2);
  DebugLoc dl       = Op.getDebugLoc();

  SDValue Frame = DAG.getRegister(Subtarget->is64Bit() ? X86::RBP : X86::EBP,
                                  getPointerTy());
  unsigned StoreAddrReg = (Subtarget->is64Bit() ? X86::RCX : X86::ECX);

  SDValue StoreAddr = DAG.getNode(ISD::SUB, dl, getPointerTy(), Frame,
                                  DAG.getIntPtrConstant(-TD->getPointerSize()));
  StoreAddr = DAG.getNode(ISD::ADD, dl, getPointerTy(), StoreAddr, Offset);
  Chain = DAG.getStore(Chain, dl, Handler, StoreAddr, NULL, 0);
  Chain = DAG.getCopyToReg(Chain, dl, StoreAddrReg, StoreAddr);
  MF.getRegInfo().addLiveOut(StoreAddrReg);

  return DAG.getNode(X86ISD::EH_RETURN, dl,
                     MVT::Other,
                     Chain, DAG.getRegister(StoreAddrReg, getPointerTy()));
}

SDValue X86TargetLowering::LowerTRAMPOLINE(SDValue Op,
                                             SelectionDAG &DAG) {
  SDValue Root = Op.getOperand(0);
  SDValue Trmp = Op.getOperand(1); // trampoline
  SDValue FPtr = Op.getOperand(2); // nested function
  SDValue Nest = Op.getOperand(3); // 'nest' parameter value
  DebugLoc dl  = Op.getDebugLoc();

  const Value *TrmpAddr = cast<SrcValueSDNode>(Op.getOperand(4))->getValue();

  const X86InstrInfo *TII =
    ((X86TargetMachine&)getTargetMachine()).getInstrInfo();

  if (Subtarget->is64Bit()) {
    SDValue OutChains[6];

    // Large code-model.

    const unsigned char JMP64r  = TII->getBaseOpcodeFor(X86::JMP64r);
    const unsigned char MOV64ri = TII->getBaseOpcodeFor(X86::MOV64ri);

    const unsigned char N86R10 = RegInfo->getX86RegNum(X86::R10);
    const unsigned char N86R11 = RegInfo->getX86RegNum(X86::R11);

    const unsigned char REX_WB = 0x40 | 0x08 | 0x01; // REX prefix

    // Load the pointer to the nested function into R11.
    unsigned OpCode = ((MOV64ri | N86R11) << 8) | REX_WB; // movabsq r11
    SDValue Addr = Trmp;
    OutChains[0] = DAG.getStore(Root, dl, DAG.getConstant(OpCode, MVT::i16),
                                Addr, TrmpAddr, 0);

    Addr = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
                       DAG.getConstant(2, MVT::i64));
    OutChains[1] = DAG.getStore(Root, dl, FPtr, Addr, TrmpAddr, 2, false, 2);

    // Load the 'nest' parameter value into R10.
    // R10 is specified in X86CallingConv.td
    OpCode = ((MOV64ri | N86R10) << 8) | REX_WB; // movabsq r10
    Addr = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
                       DAG.getConstant(10, MVT::i64));
    OutChains[2] = DAG.getStore(Root, dl, DAG.getConstant(OpCode, MVT::i16),
                                Addr, TrmpAddr, 10);

    Addr = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
                       DAG.getConstant(12, MVT::i64));
    OutChains[3] = DAG.getStore(Root, dl, Nest, Addr, TrmpAddr, 12, false, 2);

    // Jump to the nested function.
    OpCode = (JMP64r << 8) | REX_WB; // jmpq *...
    Addr = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
                       DAG.getConstant(20, MVT::i64));
    OutChains[4] = DAG.getStore(Root, dl, DAG.getConstant(OpCode, MVT::i16),
                                Addr, TrmpAddr, 20);

    unsigned char ModRM = N86R11 | (4 << 3) | (3 << 6); // ...r11
    Addr = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
                       DAG.getConstant(22, MVT::i64));
    OutChains[5] = DAG.getStore(Root, dl, DAG.getConstant(ModRM, MVT::i8), Addr,
                                TrmpAddr, 22);

    SDValue Ops[] =
      { Trmp, DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 6) };
    return DAG.getMergeValues(Ops, 2, dl);
  } else {
    const Function *Func =
      cast<Function>(cast<SrcValueSDNode>(Op.getOperand(5))->getValue());
    unsigned CC = Func->getCallingConv();
    unsigned NestReg;

    switch (CC) {
    default:
      llvm_unreachable("Unsupported calling convention");
    case CallingConv::C:
    case CallingConv::X86_StdCall: {
      // Pass 'nest' parameter in ECX.
      // Must be kept in sync with X86CallingConv.td
      NestReg = X86::ECX;

      // Check that ECX wasn't needed by an 'inreg' parameter.
      const FunctionType *FTy = Func->getFunctionType();
      const AttrListPtr &Attrs = Func->getAttributes();

      if (!Attrs.isEmpty() && !Func->isVarArg()) {
        unsigned InRegCount = 0;
        unsigned Idx = 1;

        for (FunctionType::param_iterator I = FTy->param_begin(),
             E = FTy->param_end(); I != E; ++I, ++Idx)
          if (Attrs.paramHasAttr(Idx, Attribute::InReg))
            // FIXME: should only count parameters that are lowered to integers.
            InRegCount += (TD->getTypeSizeInBits(*I) + 31) / 32;

        if (InRegCount > 2) {
          llvm_report_error("Nest register in use - reduce number of inreg parameters!");
        }
      }
      break;
    }
    case CallingConv::X86_FastCall:
    case CallingConv::Fast:
      // Pass 'nest' parameter in EAX.
      // Must be kept in sync with X86CallingConv.td
      NestReg = X86::EAX;
      break;
    }

    SDValue OutChains[4];
    SDValue Addr, Disp;

    Addr = DAG.getNode(ISD::ADD, dl, MVT::i32, Trmp,
                       DAG.getConstant(10, MVT::i32));
    Disp = DAG.getNode(ISD::SUB, dl, MVT::i32, FPtr, Addr);

    const unsigned char MOV32ri = TII->getBaseOpcodeFor(X86::MOV32ri);
    const unsigned char N86Reg = RegInfo->getX86RegNum(NestReg);
    OutChains[0] = DAG.getStore(Root, dl,
                                DAG.getConstant(MOV32ri|N86Reg, MVT::i8),
                                Trmp, TrmpAddr, 0);

    Addr = DAG.getNode(ISD::ADD, dl, MVT::i32, Trmp,
                       DAG.getConstant(1, MVT::i32));
    OutChains[1] = DAG.getStore(Root, dl, Nest, Addr, TrmpAddr, 1, false, 1);

    const unsigned char JMP = TII->getBaseOpcodeFor(X86::JMP);
    Addr = DAG.getNode(ISD::ADD, dl, MVT::i32, Trmp,
                       DAG.getConstant(5, MVT::i32));
    OutChains[2] = DAG.getStore(Root, dl, DAG.getConstant(JMP, MVT::i8), Addr,
                                TrmpAddr, 5, false, 1);

    Addr = DAG.getNode(ISD::ADD, dl, MVT::i32, Trmp,
                       DAG.getConstant(6, MVT::i32));
    OutChains[3] = DAG.getStore(Root, dl, Disp, Addr, TrmpAddr, 6, false, 1);

    SDValue Ops[] =
      { Trmp, DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 4) };
    return DAG.getMergeValues(Ops, 2, dl);
  }
}

SDValue X86TargetLowering::LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) {
  /*
   The rounding mode is in bits 11:10 of FPSR, and has the following
   settings:
     00 Round to nearest
     01 Round to -inf
     10 Round to +inf
     11 Round to 0

  FLT_ROUNDS, on the other hand, expects the following:
    -1 Undefined
     0 Round to 0
     1 Round to nearest
     2 Round to +inf
     3 Round to -inf

  To perform the conversion, we do:
    (((((FPSR & 0x800) >> 11) | ((FPSR & 0x400) >> 9)) + 1) & 3)
  */

  MachineFunction &MF = DAG.getMachineFunction();
  const TargetMachine &TM = MF.getTarget();
  const TargetFrameInfo &TFI = *TM.getFrameInfo();
  unsigned StackAlignment = TFI.getStackAlignment();
  MVT VT = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();

  // Save FP Control Word to stack slot
  int SSFI = MF.getFrameInfo()->CreateStackObject(2, StackAlignment);
  SDValue StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());

  SDValue Chain = DAG.getNode(X86ISD::FNSTCW16m, dl, MVT::Other,
                              DAG.getEntryNode(), StackSlot);

  // Load FP Control Word from stack slot
  SDValue CWD = DAG.getLoad(MVT::i16, dl, Chain, StackSlot, NULL, 0);

  // Transform as necessary
  SDValue CWD1 =
    DAG.getNode(ISD::SRL, dl, MVT::i16,
                DAG.getNode(ISD::AND, dl, MVT::i16,
                            CWD, DAG.getConstant(0x800, MVT::i16)),
                DAG.getConstant(11, MVT::i8));
  SDValue CWD2 =
    DAG.getNode(ISD::SRL, dl, MVT::i16,
                DAG.getNode(ISD::AND, dl, MVT::i16,
                            CWD, DAG.getConstant(0x400, MVT::i16)),
                DAG.getConstant(9, MVT::i8));

  SDValue RetVal =
    DAG.getNode(ISD::AND, dl, MVT::i16,
                DAG.getNode(ISD::ADD, dl, MVT::i16,
                            DAG.getNode(ISD::OR, dl, MVT::i16, CWD1, CWD2),
                            DAG.getConstant(1, MVT::i16)),
                DAG.getConstant(3, MVT::i16));


  return DAG.getNode((VT.getSizeInBits() < 16 ?
                      ISD::TRUNCATE : ISD::ZERO_EXTEND), dl, VT, RetVal);
}

SDValue X86TargetLowering::LowerCTLZ(SDValue Op, SelectionDAG &DAG) {
  MVT VT = Op.getValueType();
  MVT OpVT = VT;
  unsigned NumBits = VT.getSizeInBits();
  DebugLoc dl = Op.getDebugLoc();

  Op = Op.getOperand(0);
  if (VT == MVT::i8) {
    // Zero extend to i32 since there is not an i8 bsr.
    OpVT = MVT::i32;
    Op = DAG.getNode(ISD::ZERO_EXTEND, dl, OpVT, Op);
  }

  // Issue a bsr (scan bits in reverse) which also sets EFLAGS.
  SDVTList VTs = DAG.getVTList(OpVT, MVT::i32);
  Op = DAG.getNode(X86ISD::BSR, dl, VTs, Op);

  // If src is zero (i.e. bsr sets ZF), returns NumBits.
  SmallVector<SDValue, 4> Ops;
  Ops.push_back(Op);
  Ops.push_back(DAG.getConstant(NumBits+NumBits-1, OpVT));
  Ops.push_back(DAG.getConstant(X86::COND_E, MVT::i8));
  Ops.push_back(Op.getValue(1));
  Op = DAG.getNode(X86ISD::CMOV, dl, OpVT, &Ops[0], 4);

  // Finally xor with NumBits-1.
  Op = DAG.getNode(ISD::XOR, dl, OpVT, Op, DAG.getConstant(NumBits-1, OpVT));

  if (VT == MVT::i8)
    Op = DAG.getNode(ISD::TRUNCATE, dl, MVT::i8, Op);
  return Op;
}

SDValue X86TargetLowering::LowerCTTZ(SDValue Op, SelectionDAG &DAG) {
  MVT VT = Op.getValueType();
  MVT OpVT = VT;
  unsigned NumBits = VT.getSizeInBits();
  DebugLoc dl = Op.getDebugLoc();

  Op = Op.getOperand(0);
  if (VT == MVT::i8) {
    OpVT = MVT::i32;
    Op = DAG.getNode(ISD::ZERO_EXTEND, dl, OpVT, Op);
  }

  // Issue a bsf (scan bits forward) which also sets EFLAGS.
  SDVTList VTs = DAG.getVTList(OpVT, MVT::i32);
  Op = DAG.getNode(X86ISD::BSF, dl, VTs, Op);

  // If src is zero (i.e. bsf sets ZF), returns NumBits.
  SmallVector<SDValue, 4> Ops;
  Ops.push_back(Op);
  Ops.push_back(DAG.getConstant(NumBits, OpVT));
  Ops.push_back(DAG.getConstant(X86::COND_E, MVT::i8));
  Ops.push_back(Op.getValue(1));
  Op = DAG.getNode(X86ISD::CMOV, dl, OpVT, &Ops[0], 4);

  if (VT == MVT::i8)
    Op = DAG.getNode(ISD::TRUNCATE, dl, MVT::i8, Op);
  return Op;
}

SDValue X86TargetLowering::LowerMUL_V2I64(SDValue Op, SelectionDAG &DAG) {
  MVT VT = Op.getValueType();
  assert(VT == MVT::v2i64 && "Only know how to lower V2I64 multiply");
  DebugLoc dl = Op.getDebugLoc();

  //  ulong2 Ahi = __builtin_ia32_psrlqi128( a, 32);
  //  ulong2 Bhi = __builtin_ia32_psrlqi128( b, 32);
  //  ulong2 AloBlo = __builtin_ia32_pmuludq128( a, b );
  //  ulong2 AloBhi = __builtin_ia32_pmuludq128( a, Bhi );
  //  ulong2 AhiBlo = __builtin_ia32_pmuludq128( Ahi, b );
  //
  //  AloBhi = __builtin_ia32_psllqi128( AloBhi, 32 );
  //  AhiBlo = __builtin_ia32_psllqi128( AhiBlo, 32 );
  //  return AloBlo + AloBhi + AhiBlo;

  SDValue A = Op.getOperand(0);
  SDValue B = Op.getOperand(1);

  SDValue Ahi = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_psrli_q, MVT::i32),
                       A, DAG.getConstant(32, MVT::i32));
  SDValue Bhi = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_psrli_q, MVT::i32),
                       B, DAG.getConstant(32, MVT::i32));
  SDValue AloBlo = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_pmulu_dq, MVT::i32),
                       A, B);
  SDValue AloBhi = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_pmulu_dq, MVT::i32),
                       A, Bhi);
  SDValue AhiBlo = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_pmulu_dq, MVT::i32),
                       Ahi, B);
  AloBhi = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_pslli_q, MVT::i32),
                       AloBhi, DAG.getConstant(32, MVT::i32));
  AhiBlo = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                       DAG.getConstant(Intrinsic::x86_sse2_pslli_q, MVT::i32),
                       AhiBlo, DAG.getConstant(32, MVT::i32));
  SDValue Res = DAG.getNode(ISD::ADD, dl, VT, AloBlo, AloBhi);
  Res = DAG.getNode(ISD::ADD, dl, VT, Res, AhiBlo);
  return Res;
}


SDValue X86TargetLowering::LowerXALUO(SDValue Op, SelectionDAG &DAG) {
  // Lower the "add/sub/mul with overflow" instruction into a regular ins plus
  // a "setcc" instruction that checks the overflow flag. The "brcond" lowering
  // looks for this combo and may remove the "setcc" instruction if the "setcc"
  // has only one use.
  SDNode *N = Op.getNode();
  SDValue LHS = N->getOperand(0);
  SDValue RHS = N->getOperand(1);
  unsigned BaseOp = 0;
  unsigned Cond = 0;
  DebugLoc dl = Op.getDebugLoc();

  switch (Op.getOpcode()) {
  default: llvm_unreachable("Unknown ovf instruction!");
  case ISD::SADDO:
    // A subtract of one will be selected as a INC. Note that INC doesn't
    // set CF, so we can't do this for UADDO.
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
      if (C->getAPIntValue() == 1) {
        BaseOp = X86ISD::INC;
        Cond = X86::COND_O;
        break;
      }
    BaseOp = X86ISD::ADD;
    Cond = X86::COND_O;
    break;
  case ISD::UADDO:
    BaseOp = X86ISD::ADD;
    Cond = X86::COND_B;
    break;
  case ISD::SSUBO:
    // A subtract of one will be selected as a DEC. Note that DEC doesn't
    // set CF, so we can't do this for USUBO.
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
      if (C->getAPIntValue() == 1) {
        BaseOp = X86ISD::DEC;
        Cond = X86::COND_O;
        break;
      }
    BaseOp = X86ISD::SUB;
    Cond = X86::COND_O;
    break;
  case ISD::USUBO:
    BaseOp = X86ISD::SUB;
    Cond = X86::COND_B;
    break;
  case ISD::SMULO:
    BaseOp = X86ISD::SMUL;
    Cond = X86::COND_O;
    break;
  case ISD::UMULO:
    BaseOp = X86ISD::UMUL;
    Cond = X86::COND_B;
    break;
  }

  // Also sets EFLAGS.
  SDVTList VTs = DAG.getVTList(N->getValueType(0), MVT::i32);
  SDValue Sum = DAG.getNode(BaseOp, dl, VTs, LHS, RHS);

  SDValue SetCC =
    DAG.getNode(X86ISD::SETCC, dl, N->getValueType(1),
                DAG.getConstant(Cond, MVT::i32), SDValue(Sum.getNode(), 1));

  DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), SetCC);
  return Sum;
}

SDValue X86TargetLowering::LowerCMP_SWAP(SDValue Op, SelectionDAG &DAG) {
  MVT T = Op.getValueType();
  DebugLoc dl = Op.getDebugLoc();
  unsigned Reg = 0;
  unsigned size = 0;
  switch(T.getSimpleVT()) {
  default:
    assert(false && "Invalid value type!");
  case MVT::i8:  Reg = X86::AL;  size = 1; break;
  case MVT::i16: Reg = X86::AX;  size = 2; break;
  case MVT::i32: Reg = X86::EAX; size = 4; break;
  case MVT::i64:
    assert(Subtarget->is64Bit() && "Node not type legal!");
    Reg = X86::RAX; size = 8;
    break;
  }
  SDValue cpIn = DAG.getCopyToReg(Op.getOperand(0), dl, Reg,
                                    Op.getOperand(2), SDValue());
  SDValue Ops[] = { cpIn.getValue(0),
                    Op.getOperand(1),
                    Op.getOperand(3),
                    DAG.getTargetConstant(size, MVT::i8),
                    cpIn.getValue(1) };
  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
  SDValue Result = DAG.getNode(X86ISD::LCMPXCHG_DAG, dl, Tys, Ops, 5);
  SDValue cpOut =
    DAG.getCopyFromReg(Result.getValue(0), dl, Reg, T, Result.getValue(1));
  return cpOut;
}

SDValue X86TargetLowering::LowerREADCYCLECOUNTER(SDValue Op,
                                                 SelectionDAG &DAG) {
  assert(Subtarget->is64Bit() && "Result not type legalized?");
  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
  SDValue TheChain = Op.getOperand(0);
  DebugLoc dl = Op.getDebugLoc();
  SDValue rd = DAG.getNode(X86ISD::RDTSC_DAG, dl, Tys, &TheChain, 1);
  SDValue rax = DAG.getCopyFromReg(rd, dl, X86::RAX, MVT::i64, rd.getValue(1));
  SDValue rdx = DAG.getCopyFromReg(rax.getValue(1), dl, X86::RDX, MVT::i64,
                                   rax.getValue(2));
  SDValue Tmp = DAG.getNode(ISD::SHL, dl, MVT::i64, rdx,
                            DAG.getConstant(32, MVT::i8));
  SDValue Ops[] = {
    DAG.getNode(ISD::OR, dl, MVT::i64, rax, Tmp),
    rdx.getValue(1)
  };
  return DAG.getMergeValues(Ops, 2, dl);
}

SDValue X86TargetLowering::LowerLOAD_SUB(SDValue Op, SelectionDAG &DAG) {
  SDNode *Node = Op.getNode();
  DebugLoc dl = Node->getDebugLoc();
  MVT T = Node->getValueType(0);
  SDValue negOp = DAG.getNode(ISD::SUB, dl, T,
                              DAG.getConstant(0, T), Node->getOperand(2));
  return DAG.getAtomic(ISD::ATOMIC_LOAD_ADD, dl,
                       cast<AtomicSDNode>(Node)->getMemoryVT(),
                       Node->getOperand(0),
                       Node->getOperand(1), negOp,
                       cast<AtomicSDNode>(Node)->getSrcValue(),
                       cast<AtomicSDNode>(Node)->getAlignment());
}

/// LowerOperation - Provide custom lowering hooks for some operations.
///
SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
  switch (Op.getOpcode()) {
  default: llvm_unreachable("Should not custom lower this!");
  case ISD::ATOMIC_CMP_SWAP:    return LowerCMP_SWAP(Op,DAG);
  case ISD::ATOMIC_LOAD_SUB:    return LowerLOAD_SUB(Op,DAG);
  case ISD::BUILD_VECTOR:       return LowerBUILD_VECTOR(Op, DAG);
  case ISD::VECTOR_SHUFFLE:     return LowerVECTOR_SHUFFLE(Op, DAG);
  case ISD::EXTRACT_VECTOR_ELT: return LowerEXTRACT_VECTOR_ELT(Op, DAG);
  case ISD::INSERT_VECTOR_ELT:  return LowerINSERT_VECTOR_ELT(Op, DAG);
  case ISD::SCALAR_TO_VECTOR:   return LowerSCALAR_TO_VECTOR(Op, DAG);
  case ISD::ConstantPool:       return LowerConstantPool(Op, DAG);
  case ISD::GlobalAddress:      return LowerGlobalAddress(Op, DAG);
  case ISD::GlobalTLSAddress:   return LowerGlobalTLSAddress(Op, DAG);
  case ISD::ExternalSymbol:     return LowerExternalSymbol(Op, DAG);
  case ISD::SHL_PARTS:
  case ISD::SRA_PARTS:
  case ISD::SRL_PARTS:          return LowerShift(Op, DAG);
  case ISD::SINT_TO_FP:         return LowerSINT_TO_FP(Op, DAG);
  case ISD::UINT_TO_FP:         return LowerUINT_TO_FP(Op, DAG);
  case ISD::FP_TO_SINT:         return LowerFP_TO_SINT(Op, DAG);
  case ISD::FP_TO_UINT:         return LowerFP_TO_UINT(Op, DAG);
  case ISD::FABS:               return LowerFABS(Op, DAG);
  case ISD::FNEG:               return LowerFNEG(Op, DAG);
  case ISD::FCOPYSIGN:          return LowerFCOPYSIGN(Op, DAG);
  case ISD::SETCC:              return LowerSETCC(Op, DAG);
  case ISD::VSETCC:             return LowerVSETCC(Op, DAG);
  case ISD::SELECT:             return LowerSELECT(Op, DAG);
  case ISD::BRCOND:             return LowerBRCOND(Op, DAG);
  case ISD::JumpTable:          return LowerJumpTable(Op, DAG);
  case ISD::CALL:               return LowerCALL(Op, DAG);
  case ISD::RET:                return LowerRET(Op, DAG);
  case ISD::FORMAL_ARGUMENTS:   return LowerFORMAL_ARGUMENTS(Op, DAG);
  case ISD::VASTART:            return LowerVASTART(Op, DAG);
  case ISD::VAARG:              return LowerVAARG(Op, DAG);
  case ISD::VACOPY:             return LowerVACOPY(Op, DAG);
  case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
  case ISD::RETURNADDR:         return LowerRETURNADDR(Op, DAG);
  case ISD::FRAMEADDR:          return LowerFRAMEADDR(Op, DAG);
  case ISD::FRAME_TO_ARGS_OFFSET:
                                return LowerFRAME_TO_ARGS_OFFSET(Op, DAG);
  case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
  case ISD::EH_RETURN:          return LowerEH_RETURN(Op, DAG);
  case ISD::TRAMPOLINE:         return LowerTRAMPOLINE(Op, DAG);
  case ISD::FLT_ROUNDS_:        return LowerFLT_ROUNDS_(Op, DAG);
  case ISD::CTLZ:               return LowerCTLZ(Op, DAG);
  case ISD::CTTZ:               return LowerCTTZ(Op, DAG);
  case ISD::MUL:                return LowerMUL_V2I64(Op, DAG);
  case ISD::SADDO:
  case ISD::UADDO:
  case ISD::SSUBO:
  case ISD::USUBO:
  case ISD::SMULO:
  case ISD::UMULO:              return LowerXALUO(Op, DAG);
  case ISD::READCYCLECOUNTER:   return LowerREADCYCLECOUNTER(Op, DAG);
  }
}

void X86TargetLowering::
ReplaceATOMIC_BINARY_64(SDNode *Node, SmallVectorImpl<SDValue>&Results,
                        SelectionDAG &DAG, unsigned NewOp) {
  MVT T = Node->getValueType(0);
  DebugLoc dl = Node->getDebugLoc();
  assert (T == MVT::i64 && "Only know how to expand i64 atomics");

  SDValue Chain = Node->getOperand(0);
  SDValue In1 = Node->getOperand(1);
  SDValue In2L = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
                             Node->getOperand(2), DAG.getIntPtrConstant(0));
  SDValue In2H = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
                             Node->getOperand(2), DAG.getIntPtrConstant(1));
  // This is a generalized SDNode, not an AtomicSDNode, so it doesn't
  // have a MemOperand.  Pass the info through as a normal operand.
  SDValue LSI = DAG.getMemOperand(cast<MemSDNode>(Node)->getMemOperand());
  SDValue Ops[] = { Chain, In1, In2L, In2H, LSI };
  SDVTList Tys = DAG.getVTList(MVT::i32, MVT::i32, MVT::Other);
  SDValue Result = DAG.getNode(NewOp, dl, Tys, Ops, 5);
  SDValue OpsF[] = { Result.getValue(0), Result.getValue(1)};
  Results.push_back(DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i64, OpsF, 2));
  Results.push_back(Result.getValue(2));
}

/// ReplaceNodeResults - Replace a node with an illegal result type
/// with a new node built out of custom code.
void X86TargetLowering::ReplaceNodeResults(SDNode *N,
                                           SmallVectorImpl<SDValue>&Results,
                                           SelectionDAG &DAG) {
  DebugLoc dl = N->getDebugLoc();
  switch (N->getOpcode()) {
  default:
    assert(false && "Do not know how to custom type legalize this operation!");
    return;
  case ISD::FP_TO_SINT: {
    std::pair<SDValue,SDValue> Vals =
        FP_TO_INTHelper(SDValue(N, 0), DAG, true);
    SDValue FIST = Vals.first, StackSlot = Vals.second;
    if (FIST.getNode() != 0) {
      MVT VT = N->getValueType(0);
      // Return a load from the stack slot.
      Results.push_back(DAG.getLoad(VT, dl, FIST, StackSlot, NULL, 0));
    }
    return;
  }
  case ISD::READCYCLECOUNTER: {
    SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
    SDValue TheChain = N->getOperand(0);
    SDValue rd = DAG.getNode(X86ISD::RDTSC_DAG, dl, Tys, &TheChain, 1);
    SDValue eax = DAG.getCopyFromReg(rd, dl, X86::EAX, MVT::i32,
                                     rd.getValue(1));
    SDValue edx = DAG.getCopyFromReg(eax.getValue(1), dl, X86::EDX, MVT::i32,
                                     eax.getValue(2));
    // Use a buildpair to merge the two 32-bit values into a 64-bit one.
    SDValue Ops[] = { eax, edx };
    Results.push_back(DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i64, Ops, 2));
    Results.push_back(edx.getValue(1));
    return;
  }
  case ISD::ATOMIC_CMP_SWAP: {
    MVT T = N->getValueType(0);
    assert (T == MVT::i64 && "Only know how to expand i64 Cmp and Swap");
    SDValue cpInL, cpInH;
    cpInL = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, N->getOperand(2),
                        DAG.getConstant(0, MVT::i32));
    cpInH = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, N->getOperand(2),
                        DAG.getConstant(1, MVT::i32));
    cpInL = DAG.getCopyToReg(N->getOperand(0), dl, X86::EAX, cpInL, SDValue());
    cpInH = DAG.getCopyToReg(cpInL.getValue(0), dl, X86::EDX, cpInH,
                             cpInL.getValue(1));
    SDValue swapInL, swapInH;
    swapInL = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, N->getOperand(3),
                          DAG.getConstant(0, MVT::i32));
    swapInH = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, N->getOperand(3),
                          DAG.getConstant(1, MVT::i32));
    swapInL = DAG.getCopyToReg(cpInH.getValue(0), dl, X86::EBX, swapInL,
                               cpInH.getValue(1));
    swapInH = DAG.getCopyToReg(swapInL.getValue(0), dl, X86::ECX, swapInH,
                               swapInL.getValue(1));
    SDValue Ops[] = { swapInH.getValue(0),
                      N->getOperand(1),
                      swapInH.getValue(1) };
    SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
    SDValue Result = DAG.getNode(X86ISD::LCMPXCHG8_DAG, dl, Tys, Ops, 3);
    SDValue cpOutL = DAG.getCopyFromReg(Result.getValue(0), dl, X86::EAX,
                                        MVT::i32, Result.getValue(1));
    SDValue cpOutH = DAG.getCopyFromReg(cpOutL.getValue(1), dl, X86::EDX,
                                        MVT::i32, cpOutL.getValue(2));
    SDValue OpsF[] = { cpOutL.getValue(0), cpOutH.getValue(0)};
    Results.push_back(DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i64, OpsF, 2));
    Results.push_back(cpOutH.getValue(1));
    return;
  }
  case ISD::ATOMIC_LOAD_ADD:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMADD64_DAG);
    return;
  case ISD::ATOMIC_LOAD_AND:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMAND64_DAG);
    return;
  case ISD::ATOMIC_LOAD_NAND:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMNAND64_DAG);
    return;
  case ISD::ATOMIC_LOAD_OR:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMOR64_DAG);
    return;
  case ISD::ATOMIC_LOAD_SUB:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMSUB64_DAG);
    return;
  case ISD::ATOMIC_LOAD_XOR:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMXOR64_DAG);
    return;
  case ISD::ATOMIC_SWAP:
    ReplaceATOMIC_BINARY_64(N, Results, DAG, X86ISD::ATOMSWAP64_DAG);
    return;
  }
}

const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
  switch (Opcode) {
  default: return NULL;
  case X86ISD::BSF:                return "X86ISD::BSF";
  case X86ISD::BSR:                return "X86ISD::BSR";
  case X86ISD::SHLD:               return "X86ISD::SHLD";
  case X86ISD::SHRD:               return "X86ISD::SHRD";
  case X86ISD::FAND:               return "X86ISD::FAND";
  case X86ISD::FOR:                return "X86ISD::FOR";
  case X86ISD::FXOR:               return "X86ISD::FXOR";
  case X86ISD::FSRL:               return "X86ISD::FSRL";
  case X86ISD::FILD:               return "X86ISD::FILD";
  case X86ISD::FILD_FLAG:          return "X86ISD::FILD_FLAG";
  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::CALL:               return "X86ISD::CALL";
  case X86ISD::TAILCALL:           return "X86ISD::TAILCALL";
  case X86ISD::RDTSC_DAG:          return "X86ISD::RDTSC_DAG";
  case X86ISD::BT:                 return "X86ISD::BT";
  case X86ISD::CMP:                return "X86ISD::CMP";
  case X86ISD::COMI:               return "X86ISD::COMI";
  case X86ISD::UCOMI:              return "X86ISD::UCOMI";
  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::REP_STOS";
  case X86ISD::REP_MOVS:           return "X86ISD::REP_MOVS";
  case X86ISD::GlobalBaseReg:      return "X86ISD::GlobalBaseReg";
  case X86ISD::Wrapper:            return "X86ISD::Wrapper";
  case X86ISD::WrapperRIP:         return "X86ISD::WrapperRIP";
  case X86ISD::PEXTRB:             return "X86ISD::PEXTRB";
  case X86ISD::PEXTRW:             return "X86ISD::PEXTRW";
  case X86ISD::INSERTPS:           return "X86ISD::INSERTPS";
  case X86ISD::PINSRB:             return "X86ISD::PINSRB";
  case X86ISD::PINSRW:             return "X86ISD::PINSRW";
  case X86ISD::PSHUFB:             return "X86ISD::PSHUFB";
  case X86ISD::FMAX:               return "X86ISD::FMAX";
  case X86ISD::FMIN:               return "X86ISD::FMIN";
  case X86ISD::FRSQRT:             return "X86ISD::FRSQRT";
  case X86ISD::FRCP:               return "X86ISD::FRCP";
  case X86ISD::TLSADDR:            return "X86ISD::TLSADDR";
  case X86ISD::SegmentBaseAddress: return "X86ISD::SegmentBaseAddress";
  case X86ISD::EH_RETURN:          return "X86ISD::EH_RETURN";
  case X86ISD::TC_RETURN:          return "X86ISD::TC_RETURN";
  case X86ISD::FNSTCW16m:          return "X86ISD::FNSTCW16m";
  case X86ISD::LCMPXCHG_DAG:       return "X86ISD::LCMPXCHG_DAG";
  case X86ISD::LCMPXCHG8_DAG:      return "X86ISD::LCMPXCHG8_DAG";
  case X86ISD::ATOMADD64_DAG:      return "X86ISD::ATOMADD64_DAG";
  case X86ISD::ATOMSUB64_DAG:      return "X86ISD::ATOMSUB64_DAG";
  case X86ISD::ATOMOR64_DAG:       return "X86ISD::ATOMOR64_DAG";
  case X86ISD::ATOMXOR64_DAG:      return "X86ISD::ATOMXOR64_DAG";
  case X86ISD::ATOMAND64_DAG:      return "X86ISD::ATOMAND64_DAG";
  case X86ISD::ATOMNAND64_DAG:     return "X86ISD::ATOMNAND64_DAG";
  case X86ISD::VZEXT_MOVL:         return "X86ISD::VZEXT_MOVL";
  case X86ISD::VZEXT_LOAD:         return "X86ISD::VZEXT_LOAD";
  case X86ISD::VSHL:               return "X86ISD::VSHL";
  case X86ISD::VSRL:               return "X86ISD::VSRL";
  case X86ISD::CMPPD:              return "X86ISD::CMPPD";
  case X86ISD::CMPPS:              return "X86ISD::CMPPS";
  case X86ISD::PCMPEQB:            return "X86ISD::PCMPEQB";
  case X86ISD::PCMPEQW:            return "X86ISD::PCMPEQW";
  case X86ISD::PCMPEQD:            return "X86ISD::PCMPEQD";
  case X86ISD::PCMPEQQ:            return "X86ISD::PCMPEQQ";
  case X86ISD::PCMPGTB:            return "X86ISD::PCMPGTB";
  case X86ISD::PCMPGTW:            return "X86ISD::PCMPGTW";
  case X86ISD::PCMPGTD:            return "X86ISD::PCMPGTD";
  case X86ISD::PCMPGTQ:            return "X86ISD::PCMPGTQ";
  case X86ISD::ADD:                return "X86ISD::ADD";
  case X86ISD::SUB:                return "X86ISD::SUB";
  case X86ISD::SMUL:               return "X86ISD::SMUL";
  case X86ISD::UMUL:               return "X86ISD::UMUL";
  case X86ISD::INC:                return "X86ISD::INC";
  case X86ISD::DEC:                return "X86ISD::DEC";
  case X86ISD::MUL_IMM:            return "X86ISD::MUL_IMM";
  case X86ISD::PTEST:              return "X86ISD::PTEST";
  }
}

// isLegalAddressingMode - Return true if the addressing mode represented
// by AM is legal for this target, for a load/store of the specified type.
bool X86TargetLowering::isLegalAddressingMode(const AddrMode &AM,
                                              const Type *Ty) const {
  // X86 supports extremely general addressing modes.

  // X86 allows a sign-extended 32-bit immediate field as a displacement.
  if (AM.BaseOffs <= -(1LL << 32) || AM.BaseOffs >= (1LL << 32)-1)
    return false;

  if (AM.BaseGV) {
    unsigned GVFlags =
      Subtarget->ClassifyGlobalReference(AM.BaseGV, getTargetMachine());
    
    // If a reference to this global requires an extra load, we can't fold it.
    if (isGlobalStubReference(GVFlags))
      return false;
    
    // If BaseGV requires a register for the PIC base, we cannot also have a
    // BaseReg specified.
    if (AM.HasBaseReg && isGlobalRelativeToPICBase(GVFlags))
      return false;

    // X86-64 only supports addr of globals in small code model.
    if (Subtarget->is64Bit()) {
      if (getTargetMachine().getCodeModel() != CodeModel::Small)
        return false;
      // If lower 4G is not available, then we must use rip-relative addressing.
      if (AM.BaseOffs || AM.Scale > 1)
        return false;
    }
  }

  switch (AM.Scale) {
  case 0:
  case 1:
  case 2:
  case 4:
  case 8:
    // These scales always work.
    break;
  case 3:
  case 5:
  case 9:
    // These scales are formed with basereg+scalereg.  Only accept if there is
    // no basereg yet.
    if (AM.HasBaseReg)
      return false;
    break;
  default:  // Other stuff never works.
    return false;
  }

  return true;
}


bool X86TargetLowering::isTruncateFree(const Type *Ty1, const Type *Ty2) const {
  if (!Ty1->isInteger() || !Ty2->isInteger())
    return false;
  unsigned NumBits1 = Ty1->getPrimitiveSizeInBits();
  unsigned NumBits2 = Ty2->getPrimitiveSizeInBits();
  if (NumBits1 <= NumBits2)
    return false;
  return Subtarget->is64Bit() || NumBits1 < 64;
}

bool X86TargetLowering::isTruncateFree(MVT VT1, MVT VT2) const {
  if (!VT1.isInteger() || !VT2.isInteger())
    return false;
  unsigned NumBits1 = VT1.getSizeInBits();
  unsigned NumBits2 = VT2.getSizeInBits();
  if (NumBits1 <= NumBits2)
    return false;
  return Subtarget->is64Bit() || NumBits1 < 64;
}

bool X86TargetLowering::isZExtFree(const Type *Ty1, const Type *Ty2) const {
  // x86-64 implicitly zero-extends 32-bit results in 64-bit registers.
  return Ty1 == Type::Int32Ty && Ty2 == Type::Int64Ty && Subtarget->is64Bit();
}

bool X86TargetLowering::isZExtFree(MVT VT1, MVT VT2) const {
  // x86-64 implicitly zero-extends 32-bit results in 64-bit registers.
  return VT1 == MVT::i32 && VT2 == MVT::i64 && Subtarget->is64Bit();
}

bool X86TargetLowering::isNarrowingProfitable(MVT VT1, MVT VT2) const {
  // i16 instructions are longer (0x66 prefix) and potentially slower.
  return !(VT1 == MVT::i32 && VT2 == MVT::i16);
}

/// 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(const SmallVectorImpl<int> &M, 
                                      MVT VT) const {
  // Only do shuffles on 128-bit vector types for now.
  if (VT.getSizeInBits() == 64)
    return false;

  // FIXME: pshufb, blends, palignr, shifts.
  return (VT.getVectorNumElements() == 2 ||
          ShuffleVectorSDNode::isSplatMask(&M[0], VT) ||
          isMOVLMask(M, VT) ||
          isSHUFPMask(M, VT) ||
          isPSHUFDMask(M, VT) ||
          isPSHUFHWMask(M, VT) ||
          isPSHUFLWMask(M, VT) ||
          isUNPCKLMask(M, VT) ||
          isUNPCKHMask(M, VT) ||
          isUNPCKL_v_undef_Mask(M, VT) ||
          isUNPCKH_v_undef_Mask(M, VT));
}

bool
X86TargetLowering::isVectorClearMaskLegal(const SmallVectorImpl<int> &Mask,
                                          MVT VT) const {
  unsigned NumElts = VT.getVectorNumElements();
  // FIXME: This collection of masks seems suspect.
  if (NumElts == 2)
    return true;
  if (NumElts == 4 && VT.getSizeInBits() == 128) {
    return (isMOVLMask(Mask, VT)  ||
            isCommutedMOVLMask(Mask, VT, true) ||
            isSHUFPMask(Mask, VT) ||
            isCommutedSHUFPMask(Mask, VT));
  }
  return false;
}

//===----------------------------------------------------------------------===//
//                           X86 Scheduler Hooks
//===----------------------------------------------------------------------===//

// private utility function
MachineBasicBlock *
X86TargetLowering::EmitAtomicBitwiseWithCustomInserter(MachineInstr *bInstr,
                                                       MachineBasicBlock *MBB,
                                                       unsigned regOpc,
                                                       unsigned immOpc,
                                                       unsigned LoadOpc,
                                                       unsigned CXchgOpc,
                                                       unsigned copyOpc,
                                                       unsigned notOpc,
                                                       unsigned EAXreg,
                                                       TargetRegisterClass *RC,
                                                       bool invSrc) const {
  // For the atomic bitwise operator, we generate
  //   thisMBB:
  //   newMBB:
  //     ld  t1 = [bitinstr.addr]
  //     op  t2 = t1, [bitinstr.val]
  //     mov EAX = t1
  //     lcs dest = [bitinstr.addr], t2  [EAX is implicit]
  //     bz  newMBB
  //     fallthrough -->nextMBB
  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
  const BasicBlock *LLVM_BB = MBB->getBasicBlock();
  MachineFunction::iterator MBBIter = MBB;
  ++MBBIter;

  /// First build the CFG
  MachineFunction *F = MBB->getParent();
  MachineBasicBlock *thisMBB = MBB;
  MachineBasicBlock *newMBB = F->CreateMachineBasicBlock(LLVM_BB);
  MachineBasicBlock *nextMBB = F->CreateMachineBasicBlock(LLVM_BB);
  F->insert(MBBIter, newMBB);
  F->insert(MBBIter, nextMBB);

  // Move all successors to thisMBB to nextMBB
  nextMBB->transferSuccessors(thisMBB);

  // Update thisMBB to fall through to newMBB
  thisMBB->addSuccessor(newMBB);

  // newMBB jumps to itself and fall through to nextMBB
  newMBB->addSuccessor(nextMBB);
  newMBB->addSuccessor(newMBB);

  // Insert instructions into newMBB based on incoming instruction
  assert(bInstr->getNumOperands() < X86AddrNumOperands + 4 &&
         "unexpected number of operands");
  DebugLoc dl = bInstr->getDebugLoc();
  MachineOperand& destOper = bInstr->getOperand(0);
  MachineOperand* argOpers[2 + X86AddrNumOperands];
  int numArgs = bInstr->getNumOperands() - 1;
  for (int i=0; i < numArgs; ++i)
    argOpers[i] = &bInstr->getOperand(i+1);

  // x86 address has 4 operands: base, index, scale, and displacement
  int lastAddrIndx = X86AddrNumOperands - 1; // [0,3]
  int valArgIndx = lastAddrIndx + 1;

  unsigned t1 = F->getRegInfo().createVirtualRegister(RC);
  MachineInstrBuilder MIB = BuildMI(newMBB, dl, TII->get(LoadOpc), t1);
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);

  unsigned tt = F->getRegInfo().createVirtualRegister(RC);
  if (invSrc) {
    MIB = BuildMI(newMBB, dl, TII->get(notOpc), tt).addReg(t1);
  }
  else
    tt = t1;

  unsigned t2 = F->getRegInfo().createVirtualRegister(RC);
  assert((argOpers[valArgIndx]->isReg() ||
          argOpers[valArgIndx]->isImm()) &&
         "invalid operand");
  if (argOpers[valArgIndx]->isReg())
    MIB = BuildMI(newMBB, dl, TII->get(regOpc), t2);
  else
    MIB = BuildMI(newMBB, dl, TII->get(immOpc), t2);
  MIB.addReg(tt);
  (*MIB).addOperand(*argOpers[valArgIndx]);

  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), EAXreg);
  MIB.addReg(t1);

  MIB = BuildMI(newMBB, dl, TII->get(CXchgOpc));
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);
  MIB.addReg(t2);
  assert(bInstr->hasOneMemOperand() && "Unexpected number of memoperand");
  (*MIB).addMemOperand(*F, *bInstr->memoperands_begin());

  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), destOper.getReg());
  MIB.addReg(EAXreg);

  // insert branch
  BuildMI(newMBB, dl, TII->get(X86::JNE)).addMBB(newMBB);

  F->DeleteMachineInstr(bInstr);   // The pseudo instruction is gone now.
  return nextMBB;
}

// private utility function:  64 bit atomics on 32 bit host.
MachineBasicBlock *
X86TargetLowering::EmitAtomicBit6432WithCustomInserter(MachineInstr *bInstr,
                                                       MachineBasicBlock *MBB,
                                                       unsigned regOpcL,
                                                       unsigned regOpcH,
                                                       unsigned immOpcL,
                                                       unsigned immOpcH,
                                                       bool invSrc) const {
  // For the atomic bitwise operator, we generate
  //   thisMBB (instructions are in pairs, except cmpxchg8b)
  //     ld t1,t2 = [bitinstr.addr]
  //   newMBB:
  //     out1, out2 = phi (thisMBB, t1/t2) (newMBB, t3/t4)
  //     op  t5, t6 <- out1, out2, [bitinstr.val]
  //      (for SWAP, substitute:  mov t5, t6 <- [bitinstr.val])
  //     mov ECX, EBX <- t5, t6
  //     mov EAX, EDX <- t1, t2
  //     cmpxchg8b [bitinstr.addr]  [EAX, EDX, EBX, ECX implicit]
  //     mov t3, t4 <- EAX, EDX
  //     bz  newMBB
  //     result in out1, out2
  //     fallthrough -->nextMBB

  const TargetRegisterClass *RC = X86::GR32RegisterClass;
  const unsigned LoadOpc = X86::MOV32rm;
  const unsigned copyOpc = X86::MOV32rr;
  const unsigned NotOpc = X86::NOT32r;
  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
  const BasicBlock *LLVM_BB = MBB->getBasicBlock();
  MachineFunction::iterator MBBIter = MBB;
  ++MBBIter;

  /// First build the CFG
  MachineFunction *F = MBB->getParent();
  MachineBasicBlock *thisMBB = MBB;
  MachineBasicBlock *newMBB = F->CreateMachineBasicBlock(LLVM_BB);
  MachineBasicBlock *nextMBB = F->CreateMachineBasicBlock(LLVM_BB);
  F->insert(MBBIter, newMBB);
  F->insert(MBBIter, nextMBB);

  // Move all successors to thisMBB to nextMBB
  nextMBB->transferSuccessors(thisMBB);

  // Update thisMBB to fall through to newMBB
  thisMBB->addSuccessor(newMBB);

  // newMBB jumps to itself and fall through to nextMBB
  newMBB->addSuccessor(nextMBB);
  newMBB->addSuccessor(newMBB);

  DebugLoc dl = bInstr->getDebugLoc();
  // Insert instructions into newMBB based on incoming instruction
  // There are 8 "real" operands plus 9 implicit def/uses, ignored here.
  assert(bInstr->getNumOperands() < X86AddrNumOperands + 14 &&
         "unexpected number of operands");
  MachineOperand& dest1Oper = bInstr->getOperand(0);
  MachineOperand& dest2Oper = bInstr->getOperand(1);
  MachineOperand* argOpers[2 + X86AddrNumOperands];
  for (int i=0; i < 2 + X86AddrNumOperands; ++i)
    argOpers[i] = &bInstr->getOperand(i+2);

  // x86 address has 4 operands: base, index, scale, and displacement
  int lastAddrIndx = X86AddrNumOperands - 1; // [0,3]

  unsigned t1 = F->getRegInfo().createVirtualRegister(RC);
  MachineInstrBuilder MIB = BuildMI(thisMBB, dl, TII->get(LoadOpc), t1);
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);
  unsigned t2 = F->getRegInfo().createVirtualRegister(RC);
  MIB = BuildMI(thisMBB, dl, TII->get(LoadOpc), t2);
  // add 4 to displacement.
  for (int i=0; i <= lastAddrIndx-2; ++i)
    (*MIB).addOperand(*argOpers[i]);
  MachineOperand newOp3 = *(argOpers[3]);
  if (newOp3.isImm())
    newOp3.setImm(newOp3.getImm()+4);
  else
    newOp3.setOffset(newOp3.getOffset()+4);
  (*MIB).addOperand(newOp3);
  (*MIB).addOperand(*argOpers[lastAddrIndx]);

  // t3/4 are defined later, at the bottom of the loop
  unsigned t3 = F->getRegInfo().createVirtualRegister(RC);
  unsigned t4 = F->getRegInfo().createVirtualRegister(RC);
  BuildMI(newMBB, dl, TII->get(X86::PHI), dest1Oper.getReg())
    .addReg(t1).addMBB(thisMBB).addReg(t3).addMBB(newMBB);
  BuildMI(newMBB, dl, TII->get(X86::PHI), dest2Oper.getReg())
    .addReg(t2).addMBB(thisMBB).addReg(t4).addMBB(newMBB);

  unsigned tt1 = F->getRegInfo().createVirtualRegister(RC);
  unsigned tt2 = F->getRegInfo().createVirtualRegister(RC);
  if (invSrc) {
    MIB = BuildMI(newMBB, dl, TII->get(NotOpc), tt1).addReg(t1);
    MIB = BuildMI(newMBB, dl, TII->get(NotOpc), tt2).addReg(t2);
  } else {
    tt1 = t1;
    tt2 = t2;
  }

  int valArgIndx = lastAddrIndx + 1;
  assert((argOpers[valArgIndx]->isReg() ||
          argOpers[valArgIndx]->isImm()) &&
         "invalid operand");
  unsigned t5 = F->getRegInfo().createVirtualRegister(RC);
  unsigned t6 = F->getRegInfo().createVirtualRegister(RC);
  if (argOpers[valArgIndx]->isReg())
    MIB = BuildMI(newMBB, dl, TII->get(regOpcL), t5);
  else
    MIB = BuildMI(newMBB, dl, TII->get(immOpcL), t5);
  if (regOpcL != X86::MOV32rr)
    MIB.addReg(tt1);
  (*MIB).addOperand(*argOpers[valArgIndx]);
  assert(argOpers[valArgIndx + 1]->isReg() ==
         argOpers[valArgIndx]->isReg());
  assert(argOpers[valArgIndx + 1]->isImm() ==
         argOpers[valArgIndx]->isImm());
  if (argOpers[valArgIndx + 1]->isReg())
    MIB = BuildMI(newMBB, dl, TII->get(regOpcH), t6);
  else
    MIB = BuildMI(newMBB, dl, TII->get(immOpcH), t6);
  if (regOpcH != X86::MOV32rr)
    MIB.addReg(tt2);
  (*MIB).addOperand(*argOpers[valArgIndx + 1]);

  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), X86::EAX);
  MIB.addReg(t1);
  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), X86::EDX);
  MIB.addReg(t2);

  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), X86::EBX);
  MIB.addReg(t5);
  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), X86::ECX);
  MIB.addReg(t6);

  MIB = BuildMI(newMBB, dl, TII->get(X86::LCMPXCHG8B));
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);

  assert(bInstr->hasOneMemOperand() && "Unexpected number of memoperand");
  (*MIB).addMemOperand(*F, *bInstr->memoperands_begin());

  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), t3);
  MIB.addReg(X86::EAX);
  MIB = BuildMI(newMBB, dl, TII->get(copyOpc), t4);
  MIB.addReg(X86::EDX);

  // insert branch
  BuildMI(newMBB, dl, TII->get(X86::JNE)).addMBB(newMBB);

  F->DeleteMachineInstr(bInstr);   // The pseudo instruction is gone now.
  return nextMBB;
}

// private utility function
MachineBasicBlock *
X86TargetLowering::EmitAtomicMinMaxWithCustomInserter(MachineInstr *mInstr,
                                                      MachineBasicBlock *MBB,
                                                      unsigned cmovOpc) const {
  // For the atomic min/max operator, we generate
  //   thisMBB:
  //   newMBB:
  //     ld t1 = [min/max.addr]
  //     mov t2 = [min/max.val]
  //     cmp  t1, t2
  //     cmov[cond] t2 = t1
  //     mov EAX = t1
  //     lcs dest = [bitinstr.addr], t2  [EAX is implicit]
  //     bz   newMBB
  //     fallthrough -->nextMBB
  //
  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
  const BasicBlock *LLVM_BB = MBB->getBasicBlock();
  MachineFunction::iterator MBBIter = MBB;
  ++MBBIter;

  /// First build the CFG
  MachineFunction *F = MBB->getParent();
  MachineBasicBlock *thisMBB = MBB;
  MachineBasicBlock *newMBB = F->CreateMachineBasicBlock(LLVM_BB);
  MachineBasicBlock *nextMBB = F->CreateMachineBasicBlock(LLVM_BB);
  F->insert(MBBIter, newMBB);
  F->insert(MBBIter, nextMBB);

  // Move all successors to thisMBB to nextMBB
  nextMBB->transferSuccessors(thisMBB);

  // Update thisMBB to fall through to newMBB
  thisMBB->addSuccessor(newMBB);

  // newMBB jumps to newMBB and fall through to nextMBB
  newMBB->addSuccessor(nextMBB);
  newMBB->addSuccessor(newMBB);

  DebugLoc dl = mInstr->getDebugLoc();
  // Insert instructions into newMBB based on incoming instruction
  assert(mInstr->getNumOperands() < X86AddrNumOperands + 4 &&
         "unexpected number of operands");
  MachineOperand& destOper = mInstr->getOperand(0);
  MachineOperand* argOpers[2 + X86AddrNumOperands];
  int numArgs = mInstr->getNumOperands() - 1;
  for (int i=0; i < numArgs; ++i)
    argOpers[i] = &mInstr->getOperand(i+1);

  // x86 address has 4 operands: base, index, scale, and displacement
  int lastAddrIndx = X86AddrNumOperands - 1; // [0,3]
  int valArgIndx = lastAddrIndx + 1;

  unsigned t1 = F->getRegInfo().createVirtualRegister(X86::GR32RegisterClass);
  MachineInstrBuilder MIB = BuildMI(newMBB, dl, TII->get(X86::MOV32rm), t1);
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);

  // We only support register and immediate values
  assert((argOpers[valArgIndx]->isReg() ||
          argOpers[valArgIndx]->isImm()) &&
         "invalid operand");

  unsigned t2 = F->getRegInfo().createVirtualRegister(X86::GR32RegisterClass);
  if (argOpers[valArgIndx]->isReg())
    MIB = BuildMI(newMBB, dl, TII->get(X86::MOV32rr), t2);
  else
    MIB = BuildMI(newMBB, dl, TII->get(X86::MOV32rr), t2);
  (*MIB).addOperand(*argOpers[valArgIndx]);

  MIB = BuildMI(newMBB, dl, TII->get(X86::MOV32rr), X86::EAX);
  MIB.addReg(t1);

  MIB = BuildMI(newMBB, dl, TII->get(X86::CMP32rr));
  MIB.addReg(t1);
  MIB.addReg(t2);

  // Generate movc
  unsigned t3 = F->getRegInfo().createVirtualRegister(X86::GR32RegisterClass);
  MIB = BuildMI(newMBB, dl, TII->get(cmovOpc),t3);
  MIB.addReg(t2);
  MIB.addReg(t1);

  // Cmp and exchange if none has modified the memory location
  MIB = BuildMI(newMBB, dl, TII->get(X86::LCMPXCHG32));
  for (int i=0; i <= lastAddrIndx; ++i)
    (*MIB).addOperand(*argOpers[i]);
  MIB.addReg(t3);
  assert(mInstr->hasOneMemOperand() && "Unexpected number of memoperand");
  (*MIB).addMemOperand(*F, *mInstr->memoperands_begin());

  MIB = BuildMI(newMBB, dl, TII->get(X86::MOV32rr), destOper.getReg());
  MIB.addReg(X86::EAX);

  // insert branch
  BuildMI(newMBB, dl, TII->get(X86::JNE)).addMBB(newMBB);

  F->DeleteMachineInstr(mInstr);   // The pseudo instruction is gone now.
  return nextMBB;
}


MachineBasicBlock *
X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
                                               MachineBasicBlock *BB) const {
  DebugLoc dl = MI->getDebugLoc();
  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
  switch (MI->getOpcode()) {
  default: assert(false && "Unexpected instr type to insert");
  case X86::CMOV_V1I64:
  case X86::CMOV_FR32:
  case X86::CMOV_FR64:
  case X86::CMOV_V4F32:
  case X86::CMOV_V2F64:
  case X86::CMOV_V2I64: {
    // 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();
    MachineFunction::iterator It = BB;
    ++It;

    //  thisMBB:
    //  ...
    //   TrueVal = ...
    //   cmpTY ccX, r1, r2
    //   bCC copy1MBB
    //   fallthrough --> copy0MBB
    MachineBasicBlock *thisMBB = BB;
    MachineFunction *F = BB->getParent();
    MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
    MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
    unsigned Opc =
      X86::GetCondBranchFromCond((X86::CondCode)MI->getOperand(3).getImm());
    BuildMI(BB, dl, TII->get(Opc)).addMBB(sinkMBB);
    F->insert(It, copy0MBB);
    F->insert(It, sinkMBB);
    // Update machine-CFG edges by transferring all successors of the current
    // block to the new block which will contain the Phi node for the select.
    sinkMBB->transferSuccessors(BB);

    // Add the true and fallthrough blocks as its successors.
    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, dl, TII->get(X86::PHI), MI->getOperand(0).getReg())
      .addReg(MI->getOperand(1).getReg()).addMBB(copy0MBB)
      .addReg(MI->getOperand(2).getReg()).addMBB(thisMBB);

    F->DeleteMachineInstr(MI);   // The pseudo instruction is gone now.
    return BB;
  }

  case X86::FP32_TO_INT16_IN_MEM:
  case X86::FP32_TO_INT32_IN_MEM:
  case X86::FP32_TO_INT64_IN_MEM:
  case X86::FP64_TO_INT16_IN_MEM:
  case X86::FP64_TO_INT32_IN_MEM:
  case X86::FP64_TO_INT64_IN_MEM:
  case X86::FP80_TO_INT16_IN_MEM:
  case X86::FP80_TO_INT32_IN_MEM:
  case X86::FP80_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, dl, TII->get(X86::FNSTCW16m)), CWFrameIdx);

    // Load the old value of the high byte of the control word...
    unsigned OldCW =
      F->getRegInfo().createVirtualRegister(X86::GR16RegisterClass);
    addFrameReference(BuildMI(BB, dl, TII->get(X86::MOV16rm), OldCW),
                      CWFrameIdx);

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

    // Reload the modified control word now...
    addFrameReference(BuildMI(BB, dl, TII->get(X86::FLDCW16m)), CWFrameIdx);

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

    // Get the X86 opcode to use.
    unsigned Opc;
    switch (MI->getOpcode()) {
    default: llvm_unreachable("illegal opcode!");
    case X86::FP32_TO_INT16_IN_MEM: Opc = X86::IST_Fp16m32; break;
    case X86::FP32_TO_INT32_IN_MEM: Opc = X86::IST_Fp32m32; break;
    case X86::FP32_TO_INT64_IN_MEM: Opc = X86::IST_Fp64m32; break;
    case X86::FP64_TO_INT16_IN_MEM: Opc = X86::IST_Fp16m64; break;
    case X86::FP64_TO_INT32_IN_MEM: Opc = X86::IST_Fp32m64; break;
    case X86::FP64_TO_INT64_IN_MEM: Opc = X86::IST_Fp64m64; break;
    case X86::FP80_TO_INT16_IN_MEM: Opc = X86::IST_Fp16m80; break;
    case X86::FP80_TO_INT32_IN_MEM: Opc = X86::IST_Fp32m80; break;
    case X86::FP80_TO_INT64_IN_MEM: Opc = X86::IST_Fp64m80; break;
    }

    X86AddressMode AM;
    MachineOperand &Op = MI->getOperand(0);
    if (Op.isReg()) {
      AM.BaseType = X86AddressMode::RegBase;
      AM.Base.Reg = Op.getReg();
    } else {
      AM.BaseType = X86AddressMode::FrameIndexBase;
      AM.Base.FrameIndex = Op.getIndex();
    }
    Op = MI->getOperand(1);
    if (Op.isImm())
      AM.Scale = Op.getImm();
    Op = MI->getOperand(2);
    if (Op.isImm())
      AM.IndexReg = Op.getImm();
    Op = MI->getOperand(3);
    if (Op.isGlobal()) {
      AM.GV = Op.getGlobal();
    } else {
      AM.Disp = Op.getImm();
    }
    addFullAddress(BuildMI(BB, dl, TII->get(Opc)), AM)
                      .addReg(MI->getOperand(X86AddrNumOperands).getReg());

    // Reload the original control word now.
    addFrameReference(BuildMI(BB, dl, TII->get(X86::FLDCW16m)), CWFrameIdx);

    F->DeleteMachineInstr(MI);   // The pseudo instruction is gone now.
    return BB;
  }
  case X86::ATOMAND32:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND32rr,
                                               X86::AND32ri, X86::MOV32rm,
                                               X86::LCMPXCHG32, X86::MOV32rr,
                                               X86::NOT32r, X86::EAX,
                                               X86::GR32RegisterClass);
  case X86::ATOMOR32:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::OR32rr,
                                               X86::OR32ri, X86::MOV32rm,
                                               X86::LCMPXCHG32, X86::MOV32rr,
                                               X86::NOT32r, X86::EAX,
                                               X86::GR32RegisterClass);
  case X86::ATOMXOR32:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::XOR32rr,
                                               X86::XOR32ri, X86::MOV32rm,
                                               X86::LCMPXCHG32, X86::MOV32rr,
                                               X86::NOT32r, X86::EAX,
                                               X86::GR32RegisterClass);
  case X86::ATOMNAND32:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND32rr,
                                               X86::AND32ri, X86::MOV32rm,
                                               X86::LCMPXCHG32, X86::MOV32rr,
                                               X86::NOT32r, X86::EAX,
                                               X86::GR32RegisterClass, true);
  case X86::ATOMMIN32:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVL32rr);
  case X86::ATOMMAX32:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVG32rr);
  case X86::ATOMUMIN32:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVB32rr);
  case X86::ATOMUMAX32:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVA32rr);

  case X86::ATOMAND16:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND16rr,
                                               X86::AND16ri, X86::MOV16rm,
                                               X86::LCMPXCHG16, X86::MOV16rr,
                                               X86::NOT16r, X86::AX,
                                               X86::GR16RegisterClass);
  case X86::ATOMOR16:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::OR16rr,
                                               X86::OR16ri, X86::MOV16rm,
                                               X86::LCMPXCHG16, X86::MOV16rr,
                                               X86::NOT16r, X86::AX,
                                               X86::GR16RegisterClass);
  case X86::ATOMXOR16:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::XOR16rr,
                                               X86::XOR16ri, X86::MOV16rm,
                                               X86::LCMPXCHG16, X86::MOV16rr,
                                               X86::NOT16r, X86::AX,
                                               X86::GR16RegisterClass);
  case X86::ATOMNAND16:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND16rr,
                                               X86::AND16ri, X86::MOV16rm,
                                               X86::LCMPXCHG16, X86::MOV16rr,
                                               X86::NOT16r, X86::AX,
                                               X86::GR16RegisterClass, true);
  case X86::ATOMMIN16:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVL16rr);
  case X86::ATOMMAX16:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVG16rr);
  case X86::ATOMUMIN16:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVB16rr);
  case X86::ATOMUMAX16:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVA16rr);

  case X86::ATOMAND8:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND8rr,
                                               X86::AND8ri, X86::MOV8rm,
                                               X86::LCMPXCHG8, X86::MOV8rr,
                                               X86::NOT8r, X86::AL,
                                               X86::GR8RegisterClass);
  case X86::ATOMOR8:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::OR8rr,
                                               X86::OR8ri, X86::MOV8rm,
                                               X86::LCMPXCHG8, X86::MOV8rr,
                                               X86::NOT8r, X86::AL,
                                               X86::GR8RegisterClass);
  case X86::ATOMXOR8:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::XOR8rr,
                                               X86::XOR8ri, X86::MOV8rm,
                                               X86::LCMPXCHG8, X86::MOV8rr,
                                               X86::NOT8r, X86::AL,
                                               X86::GR8RegisterClass);
  case X86::ATOMNAND8:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND8rr,
                                               X86::AND8ri, X86::MOV8rm,
                                               X86::LCMPXCHG8, X86::MOV8rr,
                                               X86::NOT8r, X86::AL,
                                               X86::GR8RegisterClass, true);
  // FIXME: There are no CMOV8 instructions; MIN/MAX need some other way.
  // This group is for 64-bit host.
  case X86::ATOMAND64:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND64rr,
                                               X86::AND64ri32, X86::MOV64rm,
                                               X86::LCMPXCHG64, X86::MOV64rr,
                                               X86::NOT64r, X86::RAX,
                                               X86::GR64RegisterClass);
  case X86::ATOMOR64:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::OR64rr,
                                               X86::OR64ri32, X86::MOV64rm,
                                               X86::LCMPXCHG64, X86::MOV64rr,
                                               X86::NOT64r, X86::RAX,
                                               X86::GR64RegisterClass);
  case X86::ATOMXOR64:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::XOR64rr,
                                               X86::XOR64ri32, X86::MOV64rm,
                                               X86::LCMPXCHG64, X86::MOV64rr,
                                               X86::NOT64r, X86::RAX,
                                               X86::GR64RegisterClass);
  case X86::ATOMNAND64:
    return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND64rr,
                                               X86::AND64ri32, X86::MOV64rm,
                                               X86::LCMPXCHG64, X86::MOV64rr,
                                               X86::NOT64r, X86::RAX,
                                               X86::GR64RegisterClass, true);
  case X86::ATOMMIN64:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVL64rr);
  case X86::ATOMMAX64:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVG64rr);
  case X86::ATOMUMIN64:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVB64rr);
  case X86::ATOMUMAX64:
    return EmitAtomicMinMaxWithCustomInserter(MI, BB, X86::CMOVA64rr);

  // This group does 64-bit operations on a 32-bit host.
  case X86::ATOMAND6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::AND32rr, X86::AND32rr,
                                               X86::AND32ri, X86::AND32ri,
                                               false);
  case X86::ATOMOR6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::OR32rr, X86::OR32rr,
                                               X86::OR32ri, X86::OR32ri,
                                               false);
  case X86::ATOMXOR6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::XOR32rr, X86::XOR32rr,
                                               X86::XOR32ri, X86::XOR32ri,
                                               false);
  case X86::ATOMNAND6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::AND32rr, X86::AND32rr,
                                               X86::AND32ri, X86::AND32ri,
                                               true);
  case X86::ATOMADD6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::ADD32rr, X86::ADC32rr,
                                               X86::ADD32ri, X86::ADC32ri,
                                               false);
  case X86::ATOMSUB6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::SUB32rr, X86::SBB32rr,
                                               X86::SUB32ri, X86::SBB32ri,
                                               false);
  case X86::ATOMSWAP6432:
    return EmitAtomicBit6432WithCustomInserter(MI, BB,
                                               X86::MOV32rr, X86::MOV32rr,
                                               X86::MOV32ri, X86::MOV32ri,
                                               false);
  }
}

//===----------------------------------------------------------------------===//
//                           X86 Optimization Hooks
//===----------------------------------------------------------------------===//

void X86TargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
                                                       const APInt &Mask,
                                                       APInt &KnownZero,
                                                       APInt &KnownOne,
                                                       const SelectionDAG &DAG,
                                                       unsigned Depth) const {
  unsigned Opc = Op.getOpcode();
  assert((Opc >= ISD::BUILTIN_OP_END ||
          Opc == ISD::INTRINSIC_WO_CHAIN ||
          Opc == ISD::INTRINSIC_W_CHAIN ||
          Opc == ISD::INTRINSIC_VOID) &&
         "Should use MaskedValueIsZero if you don't know whether Op"
         " is a target node!");

  KnownZero = KnownOne = APInt(Mask.getBitWidth(), 0);   // Don't know anything.
  switch (Opc) {
  default: break;
  case X86ISD::ADD:
  case X86ISD::SUB:
  case X86ISD::SMUL:
  case X86ISD::UMUL:
  case X86ISD::INC:
  case X86ISD::DEC:
    // These nodes' second result is a boolean.
    if (Op.getResNo() == 0)
      break;
    // Fallthrough
  case X86ISD::SETCC:
    KnownZero |= APInt::getHighBitsSet(Mask.getBitWidth(),
                                       Mask.getBitWidth() - 1);
    break;
  }
}

/// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
/// node is a GlobalAddress + offset.
bool X86TargetLowering::isGAPlusOffset(SDNode *N,
                                       GlobalValue* &GA, int64_t &Offset) const{
  if (N->getOpcode() == X86ISD::Wrapper) {
    if (isa<GlobalAddressSDNode>(N->getOperand(0))) {
      GA = cast<GlobalAddressSDNode>(N->getOperand(0))->getGlobal();
      Offset = cast<GlobalAddressSDNode>(N->getOperand(0))->getOffset();
      return true;
    }
  }
  return TargetLowering::isGAPlusOffset(N, GA, Offset);
}

static bool isBaseAlignmentOfN(unsigned N, SDNode *Base,
                               const TargetLowering &TLI) {
  GlobalValue *GV;
  int64_t Offset = 0;
  if (TLI.isGAPlusOffset(Base, GV, Offset))
    return (GV->getAlignment() >= N && (Offset % N) == 0);
  // DAG combine handles the stack object case.
  return false;
}

static bool EltsFromConsecutiveLoads(ShuffleVectorSDNode *N, unsigned NumElems,
                                     MVT EVT, LoadSDNode *&LDBase,
                                     unsigned &LastLoadedElt,
                                     SelectionDAG &DAG, MachineFrameInfo *MFI,
                                     const TargetLowering &TLI) {
  LDBase = NULL;
  LastLoadedElt = -1U;
  for (unsigned i = 0; i < NumElems; ++i) {
    if (N->getMaskElt(i) < 0) {
      if (!LDBase)
        return false;
      continue;
    }

    SDValue Elt = DAG.getShuffleScalarElt(N, i);
    if (!Elt.getNode() ||
        (Elt.getOpcode() != ISD::UNDEF && !ISD::isNON_EXTLoad(Elt.getNode())))
      return false;
    if (!LDBase) {
      if (Elt.getNode()->getOpcode() == ISD::UNDEF)
        return false;
      LDBase = cast<LoadSDNode>(Elt.getNode());
      LastLoadedElt = i;
      continue;
    }
    if (Elt.getOpcode() == ISD::UNDEF)
      continue;

    LoadSDNode *LD = cast<LoadSDNode>(Elt);
    if (!TLI.isConsecutiveLoad(LD, LDBase, EVT.getSizeInBits()/8, i, MFI))
      return false;
    LastLoadedElt = i;
  }
  return true;
}

/// PerformShuffleCombine - Combine a vector_shuffle that is equal to
/// build_vector load1, load2, load3, load4, <0, 1, 2, 3> into a 128-bit load
/// if the load addresses are consecutive, non-overlapping, and in the right
/// order.  In the case of v2i64, it will see if it can rewrite the
/// shuffle to be an appropriate build vector so it can take advantage of
// performBuildVectorCombine.
static SDValue PerformShuffleCombine(SDNode *N, SelectionDAG &DAG,
                                     const TargetLowering &TLI) {
  DebugLoc dl = N->getDebugLoc();
  MVT VT = N->getValueType(0);
  MVT EVT = VT.getVectorElementType();
  ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N);
  unsigned NumElems = VT.getVectorNumElements();

  if (VT.getSizeInBits() != 128)
    return SDValue();

  // Try to combine a vector_shuffle into a 128-bit load.
  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
  LoadSDNode *LD = NULL;
  unsigned LastLoadedElt;
  if (!EltsFromConsecutiveLoads(SVN, NumElems, EVT, LD, LastLoadedElt, DAG,
                                MFI, TLI))
    return SDValue();

  if (LastLoadedElt == NumElems - 1) {
    if (isBaseAlignmentOfN(16, LD->getBasePtr().getNode(), TLI))
      return DAG.getLoad(VT, dl, LD->getChain(), LD->getBasePtr(),
                         LD->getSrcValue(), LD->getSrcValueOffset(),
                         LD->isVolatile());
    return DAG.getLoad(VT, dl, LD->getChain(), LD->getBasePtr(),
                       LD->getSrcValue(), LD->getSrcValueOffset(),
                       LD->isVolatile(), LD->getAlignment());
  } else if (NumElems == 4 && LastLoadedElt == 1) {
    SDVTList Tys = DAG.getVTList(MVT::v2i64, MVT::Other);
    SDValue Ops[] = { LD->getChain(), LD->getBasePtr() };
    SDValue ResNode = DAG.getNode(X86ISD::VZEXT_LOAD, dl, Tys, Ops, 2);
    return DAG.getNode(ISD::BIT_CONVERT, dl, VT, ResNode);
  }
  return SDValue();
}

/// PerformSELECTCombine - Do target-specific dag combines on SELECT nodes.
static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG,
                                    const X86Subtarget *Subtarget) {
  DebugLoc DL = N->getDebugLoc();
  SDValue Cond = N->getOperand(0);
  // Get the LHS/RHS of the select.
  SDValue LHS = N->getOperand(1);
  SDValue RHS = N->getOperand(2);
  
  // If we have SSE[12] support, try to form min/max nodes.
  if (Subtarget->hasSSE2() &&
      (LHS.getValueType() == MVT::f32 || LHS.getValueType() == MVT::f64) &&
      Cond.getOpcode() == ISD::SETCC) {
    ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get();

    unsigned Opcode = 0;
    if (LHS == Cond.getOperand(0) && RHS == Cond.getOperand(1)) {
      switch (CC) {
      default: break;
      case ISD::SETOLE: // (X <= Y) ? X : Y -> min
      case ISD::SETULE:
      case ISD::SETLE:
        if (!UnsafeFPMath) break;
        // FALL THROUGH.
      case ISD::SETOLT:  // (X olt/lt Y) ? X : Y -> min
      case ISD::SETLT:
        Opcode = X86ISD::FMIN;
        break;

      case ISD::SETOGT: // (X > Y) ? X : Y -> max
      case ISD::SETUGT:
      case ISD::SETGT:
        if (!UnsafeFPMath) break;
        // FALL THROUGH.
      case ISD::SETUGE:  // (X uge/ge Y) ? X : Y -> max
      case ISD::SETGE:
        Opcode = X86ISD::FMAX;
        break;
      }
    } else if (LHS == Cond.getOperand(1) && RHS == Cond.getOperand(0)) {
      switch (CC) {
      default: break;
      case ISD::SETOGT: // (X > Y) ? Y : X -> min
      case ISD::SETUGT:
      case ISD::SETGT:
        if (!UnsafeFPMath) break;
        // FALL THROUGH.
      case ISD::SETUGE:  // (X uge/ge Y) ? Y : X -> min
      case ISD::SETGE:
        Opcode = X86ISD::FMIN;
        break;

      case ISD::SETOLE:   // (X <= Y) ? Y : X -> max
      case ISD::SETULE:
      case ISD::SETLE:
        if (!UnsafeFPMath) break;
        // FALL THROUGH.
      case ISD::SETOLT:   // (X olt/lt Y) ? Y : X -> max
      case ISD::SETLT:
        Opcode = X86ISD::FMAX;
        break;
      }
    }

    if (Opcode)
      return DAG.getNode(Opcode, DL, N->getValueType(0), LHS, RHS);
  }
  
  // If this is a select between two integer constants, try to do some
  // optimizations.
  if (ConstantSDNode *TrueC = dyn_cast<ConstantSDNode>(LHS)) {
    if (ConstantSDNode *FalseC = dyn_cast<ConstantSDNode>(RHS))
      // Don't do this for crazy integer types.
      if (DAG.getTargetLoweringInfo().isTypeLegal(LHS.getValueType())) {
        // If this is efficiently invertible, canonicalize the LHSC/RHSC values
        // so that TrueC (the true value) is larger than FalseC.
        bool NeedsCondInvert = false;
        
        if (TrueC->getAPIntValue().ult(FalseC->getAPIntValue()) &&
            // Efficiently invertible.
            (Cond.getOpcode() == ISD::SETCC ||  // setcc -> invertible.
             (Cond.getOpcode() == ISD::XOR &&   // xor(X, C) -> invertible.
              isa<ConstantSDNode>(Cond.getOperand(1))))) {
          NeedsCondInvert = true;
          std::swap(TrueC, FalseC);
        }
   
        // Optimize C ? 8 : 0 -> zext(C) << 3.  Likewise for any pow2/0.
        if (FalseC->getAPIntValue() == 0 &&
            TrueC->getAPIntValue().isPowerOf2()) {
          if (NeedsCondInvert) // Invert the condition if needed.
            Cond = DAG.getNode(ISD::XOR, DL, Cond.getValueType(), Cond,
                               DAG.getConstant(1, Cond.getValueType()));
          
          // Zero extend the condition if needed.
          Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, LHS.getValueType(), Cond);
          
          unsigned ShAmt = TrueC->getAPIntValue().logBase2();
          return DAG.getNode(ISD::SHL, DL, LHS.getValueType(), Cond,
                             DAG.getConstant(ShAmt, MVT::i8));
        }
        
        // Optimize Cond ? cst+1 : cst -> zext(setcc(C)+cst.
        if (FalseC->getAPIntValue()+1 == TrueC->getAPIntValue()) {
          if (NeedsCondInvert) // Invert the condition if needed.
            Cond = DAG.getNode(ISD::XOR, DL, Cond.getValueType(), Cond,
                               DAG.getConstant(1, Cond.getValueType()));
          
          // Zero extend the condition if needed.
          Cond = DAG.getNode(ISD::ZERO_EXTEND, DL,
                             FalseC->getValueType(0), Cond);
          return DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond,
                             SDValue(FalseC, 0));
        }
        
        // Optimize cases that will turn into an LEA instruction.  This requires
        // an i32 or i64 and an efficient multiplier (1, 2, 3, 4, 5, 8, 9).
        if (N->getValueType(0) == MVT::i32 || N->getValueType(0) == MVT::i64) {
          uint64_t Diff = TrueC->getZExtValue()-FalseC->getZExtValue();
          if (N->getValueType(0) == MVT::i32) Diff = (unsigned)Diff;
          
          bool isFastMultiplier = false;
          if (Diff < 10) {
            switch ((unsigned char)Diff) {
              default: break;
              case 1:  // result = add base, cond
              case 2:  // result = lea base(    , cond*2)
              case 3:  // result = lea base(cond, cond*2)
              case 4:  // result = lea base(    , cond*4)
              case 5:  // result = lea base(cond, cond*4)
              case 8:  // result = lea base(    , cond*8)
              case 9:  // result = lea base(cond, cond*8)
                isFastMultiplier = true;
                break;
            }
          }
          
          if (isFastMultiplier) {
            APInt Diff = TrueC->getAPIntValue()-FalseC->getAPIntValue();
            if (NeedsCondInvert) // Invert the condition if needed.
              Cond = DAG.getNode(ISD::XOR, DL, Cond.getValueType(), Cond,
                                 DAG.getConstant(1, Cond.getValueType()));
            
            // Zero extend the condition if needed.
            Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, FalseC->getValueType(0),
                               Cond);
            // Scale the condition by the difference.
            if (Diff != 1)
              Cond = DAG.getNode(ISD::MUL, DL, Cond.getValueType(), Cond,
                                 DAG.getConstant(Diff, Cond.getValueType()));
            
            // Add the base if non-zero.
            if (FalseC->getAPIntValue() != 0)
              Cond = DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond,
                                 SDValue(FalseC, 0));
            return Cond;
          }
        }      
      }
  }
      
  return SDValue();
}

/// Optimize X86ISD::CMOV [LHS, RHS, CONDCODE (e.g. X86::COND_NE), CONDVAL]
static SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG,
                                  TargetLowering::DAGCombinerInfo &DCI) {
  DebugLoc DL = N->getDebugLoc();
  
  // If the flag operand isn't dead, don't touch this CMOV.
  if (N->getNumValues() == 2 && !SDValue(N, 1).use_empty())
    return SDValue();
  
  // If this is a select between two integer constants, try to do some
  // optimizations.  Note that the operands are ordered the opposite of SELECT
  // operands.
  if (ConstantSDNode *TrueC = dyn_cast<ConstantSDNode>(N->getOperand(1))) {
    if (ConstantSDNode *FalseC = dyn_cast<ConstantSDNode>(N->getOperand(0))) {
      // Canonicalize the TrueC/FalseC values so that TrueC (the true value) is
      // larger than FalseC (the false value).
      X86::CondCode CC = (X86::CondCode)N->getConstantOperandVal(2);
        
      if (TrueC->getAPIntValue().ult(FalseC->getAPIntValue())) {
        CC = X86::GetOppositeBranchCondition(CC);
        std::swap(TrueC, FalseC);
      }
        
      // Optimize C ? 8 : 0 -> zext(setcc(C)) << 3.  Likewise for any pow2/0.
      // This is efficient for any integer data type (including i8/i16) and
      // shift amount.
      if (FalseC->getAPIntValue() == 0 && TrueC->getAPIntValue().isPowerOf2()) {
        SDValue Cond = N->getOperand(3);
        Cond = DAG.getNode(X86ISD::SETCC, DL, MVT::i8,
                           DAG.getConstant(CC, MVT::i8), Cond);
      
        // Zero extend the condition if needed.
        Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, TrueC->getValueType(0), Cond);
        
        unsigned ShAmt = TrueC->getAPIntValue().logBase2();
        Cond = DAG.getNode(ISD::SHL, DL, Cond.getValueType(), Cond,
                           DAG.getConstant(ShAmt, MVT::i8));
        if (N->getNumValues() == 2)  // Dead flag value?
          return DCI.CombineTo(N, Cond, SDValue());
        return Cond;
      }
      
      // Optimize Cond ? cst+1 : cst -> zext(setcc(C)+cst.  This is efficient
      // for any integer data type, including i8/i16.
      if (FalseC->getAPIntValue()+1 == TrueC->getAPIntValue()) {
        SDValue Cond = N->getOperand(3);
        Cond = DAG.getNode(X86ISD::SETCC, DL, MVT::i8,
                           DAG.getConstant(CC, MVT::i8), Cond);
        
        // Zero extend the condition if needed.
        Cond = DAG.getNode(ISD::ZERO_EXTEND, DL,
                           FalseC->getValueType(0), Cond);
        Cond = DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond,
                           SDValue(FalseC, 0));
        
        if (N->getNumValues() == 2)  // Dead flag value?
          return DCI.CombineTo(N, Cond, SDValue());
        return Cond;
      }
      
      // Optimize cases that will turn into an LEA instruction.  This requires
      // an i32 or i64 and an efficient multiplier (1, 2, 3, 4, 5, 8, 9).
      if (N->getValueType(0) == MVT::i32 || N->getValueType(0) == MVT::i64) {
        uint64_t Diff = TrueC->getZExtValue()-FalseC->getZExtValue();
        if (N->getValueType(0) == MVT::i32) Diff = (unsigned)Diff;
       
        bool isFastMultiplier = false;
        if (Diff < 10) {
          switch ((unsigned char)Diff) {
          default: break;
          case 1:  // result = add base, cond
          case 2:  // result = lea base(    , cond*2)
          case 3:  // result = lea base(cond, cond*2)
          case 4:  // result = lea base(    , cond*4)
          case 5:  // result = lea base(cond, cond*4)
          case 8:  // result = lea base(    , cond*8)
          case 9:  // result = lea base(cond, cond*8)
            isFastMultiplier = true;
            break;
          }
        }
        
        if (isFastMultiplier) {
          APInt Diff = TrueC->getAPIntValue()-FalseC->getAPIntValue();
          SDValue Cond = N->getOperand(3);
          Cond = DAG.getNode(X86ISD::SETCC, DL, MVT::i8,
                             DAG.getConstant(CC, MVT::i8), Cond);
          // Zero extend the condition if needed.
          Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, FalseC->getValueType(0),
                             Cond);
          // Scale the condition by the difference.
          if (Diff != 1)
            Cond = DAG.getNode(ISD::MUL, DL, Cond.getValueType(), Cond,
                               DAG.getConstant(Diff, Cond.getValueType()));

          // Add the base if non-zero.
          if (FalseC->getAPIntValue() != 0)
            Cond = DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond,
                               SDValue(FalseC, 0));
          if (N->getNumValues() == 2)  // Dead flag value?
            return DCI.CombineTo(N, Cond, SDValue());
          return Cond;
        }
      }      
    }
  }
  return SDValue();
}


/// PerformMulCombine - Optimize a single multiply with constant into two
/// in order to implement it with two cheaper instructions, e.g.
/// LEA + SHL, LEA + LEA.
static SDValue PerformMulCombine(SDNode *N, SelectionDAG &DAG,
                                 TargetLowering::DAGCombinerInfo &DCI) {
  if (DAG.getMachineFunction().
      getFunction()->hasFnAttr(Attribute::OptimizeForSize))
    return SDValue();

  if (DCI.isBeforeLegalize() || DCI.isCalledByLegalizer())
    return SDValue();

  MVT VT = N->getValueType(0);
  if (VT != MVT::i64)
    return SDValue();

  ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(1));
  if (!C)
    return SDValue();
  uint64_t MulAmt = C->getZExtValue();
  if (isPowerOf2_64(MulAmt) || MulAmt == 3 || MulAmt == 5 || MulAmt == 9)
    return SDValue();

  uint64_t MulAmt1 = 0;
  uint64_t MulAmt2 = 0;
  if ((MulAmt % 9) == 0) {
    MulAmt1 = 9;
    MulAmt2 = MulAmt / 9;
  } else if ((MulAmt % 5) == 0) {
    MulAmt1 = 5;
    MulAmt2 = MulAmt / 5;
  } else if ((MulAmt % 3) == 0) {
    MulAmt1 = 3;
    MulAmt2 = MulAmt / 3;
  }
  if (MulAmt2 &&
      (isPowerOf2_64(MulAmt2) || MulAmt2 == 3 || MulAmt2 == 5 || MulAmt2 == 9)){
    DebugLoc DL = N->getDebugLoc();

    if (isPowerOf2_64(MulAmt2) &&
        !(N->hasOneUse() && N->use_begin()->getOpcode() == ISD::ADD))
      // If second multiplifer is pow2, issue it first. We want the multiply by
      // 3, 5, or 9 to be folded into the addressing mode unless the lone use
      // is an add.
      std::swap(MulAmt1, MulAmt2);

    SDValue NewMul;
    if (isPowerOf2_64(MulAmt1)) 
      NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0),
                           DAG.getConstant(Log2_64(MulAmt1), MVT::i8));
    else
      NewMul = DAG.getNode(X86ISD::MUL_IMM, DL, VT, N->getOperand(0),
                           DAG.getConstant(MulAmt1, VT));

    if (isPowerOf2_64(MulAmt2)) 
      NewMul = DAG.getNode(ISD::SHL, DL, VT, NewMul,
                           DAG.getConstant(Log2_64(MulAmt2), MVT::i8));
    else 
      NewMul = DAG.getNode(X86ISD::MUL_IMM, DL, VT, NewMul,
                           DAG.getConstant(MulAmt2, VT));

    // Do not add new nodes to DAG combiner worklist.
    DCI.CombineTo(N, NewMul, false);
  }
  return SDValue();
}


/// PerformShiftCombine - Transforms vector shift nodes to use vector shifts
///                       when possible.
static SDValue PerformShiftCombine(SDNode* N, SelectionDAG &DAG,
                                   const X86Subtarget *Subtarget) {
  // On X86 with SSE2 support, we can transform this to a vector shift if
  // all elements are shifted by the same amount.  We can't do this in legalize
  // because the a constant vector is typically transformed to a constant pool
  // so we have no knowledge of the shift amount.
  if (!Subtarget->hasSSE2())
    return SDValue();

  MVT VT = N->getValueType(0);
  if (VT != MVT::v2i64 && VT != MVT::v4i32 && VT != MVT::v8i16)
    return SDValue();

  SDValue ShAmtOp = N->getOperand(1);
  MVT EltVT = VT.getVectorElementType();
  DebugLoc DL = N->getDebugLoc();
  SDValue BaseShAmt;
  if (ShAmtOp.getOpcode() == ISD::BUILD_VECTOR) {
    unsigned NumElts = VT.getVectorNumElements();
    unsigned i = 0;
    for (; i != NumElts; ++i) {
      SDValue Arg = ShAmtOp.getOperand(i);
      if (Arg.getOpcode() == ISD::UNDEF) continue;
      BaseShAmt = Arg;
      break;
    }
    for (; i != NumElts; ++i) {
      SDValue Arg = ShAmtOp.getOperand(i);
      if (Arg.getOpcode() == ISD::UNDEF) continue;
      if (Arg != BaseShAmt) {
        return SDValue();
      }
    }
  } else if (ShAmtOp.getOpcode() == ISD::VECTOR_SHUFFLE &&
             cast<ShuffleVectorSDNode>(ShAmtOp)->isSplat()) {
    BaseShAmt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, ShAmtOp,
                            DAG.getIntPtrConstant(0));
  } else
    return SDValue();

  if (EltVT.bitsGT(MVT::i32))
    BaseShAmt = DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, BaseShAmt);
  else if (EltVT.bitsLT(MVT::i32))
    BaseShAmt = DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i32, BaseShAmt);

  // The shift amount is identical so we can do a vector shift.
  SDValue  ValOp = N->getOperand(0);
  switch (N->getOpcode()) {
  default:
    llvm_unreachable("Unknown shift opcode!");
    break;
  case ISD::SHL:
    if (VT == MVT::v2i64)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_pslli_q, MVT::i32),
                         ValOp, BaseShAmt);
    if (VT == MVT::v4i32)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_pslli_d, MVT::i32),
                         ValOp, BaseShAmt);
    if (VT == MVT::v8i16)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_pslli_w, MVT::i32),
                         ValOp, BaseShAmt);
    break;
  case ISD::SRA:
    if (VT == MVT::v4i32)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_psrai_d, MVT::i32),
                         ValOp, BaseShAmt);
    if (VT == MVT::v8i16)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_psrai_w, MVT::i32),
                         ValOp, BaseShAmt);
    break;
  case ISD::SRL:
    if (VT == MVT::v2i64)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_psrli_q, MVT::i32),
                         ValOp, BaseShAmt);
    if (VT == MVT::v4i32)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_psrli_d, MVT::i32),
                         ValOp, BaseShAmt);
    if (VT ==  MVT::v8i16)
      return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT,
                         DAG.getConstant(Intrinsic::x86_sse2_psrli_w, MVT::i32),
                         ValOp, BaseShAmt);
    break;
  }
  return SDValue();
}

/// PerformSTORECombine - Do target-specific dag combines on STORE nodes.
static SDValue PerformSTORECombine(SDNode *N, SelectionDAG &DAG,
                                   const X86Subtarget *Subtarget) {
  // Turn load->store of MMX types into GPR load/stores.  This avoids clobbering
  // the FP state in cases where an emms may be missing.
  // A preferable solution to the general problem is to figure out the right
  // places to insert EMMS.  This qualifies as a quick hack.

  // Similarly, turn load->store of i64 into double load/stores in 32-bit mode.
  StoreSDNode *St = cast<StoreSDNode>(N);
  MVT VT = St->getValue().getValueType();
  if (VT.getSizeInBits() != 64)
    return SDValue();

  const Function *F = DAG.getMachineFunction().getFunction();
  bool NoImplicitFloatOps = F->hasFnAttr(Attribute::NoImplicitFloat);
  bool F64IsLegal = !UseSoftFloat && !NoImplicitFloatOps 
    && Subtarget->hasSSE2();
  if ((VT.isVector() ||
       (VT == MVT::i64 && F64IsLegal && !Subtarget->is64Bit())) &&
      isa<LoadSDNode>(St->getValue()) &&
      !cast<LoadSDNode>(St->getValue())->isVolatile() &&
      St->getChain().hasOneUse() && !St->isVolatile()) {
    SDNode* LdVal = St->getValue().getNode();
    LoadSDNode *Ld = 0;
    int TokenFactorIndex = -1;
    SmallVector<SDValue, 8> Ops;
    SDNode* ChainVal = St->getChain().getNode();
    // Must be a store of a load.  We currently handle two cases:  the load
    // is a direct child, and it's under an intervening TokenFactor.  It is
    // possible to dig deeper under nested TokenFactors.
    if (ChainVal == LdVal)
      Ld = cast<LoadSDNode>(St->getChain());
    else if (St->getValue().hasOneUse() &&
             ChainVal->getOpcode() == ISD::TokenFactor) {
      for (unsigned i=0, e = ChainVal->getNumOperands(); i != e; ++i) {
        if (ChainVal->getOperand(i).getNode() == LdVal) {
          TokenFactorIndex = i;
          Ld = cast<LoadSDNode>(St->getValue());
        } else
          Ops.push_back(ChainVal->getOperand(i));
      }
    }

    if (!Ld || !ISD::isNormalLoad(Ld))
      return SDValue();

    // If this is not the MMX case, i.e. we are just turning i64 load/store
    // into f64 load/store, avoid the transformation if there are multiple
    // uses of the loaded value.
    if (!VT.isVector() && !Ld->hasNUsesOfValue(1, 0))
      return SDValue();

    DebugLoc LdDL = Ld->getDebugLoc();
    DebugLoc StDL = N->getDebugLoc();
    // If we are a 64-bit capable x86, lower to a single movq load/store pair.
    // Otherwise, if it's legal to use f64 SSE instructions, use f64 load/store
    // pair instead.
    if (Subtarget->is64Bit() || F64IsLegal) {
      MVT LdVT = Subtarget->is64Bit() ? MVT::i64 : MVT::f64;
      SDValue NewLd = DAG.getLoad(LdVT, LdDL, Ld->getChain(),
                                  Ld->getBasePtr(), Ld->getSrcValue(),
                                  Ld->getSrcValueOffset(), Ld->isVolatile(),
                                  Ld->getAlignment());
      SDValue NewChain = NewLd.getValue(1);
      if (TokenFactorIndex != -1) {
        Ops.push_back(NewChain);
        NewChain = DAG.getNode(ISD::TokenFactor, LdDL, MVT::Other, &Ops[0],
                               Ops.size());
      }
      return DAG.getStore(NewChain, StDL, NewLd, St->getBasePtr(),
                          St->getSrcValue(), St->getSrcValueOffset(),
                          St->isVolatile(), St->getAlignment());
    }

    // Otherwise, lower to two pairs of 32-bit loads / stores.
    SDValue LoAddr = Ld->getBasePtr();
    SDValue HiAddr = DAG.getNode(ISD::ADD, LdDL, MVT::i32, LoAddr,
                                 DAG.getConstant(4, MVT::i32));

    SDValue LoLd = DAG.getLoad(MVT::i32, LdDL, Ld->getChain(), LoAddr,
                               Ld->getSrcValue(), Ld->getSrcValueOffset(),
                               Ld->isVolatile(), Ld->getAlignment());
    SDValue HiLd = DAG.getLoad(MVT::i32, LdDL, Ld->getChain(), HiAddr,
                               Ld->getSrcValue(), Ld->getSrcValueOffset()+4,
                               Ld->isVolatile(),
                               MinAlign(Ld->getAlignment(), 4));

    SDValue NewChain = LoLd.getValue(1);
    if (TokenFactorIndex != -1) {
      Ops.push_back(LoLd);
      Ops.push_back(HiLd);
      NewChain = DAG.getNode(ISD::TokenFactor, LdDL, MVT::Other, &Ops[0],
                             Ops.size());
    }

    LoAddr = St->getBasePtr();
    HiAddr = DAG.getNode(ISD::ADD, StDL, MVT::i32, LoAddr,
                         DAG.getConstant(4, MVT::i32));

    SDValue LoSt = DAG.getStore(NewChain, StDL, LoLd, LoAddr,
                                St->getSrcValue(), St->getSrcValueOffset(),
                                St->isVolatile(), St->getAlignment());
    SDValue HiSt = DAG.getStore(NewChain, StDL, HiLd, HiAddr,
                                St->getSrcValue(),
                                St->getSrcValueOffset() + 4,
                                St->isVolatile(),
                                MinAlign(St->getAlignment(), 4));
    return DAG.getNode(ISD::TokenFactor, StDL, MVT::Other, LoSt, HiSt);
  }
  return SDValue();
}

/// PerformFORCombine - Do target-specific dag combines on X86ISD::FOR and
/// X86ISD::FXOR nodes.
static SDValue PerformFORCombine(SDNode *N, SelectionDAG &DAG) {
  assert(N->getOpcode() == X86ISD::FOR || N->getOpcode() == X86ISD::FXOR);
  // F[X]OR(0.0, x) -> x
  // F[X]OR(x, 0.0) -> x
  if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
    if (C->getValueAPF().isPosZero())
      return N->getOperand(1);
  if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(1)))
    if (C->getValueAPF().isPosZero())
      return N->getOperand(0);
  return SDValue();
}

/// PerformFANDCombine - Do target-specific dag combines on X86ISD::FAND nodes.
static SDValue PerformFANDCombine(SDNode *N, SelectionDAG &DAG) {
  // FAND(0.0, x) -> 0.0
  // FAND(x, 0.0) -> 0.0
  if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
    if (C->getValueAPF().isPosZero())
      return N->getOperand(0);
  if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(1)))
    if (C->getValueAPF().isPosZero())
      return N->getOperand(1);
  return SDValue();
}

static SDValue PerformBTCombine(SDNode *N,
                                SelectionDAG &DAG,
                                TargetLowering::DAGCombinerInfo &DCI) {
  // BT ignores high bits in the bit index operand.
  SDValue Op1 = N->getOperand(1);
  if (Op1.hasOneUse()) {
    unsigned BitWidth = Op1.getValueSizeInBits();
    APInt DemandedMask = APInt::getLowBitsSet(BitWidth, Log2_32(BitWidth));
    APInt KnownZero, KnownOne;
    TargetLowering::TargetLoweringOpt TLO(DAG);
    TargetLowering &TLI = DAG.getTargetLoweringInfo();
    if (TLO.ShrinkDemandedConstant(Op1, DemandedMask) ||
        TLI.SimplifyDemandedBits(Op1, DemandedMask, KnownZero, KnownOne, TLO))
      DCI.CommitTargetLoweringOpt(TLO);
  }
  return SDValue();
}

static SDValue PerformVZEXT_MOVLCombine(SDNode *N, SelectionDAG &DAG) {
  SDValue Op = N->getOperand(0);
  if (Op.getOpcode() == ISD::BIT_CONVERT)
    Op = Op.getOperand(0);
  MVT VT = N->getValueType(0), OpVT = Op.getValueType();
  if (Op.getOpcode() == X86ISD::VZEXT_LOAD &&
      VT.getVectorElementType().getSizeInBits() == 
      OpVT.getVectorElementType().getSizeInBits()) {
    return DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), VT, Op);
  }
  return SDValue();
}

// On X86 and X86-64, atomic operations are lowered to locked instructions.
// Locked instructions, in turn, have implicit fence semantics (all memory
// operations are flushed before issuing the locked instruction, and the
// are not buffered), so we can fold away the common pattern of 
// fence-atomic-fence.
static SDValue PerformMEMBARRIERCombine(SDNode* N, SelectionDAG &DAG) {
  SDValue atomic = N->getOperand(0);
  switch (atomic.getOpcode()) {
    case ISD::ATOMIC_CMP_SWAP:
    case ISD::ATOMIC_SWAP:
    case ISD::ATOMIC_LOAD_ADD:
    case ISD::ATOMIC_LOAD_SUB:
    case ISD::ATOMIC_LOAD_AND:
    case ISD::ATOMIC_LOAD_OR:
    case ISD::ATOMIC_LOAD_XOR:
    case ISD::ATOMIC_LOAD_NAND:
    case ISD::ATOMIC_LOAD_MIN:
    case ISD::ATOMIC_LOAD_MAX:
    case ISD::ATOMIC_LOAD_UMIN:
    case ISD::ATOMIC_LOAD_UMAX:
      break;
    default:
      return SDValue();
  }
  
  SDValue fence = atomic.getOperand(0);
  if (fence.getOpcode() != ISD::MEMBARRIER)
    return SDValue();
  
  switch (atomic.getOpcode()) {
    case ISD::ATOMIC_CMP_SWAP:
      return DAG.UpdateNodeOperands(atomic, fence.getOperand(0),
                                    atomic.getOperand(1), atomic.getOperand(2),
                                    atomic.getOperand(3));
    case ISD::ATOMIC_SWAP:
    case ISD::ATOMIC_LOAD_ADD:
    case ISD::ATOMIC_LOAD_SUB:
    case ISD::ATOMIC_LOAD_AND:
    case ISD::ATOMIC_LOAD_OR:
    case ISD::ATOMIC_LOAD_XOR:
    case ISD::ATOMIC_LOAD_NAND:
    case ISD::ATOMIC_LOAD_MIN:
    case ISD::ATOMIC_LOAD_MAX:
    case ISD::ATOMIC_LOAD_UMIN:
    case ISD::ATOMIC_LOAD_UMAX:
      return DAG.UpdateNodeOperands(atomic, fence.getOperand(0),
                                    atomic.getOperand(1), atomic.getOperand(2));
    default:
      return SDValue();
  }
}

SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
                                             DAGCombinerInfo &DCI) const {
  SelectionDAG &DAG = DCI.DAG;
  switch (N->getOpcode()) {
  default: break;
  case ISD::VECTOR_SHUFFLE: return PerformShuffleCombine(N, DAG, *this);
  case ISD::SELECT:         return PerformSELECTCombine(N, DAG, Subtarget);
  case X86ISD::CMOV:        return PerformCMOVCombine(N, DAG, DCI);
  case ISD::MUL:            return PerformMulCombine(N, DAG, DCI);
  case ISD::SHL:
  case ISD::SRA:
  case ISD::SRL:            return PerformShiftCombine(N, DAG, Subtarget);
  case ISD::STORE:          return PerformSTORECombine(N, DAG, Subtarget);
  case X86ISD::FXOR:
  case X86ISD::FOR:         return PerformFORCombine(N, DAG);
  case X86ISD::FAND:        return PerformFANDCombine(N, DAG);
  case X86ISD::BT:          return PerformBTCombine(N, DAG, DCI);
  case X86ISD::VZEXT_MOVL:  return PerformVZEXT_MOVLCombine(N, DAG);
  case ISD::MEMBARRIER:     return PerformMEMBARRIERCombine(N, DAG);
  }

  return SDValue();
}

//===----------------------------------------------------------------------===//
//                           X86 Inline Assembly Support
//===----------------------------------------------------------------------===//

static bool LowerToBSwap(CallInst *CI) {
  // FIXME: this should verify that we are targetting a 486 or better.  If not,
  // we will turn this bswap into something that will be lowered to logical ops
  // instead of emitting the bswap asm.  For now, we don't support 486 or lower
  // so don't worry about this.
  
  // Verify this is a simple bswap.
  if (CI->getNumOperands() != 2 ||
      CI->getType() != CI->getOperand(1)->getType() ||
      !CI->getType()->isInteger())
    return false;
  
  const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
  if (!Ty || Ty->getBitWidth() % 16 != 0)
    return false;
  
  // Okay, we can do this xform, do so now.
  const Type *Tys[] = { Ty };
  Module *M = CI->getParent()->getParent()->getParent();
  Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
  
  Value *Op = CI->getOperand(1);
  Op = CallInst::Create(Int, Op, CI->getName(), CI);
  
  CI->replaceAllUsesWith(Op);
  CI->eraseFromParent();
  return true;
}

bool X86TargetLowering::ExpandInlineAsm(CallInst *CI) const {
  InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
  std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();

  std::string AsmStr = IA->getAsmString();

  // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
  std::vector<std::string> AsmPieces;
  SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?

  switch (AsmPieces.size()) {
  default: return false;
  case 1:
    AsmStr = AsmPieces[0];
    AsmPieces.clear();
    SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.

    // bswap $0
    if (AsmPieces.size() == 2 &&
        (AsmPieces[0] == "bswap" ||
         AsmPieces[0] == "bswapq" ||
         AsmPieces[0] == "bswapl") &&
        (AsmPieces[1] == "$0" ||
         AsmPieces[1] == "${0:q}")) {
      // No need to check constraints, nothing other than the equivalent of
      // "=r,0" would be valid here.
      return LowerToBSwap(CI);
    }
    // rorw $$8, ${0:w}  -->  llvm.bswap.i16
    if (CI->getType() == Type::Int16Ty &&
        AsmPieces.size() == 3 &&
        AsmPieces[0] == "rorw" &&
        AsmPieces[1] == "$$8," &&
        AsmPieces[2] == "${0:w}" &&
        IA->getConstraintString() == "=r,0,~{dirflag},~{fpsr},~{flags},~{cc}") {
      return LowerToBSwap(CI);
    }
    break;
  case 3:
    if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
        Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
        Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
      // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
      std::vector<std::string> Words;
      SplitString(AsmPieces[0], Words, " \t");
      if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
        Words.clear();
        SplitString(AsmPieces[1], Words, " \t");
        if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
          Words.clear();
          SplitString(AsmPieces[2], Words, " \t,");
          if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
              Words[2] == "%edx") {
            return LowerToBSwap(CI);
          }
        }
      }
    }
    break;
  }
  return false;
}



/// getConstraintType - Given a constraint letter, return the type of
/// constraint it is for this target.
X86TargetLowering::ConstraintType
X86TargetLowering::getConstraintType(const std::string &Constraint) const {
  if (Constraint.size() == 1) {
    switch (Constraint[0]) {
    case 'A':
      return C_Register;
    case 'f':
    case 'r':
    case 'R':
    case 'l':
    case 'q':
    case 'Q':
    case 'x':
    case 'y':
    case 'Y':
      return C_RegisterClass;
    case 'e':
    case 'Z':
      return C_Other;
    default:
      break;
    }
  }
  return TargetLowering::getConstraintType(Constraint);
}

/// LowerXConstraint - try to replace an X constraint, which matches anything,
/// with another that has more specific requirements based on the type of the
/// corresponding operand.
const char *X86TargetLowering::
LowerXConstraint(MVT ConstraintVT) const {
  // FP X constraints get lowered to SSE1/2 registers if available, otherwise
  // 'f' like normal targets.
  if (ConstraintVT.isFloatingPoint()) {
    if (Subtarget->hasSSE2())
      return "Y";
    if (Subtarget->hasSSE1())
      return "x";
  }

  return TargetLowering::LowerXConstraint(ConstraintVT);
}

/// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
/// vector.  If it is invalid, don't add anything to Ops.
void X86TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
                                                     char Constraint,
                                                     bool hasMemory,
                                                     std::vector<SDValue>&Ops,
                                                     SelectionDAG &DAG) const {
  SDValue Result(0, 0);

  switch (Constraint) {
  default: break;
  case 'I':
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      if (C->getZExtValue() <= 31) {
        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
        break;
      }
    }
    return;
  case 'J':
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      if (C->getZExtValue() <= 63) {
        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
        break;
      }
    }
    return;
  case 'K':
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      if ((int8_t)C->getSExtValue() == C->getSExtValue()) {
        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
        break;
      }
    }
    return;
  case 'N':
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      if (C->getZExtValue() <= 255) {
        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
        break;
      }
    }
    return;
  case 'e': {
    // 32-bit signed value
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      const ConstantInt *CI = C->getConstantIntValue();
      if (CI->isValueValidForType(Type::Int32Ty, C->getSExtValue())) {
        // Widen to 64 bits here to get it sign extended.
        Result = DAG.getTargetConstant(C->getSExtValue(), MVT::i64);
        break;
      }
    // FIXME gcc accepts some relocatable values here too, but only in certain
    // memory models; it's complicated.
    }
    return;
  }
  case 'Z': {
    // 32-bit unsigned value
    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
      const ConstantInt *CI = C->getConstantIntValue();
      if (CI->isValueValidForType(Type::Int32Ty, C->getZExtValue())) {
        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
        break;
      }
    }
    // FIXME gcc accepts some relocatable values here too, but only in certain
    // memory models; it's complicated.
    return;
  }
  case 'i': {
    // Literal immediates are always ok.
    if (ConstantSDNode *CST = dyn_cast<ConstantSDNode>(Op)) {
      // Widen to 64 bits here to get it sign extended.
      Result = DAG.getTargetConstant(CST->getSExtValue(), MVT::i64);
      break;
    }

    // If we are in non-pic codegen mode, we allow the address of a global (with
    // an optional displacement) to be used with 'i'.
    GlobalAddressSDNode *GA = 0;
    int64_t Offset = 0;

    // Match either (GA), (GA+C), (GA+C1+C2), etc.
    while (1) {
      if ((GA = dyn_cast<GlobalAddressSDNode>(Op))) {
        Offset += GA->getOffset();
        break;
      } else if (Op.getOpcode() == ISD::ADD) {
        if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
          Offset += C->getZExtValue();
          Op = Op.getOperand(0);
          continue;
        }
      } else if (Op.getOpcode() == ISD::SUB) {
        if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
          Offset += -C->getZExtValue();
          Op = Op.getOperand(0);
          continue;
        }
      }

      // Otherwise, this isn't something we can handle, reject it.
      return;
    }
    
    GlobalValue *GV = GA->getGlobal();
    // If we require an extra load to get this address, as in PIC mode, we
    // can't accept it.
    if (isGlobalStubReference(Subtarget->ClassifyGlobalReference(GV,
                                                        getTargetMachine())))
      return;

    if (hasMemory)
      Op = LowerGlobalAddress(GV, Op.getDebugLoc(), Offset, DAG);
    else
      Op = DAG.getTargetGlobalAddress(GV, GA->getValueType(0), Offset);
    Result = Op;
    break;
  }
  }

  if (Result.getNode()) {
    Ops.push_back(Result);
    return;
  }
  return TargetLowering::LowerAsmOperandForConstraint(Op, Constraint, hasMemory,
                                                      Ops, DAG);
}

std::vector<unsigned> X86TargetLowering::
getRegClassForInlineAsmConstraint(const std::string &Constraint,
                                  MVT VT) const {
  if (Constraint.size() == 1) {
    // FIXME: not handling fp-stack yet!
    switch (Constraint[0]) {      // GCC X86 Constraint Letters
    default: break;  // Unknown constraint letter
    case 'q':   // GENERAL_REGS in 64-bit mode, Q_REGS in 32-bit mode.
      if (Subtarget->is64Bit()) {
        if (VT == MVT::i32)
          return make_vector<unsigned>(X86::EAX, X86::EDX, X86::ECX, X86::EBX,
                                       X86::ESI, X86::EDI, X86::R8D, X86::R9D,
                                       X86::R10D,X86::R11D,X86::R12D,
                                       X86::R13D,X86::R14D,X86::R15D,
                                       X86::EBP, X86::ESP, 0);
        else if (VT == MVT::i16)
          return make_vector<unsigned>(X86::AX,  X86::DX,  X86::CX, X86::BX,
                                       X86::SI,  X86::DI,  X86::R8W,X86::R9W,
                                       X86::R10W,X86::R11W,X86::R12W,
                                       X86::R13W,X86::R14W,X86::R15W,
                                       X86::BP,  X86::SP, 0);
        else if (VT == MVT::i8)
          return make_vector<unsigned>(X86::AL,  X86::DL,  X86::CL, X86::BL,
                                       X86::SIL, X86::DIL, X86::R8B,X86::R9B,
                                       X86::R10B,X86::R11B,X86::R12B,
                                       X86::R13B,X86::R14B,X86::R15B,
                                       X86::BPL, X86::SPL, 0);

        else if (VT == MVT::i64)
          return make_vector<unsigned>(X86::RAX, X86::RDX, X86::RCX, X86::RBX,
                                       X86::RSI, X86::RDI, X86::R8,  X86::R9,
                                       X86::R10, X86::R11, X86::R12,
                                       X86::R13, X86::R14, X86::R15,
                                       X86::RBP, X86::RSP, 0);

        break;
      }
      // 32-bit fallthrough 
    case 'Q':   // Q_REGS
      if (VT == MVT::i32)
        return make_vector<unsigned>(X86::EAX, X86::EDX, X86::ECX, X86::EBX, 0);
      else if (VT == MVT::i16)
        return make_vector<unsigned>(X86::AX, X86::DX, X86::CX, X86::BX, 0);
      else if (VT == MVT::i8)
        return make_vector<unsigned>(X86::AL, X86::DL, X86::CL, X86::BL, 0);
      else if (VT == MVT::i64)
        return make_vector<unsigned>(X86::RAX, X86::RDX, X86::RCX, X86::RBX, 0);
      break;
    }
  }

  return std::vector<unsigned>();
}

std::pair<unsigned, const TargetRegisterClass*>
X86TargetLowering::getRegForInlineAsmConstraint(const std::string &Constraint,
                                                MVT VT) const {
  // First, see if this is a constraint that directly corresponds to an LLVM
  // register class.
  if (Constraint.size() == 1) {
    // GCC Constraint Letters
    switch (Constraint[0]) {
    default: break;
    case 'r':   // GENERAL_REGS
    case 'R':   // LEGACY_REGS
    case 'l':   // INDEX_REGS
      if (VT == MVT::i8)
        return std::make_pair(0U, X86::GR8RegisterClass);
      if (VT == MVT::i16)
        return std::make_pair(0U, X86::GR16RegisterClass);
      if (VT == MVT::i32 || !Subtarget->is64Bit())
        return std::make_pair(0U, X86::GR32RegisterClass);
      return std::make_pair(0U, X86::GR64RegisterClass);
    case 'f':  // FP Stack registers.
      // If SSE is enabled for this VT, use f80 to ensure the isel moves the
      // value to the correct fpstack register class.
      if (VT == MVT::f32 && !isScalarFPTypeInSSEReg(VT))
        return std::make_pair(0U, X86::RFP32RegisterClass);
      if (VT == MVT::f64 && !isScalarFPTypeInSSEReg(VT))
        return std::make_pair(0U, X86::RFP64RegisterClass);
      return std::make_pair(0U, X86::RFP80RegisterClass);
    case 'y':   // MMX_REGS if MMX allowed.
      if (!Subtarget->hasMMX()) break;
      return std::make_pair(0U, X86::VR64RegisterClass);
    case 'Y':   // SSE_REGS if SSE2 allowed
      if (!Subtarget->hasSSE2()) break;
      // FALL THROUGH.
    case 'x':   // SSE_REGS if SSE1 allowed
      if (!Subtarget->hasSSE1()) break;

      switch (VT.getSimpleVT()) {
      default: break;
      // Scalar SSE types.
      case MVT::f32:
      case MVT::i32:
        return std::make_pair(0U, X86::FR32RegisterClass);
      case MVT::f64:
      case MVT::i64:
        return std::make_pair(0U, X86::FR64RegisterClass);
      // Vector types.
      case MVT::v16i8:
      case MVT::v8i16:
      case MVT::v4i32:
      case MVT::v2i64:
      case MVT::v4f32:
      case MVT::v2f64:
        return std::make_pair(0U, X86::VR128RegisterClass);
      }
      break;
    }
  }

  // Use the default implementation in TargetLowering to convert the register
  // constraint into a member of a register class.
  std::pair<unsigned, const TargetRegisterClass*> Res;
  Res = TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);

  // Not found as a standard register?
  if (Res.second == 0) {
    // GCC calls "st(0)" just plain "st".
    if (StringsEqualNoCase("{st}", Constraint)) {
      Res.first = X86::ST0;
      Res.second = X86::RFP80RegisterClass;
    }
    // 'A' means EAX + EDX.
    if (Constraint == "A") {
      Res.first = X86::EAX;
      Res.second = X86::GR32_ADRegisterClass;
    }
    return Res;
  }

  // Otherwise, check to see if this is a register class of the wrong value
  // type.  For example, we want to map "{ax},i32" -> {eax}, we don't want it to
  // turn into {ax},{dx}.
  if (Res.second->hasType(VT))
    return Res;   // Correct type already, nothing to do.

  // All of the single-register GCC register classes map their values onto
  // 16-bit register pieces "ax","dx","cx","bx","si","di","bp","sp".  If we
  // really want an 8-bit or 32-bit register, map to the appropriate register
  // class and return the appropriate register.
  if (Res.second == X86::GR16RegisterClass) {
    if (VT == MVT::i8) {
      unsigned DestReg = 0;
      switch (Res.first) {
      default: break;
      case X86::AX: DestReg = X86::AL; break;
      case X86::DX: DestReg = X86::DL; break;
      case X86::CX: DestReg = X86::CL; break;
      case X86::BX: DestReg = X86::BL; break;
      }
      if (DestReg) {
        Res.first = DestReg;
        Res.second = X86::GR8RegisterClass;
      }
    } else if (VT == MVT::i32) {
      unsigned DestReg = 0;
      switch (Res.first) {
      default: break;
      case X86::AX: DestReg = X86::EAX; break;
      case X86::DX: DestReg = X86::EDX; break;
      case X86::CX: DestReg = X86::ECX; break;
      case X86::BX: DestReg = X86::EBX; break;
      case X86::SI: DestReg = X86::ESI; break;
      case X86::DI: DestReg = X86::EDI; break;
      case X86::BP: DestReg = X86::EBP; break;
      case X86::SP: DestReg = X86::ESP; break;
      }
      if (DestReg) {
        Res.first = DestReg;
        Res.second = X86::GR32RegisterClass;
      }
    } else if (VT == MVT::i64) {
      unsigned DestReg = 0;
      switch (Res.first) {
      default: break;
      case X86::AX: DestReg = X86::RAX; break;
      case X86::DX: DestReg = X86::RDX; break;
      case X86::CX: DestReg = X86::RCX; break;
      case X86::BX: DestReg = X86::RBX; break;
      case X86::SI: DestReg = X86::RSI; break;
      case X86::DI: DestReg = X86::RDI; break;
      case X86::BP: DestReg = X86::RBP; break;
      case X86::SP: DestReg = X86::RSP; break;
      }
      if (DestReg) {
        Res.first = DestReg;
        Res.second = X86::GR64RegisterClass;
      }
    }
  } else if (Res.second == X86::FR32RegisterClass ||
             Res.second == X86::FR64RegisterClass ||
             Res.second == X86::VR128RegisterClass) {
    // Handle references to XMM physical registers that got mapped into the
    // wrong class.  This can happen with constraints like {xmm0} where the
    // target independent register mapper will just pick the first match it can
    // find, ignoring the required type.
    if (VT == MVT::f32)
      Res.second = X86::FR32RegisterClass;
    else if (VT == MVT::f64)
      Res.second = X86::FR64RegisterClass;
    else if (X86::VR128RegisterClass->hasType(VT))
      Res.second = X86::VR128RegisterClass;
  }

  return Res;
}

//===----------------------------------------------------------------------===//
//                           X86 Widen vector type
//===----------------------------------------------------------------------===//

/// getWidenVectorType: given a vector type, returns the type to widen
/// to (e.g., v7i8 to v8i8). If the vector type is legal, it returns itself.
/// If there is no vector type that we want to widen to, returns MVT::Other
/// When and where to widen is target dependent based on the cost of
/// scalarizing vs using the wider vector type.

MVT X86TargetLowering::getWidenVectorType(MVT VT) const {
  assert(VT.isVector());
  if (isTypeLegal(VT))
    return VT;

  // TODO: In computeRegisterProperty, we can compute the list of legal vector
  //       type based on element type.  This would speed up our search (though
  //       it may not be worth it since the size of the list is relatively
  //       small).
  MVT EltVT = VT.getVectorElementType();
  unsigned NElts = VT.getVectorNumElements();

  // On X86, it make sense to widen any vector wider than 1
  if (NElts <= 1)
    return MVT::Other;

  for (unsigned nVT = MVT::FIRST_VECTOR_VALUETYPE;
       nVT <= MVT::LAST_VECTOR_VALUETYPE; ++nVT) {
    MVT SVT = (MVT::SimpleValueType)nVT;

    if (isTypeLegal(SVT) &&
        SVT.getVectorElementType() == EltVT &&
        SVT.getVectorNumElements() > NElts)
      return SVT;
  }
  return MVT::Other;
}