lib/Target/X86/X86SelectionDAGInfo.cpp - llvm - Git at Google

 //===-- X86SelectionDAGInfo.cpp - X86 SelectionDAG Info -------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the X86SelectionDAGInfo class.
 //
 //===----------------------------------------------------------------------===//

 #include "X86SelectionDAGInfo.h"
 #include "X86ISelLowering.h"
 #include "X86InstrInfo.h"
 #include "X86RegisterInfo.h"
 #include "X86Subtarget.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/IR/DerivedTypes.h"

 using namespace llvm;

 #define DEBUG_TYPE "x86-selectiondag-info"

 bool X86SelectionDAGInfo::isBaseRegConflictPossible(
     SelectionDAG &DAG, ArrayRef<MCPhysReg> ClobberSet) const {
   // We cannot use TRI->hasBasePointer() until *after* we select all basic
   // blocks.  Legalization may introduce new stack temporaries with large
   // alignment requirements.  Fall back to generic code if there are any
   // dynamic stack adjustments (hopefully rare) and the base pointer would
   // conflict if we had to use it.
   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
   if (!MFI.hasVarSizedObjects() && !MFI.hasOpaqueSPAdjustment())
     return false;

   const X86RegisterInfo *TRI = static_cast<const X86RegisterInfo *>(
       DAG.getSubtarget().getRegisterInfo());
   unsigned BaseReg = TRI->getBaseRegister();
   for (unsigned R : ClobberSet)
     if (BaseReg == R)
       return true;
   return false;
 }

 namespace {

 // Represents a cover of a buffer of Size bytes with Count() blocks of type AVT
 // (of size UBytes() bytes), as well as how many bytes remain (BytesLeft() is
 // always smaller than the block size).
 struct RepMovsRepeats {
   RepMovsRepeats(uint64_t Size) : Size(Size) {}

   uint64_t Count() const { return Size / UBytes(); }
   uint64_t BytesLeft() const { return Size % UBytes(); }
   uint64_t UBytes() const { return AVT.getSizeInBits() / 8; }

   const uint64_t Size;
   MVT AVT = MVT::i8;
 };

 }  // namespace

 SDValue X86SelectionDAGInfo::EmitTargetCodeForMemset(
     SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Val,
     SDValue Size, unsigned Align, bool isVolatile,
     MachinePointerInfo DstPtrInfo) const {
   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
   const X86Subtarget &Subtarget =
       DAG.getMachineFunction().getSubtarget<X86Subtarget>();

 #ifndef NDEBUG
   // If the base register might conflict with our physical registers, bail out.
   const MCPhysReg ClobberSet[] = {X86::RCX, X86::RAX, X86::RDI,
                                   X86::ECX, X86::EAX, X86::EDI};
   assert(!isBaseRegConflictPossible(DAG, ClobberSet));
 #endif

   // If to a segment-relative address space, use the default lowering.
   if (DstPtrInfo.getAddrSpace() >= 256)
     return SDValue();

   // 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() > Subtarget.getMaxInlineSizeThreshold()) {
     // Check to see if there is a specialized entry-point for memory zeroing.
     ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);

     if (const char *bzeroName = (ValC && ValC->isNullValue())
         ? DAG.getTargetLoweringInfo().getLibcallName(RTLIB::BZERO)
         : nullptr) {
       const TargetLowering &TLI = DAG.getTargetLoweringInfo();
       EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
       Type *IntPtrTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
       TargetLowering::ArgListTy Args;
       TargetLowering::ArgListEntry Entry;
       Entry.Node = Dst;
       Entry.Ty = IntPtrTy;
       Args.push_back(Entry);
       Entry.Node = Size;
       Args.push_back(Entry);

       TargetLowering::CallLoweringInfo CLI(DAG);
       CLI.setDebugLoc(dl)
           .setChain(Chain)
           .setLibCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
                         DAG.getExternalSymbol(bzeroName, IntPtr),
                         std::move(Args))
           .setDiscardResult();

       std::pair<SDValue,SDValue> CallResult = TLI.LowerCallTo(CLI);
       return CallResult.second;
     }

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

   uint64_t SizeVal = ConstantSize->getZExtValue();
   SDValue InFlag;
   EVT AVT;
   SDValue Count;
   ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);
   unsigned BytesLeft = 0;
   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, dl);
       break;
     }

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

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

   bool Use64BitRegs = Subtarget.isTarget64BitLP64();
   Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RCX : X86::ECX,
                            Count, InFlag);
   InFlag = Chain.getValue(1);
   Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RDI : X86::EDI,
                            Dst, InFlag);
   InFlag = Chain.getValue(1);

   SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
   SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
   Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops);

   if (BytesLeft) {
     // Handle the last 1 - 7 bytes.
     unsigned Offset = SizeVal - BytesLeft;
     EVT AddrVT = Dst.getValueType();
     EVT SizeVT = Size.getValueType();

     Chain = DAG.getMemset(Chain, dl,
                           DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
                                       DAG.getConstant(Offset, dl, AddrVT)),
                           Val,
                           DAG.getConstant(BytesLeft, dl, SizeVT),
                           Align, isVolatile, false,
                           DstPtrInfo.getWithOffset(Offset));
   }

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

 SDValue X86SelectionDAGInfo::EmitTargetCodeForMemcpy(
     SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
     SDValue Size, unsigned Align, bool isVolatile, bool AlwaysInline,
     MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
   // This requires the copy size to be a constant, preferably
   // within a subtarget-specific limit.
   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
   const X86Subtarget &Subtarget =
       DAG.getMachineFunction().getSubtarget<X86Subtarget>();
   if (!ConstantSize)
     return SDValue();
   RepMovsRepeats Repeats(ConstantSize->getZExtValue());
   if (!AlwaysInline && Repeats.Size > Subtarget.getMaxInlineSizeThreshold())
     return SDValue();

   /// If not DWORD aligned, it is more efficient to call the library.  However
   /// if calling the library is not allowed (AlwaysInline), then soldier on as
   /// the code generated here is better than the long load-store sequence we
   /// would otherwise get.
   if (!AlwaysInline && (Align & 3) != 0)
     return SDValue();

   // If to a segment-relative address space, use the default lowering.
   if (DstPtrInfo.getAddrSpace() >= 256 ||
       SrcPtrInfo.getAddrSpace() >= 256)
     return SDValue();

   // If the base register might conflict with our physical registers, bail out.
   const MCPhysReg ClobberSet[] = {X86::RCX, X86::RSI, X86::RDI,
                                   X86::ECX, X86::ESI, X86::EDI};
   if (isBaseRegConflictPossible(DAG, ClobberSet))
     return SDValue();

   // If the target has enhanced REPMOVSB, then it's at least as fast to use
   // REP MOVSB instead of REP MOVS{W,D,Q}, and it avoids having to handle
   // BytesLeft.
   if (!Subtarget.hasERMSB() && !(Align & 1)) {
     if (Align & 2)
       // WORD aligned
       Repeats.AVT = MVT::i16;
     else if (Align & 4)
       // DWORD aligned
       Repeats.AVT = MVT::i32;
     else
       // QWORD aligned
       Repeats.AVT = Subtarget.is64Bit() ? MVT::i64 : MVT::i32;

     if (Repeats.BytesLeft() > 0 &&
         DAG.getMachineFunction().getFunction().optForMinSize()) {
       // When aggressively optimizing for size, avoid generating the code to
       // handle BytesLeft.
       Repeats.AVT = MVT::i8;
     }
   }

   bool Use64BitRegs = Subtarget.isTarget64BitLP64();
   SDValue InFlag;
   Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RCX : X86::ECX,
                            DAG.getIntPtrConstant(Repeats.Count(), dl), InFlag);
   InFlag = Chain.getValue(1);
   Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RDI : X86::EDI,
                            Dst, InFlag);
   InFlag = Chain.getValue(1);
   Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RSI : X86::ESI,
                            Src, InFlag);
   InFlag = Chain.getValue(1);

   SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
   SDValue Ops[] = { Chain, DAG.getValueType(Repeats.AVT), InFlag };
   SDValue RepMovs = DAG.getNode(X86ISD::REP_MOVS, dl, Tys, Ops);

   SmallVector<SDValue, 4> Results;
   Results.push_back(RepMovs);
   if (Repeats.BytesLeft()) {
     // Handle the last 1 - 7 bytes.
     unsigned Offset = Repeats.Size - Repeats.BytesLeft();
     EVT DstVT = Dst.getValueType();
     EVT SrcVT = Src.getValueType();
     EVT SizeVT = Size.getValueType();
     Results.push_back(DAG.getMemcpy(Chain, dl,
                                     DAG.getNode(ISD::ADD, dl, DstVT, Dst,
                                                 DAG.getConstant(Offset, dl,
                                                                 DstVT)),
                                     DAG.getNode(ISD::ADD, dl, SrcVT, Src,
                                                 DAG.getConstant(Offset, dl,
                                                                 SrcVT)),
                                     DAG.getConstant(Repeats.BytesLeft(), dl,
                                                     SizeVT),
                                     Align, isVolatile, AlwaysInline, false,
                                     DstPtrInfo.getWithOffset(Offset),
                                     SrcPtrInfo.getWithOffset(Offset)));
   }

   return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Results);
 }
	//===-- X86SelectionDAGInfo.cpp - X86 SelectionDAG Info -------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the X86SelectionDAGInfo class.
	//
	//===----------------------------------------------------------------------===//

	#include "X86SelectionDAGInfo.h"
	#include "X86ISelLowering.h"
	#include "X86InstrInfo.h"
	#include "X86RegisterInfo.h"
	#include "X86Subtarget.h"
	#include "llvm/CodeGen/SelectionDAG.h"
	#include "llvm/CodeGen/TargetLowering.h"
	#include "llvm/IR/DerivedTypes.h"

	using namespace llvm;

	#define DEBUG_TYPE "x86-selectiondag-info"

	bool X86SelectionDAGInfo::isBaseRegConflictPossible(
	SelectionDAG &DAG, ArrayRef<MCPhysReg> ClobberSet) const {
	// We cannot use TRI->hasBasePointer() until after we select all basic
	// blocks. Legalization may introduce new stack temporaries with large
	// alignment requirements. Fall back to generic code if there are any
	// dynamic stack adjustments (hopefully rare) and the base pointer would
	// conflict if we had to use it.
	MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
	if (!MFI.hasVarSizedObjects() && !MFI.hasOpaqueSPAdjustment())
	return false;

	const X86RegisterInfo TRI = static_cast<const X86RegisterInfo >(
	DAG.getSubtarget().getRegisterInfo());
	unsigned BaseReg = TRI->getBaseRegister();
	for (unsigned R : ClobberSet)
	if (BaseReg == R)
	return true;
	return false;
	}

	namespace {

	// Represents a cover of a buffer of Size bytes with Count() blocks of type AVT
	// (of size UBytes() bytes), as well as how many bytes remain (BytesLeft() is
	// always smaller than the block size).
	struct RepMovsRepeats {
	RepMovsRepeats(uint64_t Size) : Size(Size) {}

	uint64_t Count() const { return Size / UBytes(); }
	uint64_t BytesLeft() const { return Size % UBytes(); }
	uint64_t UBytes() const { return AVT.getSizeInBits() / 8; }

	const uint64_t Size;
	MVT AVT = MVT::i8;
	};

	} // namespace

	SDValue X86SelectionDAGInfo::EmitTargetCodeForMemset(
	SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Val,
	SDValue Size, unsigned Align, bool isVolatile,
	MachinePointerInfo DstPtrInfo) const {
	ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
	const X86Subtarget &Subtarget =
	DAG.getMachineFunction().getSubtarget<X86Subtarget>();

	#ifndef NDEBUG
	// If the base register might conflict with our physical registers, bail out.
	const MCPhysReg ClobberSet[] = {X86::RCX, X86::RAX, X86::RDI,
	X86::ECX, X86::EAX, X86::EDI};
	assert(!isBaseRegConflictPossible(DAG, ClobberSet));
	#endif

	// If to a segment-relative address space, use the default lowering.
	if (DstPtrInfo.getAddrSpace() >= 256)
	return SDValue();

	// 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() > Subtarget.getMaxInlineSizeThreshold()) {
	// Check to see if there is a specialized entry-point for memory zeroing.
	ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);

	if (const char *bzeroName = (ValC && ValC->isNullValue())
	? DAG.getTargetLoweringInfo().getLibcallName(RTLIB::BZERO)
	: nullptr) {
	const TargetLowering &TLI = DAG.getTargetLoweringInfo();
	EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
	Type IntPtrTy = DAG.getDataLayout().getIntPtrType(DAG.getContext());
	TargetLowering::ArgListTy Args;
	TargetLowering::ArgListEntry Entry;
	Entry.Node = Dst;
	Entry.Ty = IntPtrTy;
	Args.push_back(Entry);
	Entry.Node = Size;
	Args.push_back(Entry);

	TargetLowering::CallLoweringInfo CLI(DAG);
	CLI.setDebugLoc(dl)
	.setChain(Chain)
	.setLibCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
	DAG.getExternalSymbol(bzeroName, IntPtr),
	std::move(Args))
	.setDiscardResult();

	std::pair<SDValue,SDValue> CallResult = TLI.LowerCallTo(CLI);
	return CallResult.second;
	}

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

	uint64_t SizeVal = ConstantSize->getZExtValue();
	SDValue InFlag;
	EVT AVT;
	SDValue Count;
	ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);
	unsigned BytesLeft = 0;
	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, dl);
	break;
	}

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

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

	bool Use64BitRegs = Subtarget.isTarget64BitLP64();
	Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RCX : X86::ECX,
	Count, InFlag);
	InFlag = Chain.getValue(1);
	Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RDI : X86::EDI,
	Dst, InFlag);
	InFlag = Chain.getValue(1);

	SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
	SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
	Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops);

	if (BytesLeft) {
	// Handle the last 1 - 7 bytes.
	unsigned Offset = SizeVal - BytesLeft;
	EVT AddrVT = Dst.getValueType();
	EVT SizeVT = Size.getValueType();

	Chain = DAG.getMemset(Chain, dl,
	DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
	DAG.getConstant(Offset, dl, AddrVT)),
	Val,
	DAG.getConstant(BytesLeft, dl, SizeVT),
	Align, isVolatile, false,
	DstPtrInfo.getWithOffset(Offset));
	}

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

	SDValue X86SelectionDAGInfo::EmitTargetCodeForMemcpy(
	SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
	SDValue Size, unsigned Align, bool isVolatile, bool AlwaysInline,
	MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
	// This requires the copy size to be a constant, preferably
	// within a subtarget-specific limit.
	ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
	const X86Subtarget &Subtarget =
	DAG.getMachineFunction().getSubtarget<X86Subtarget>();
	if (!ConstantSize)
	return SDValue();
	RepMovsRepeats Repeats(ConstantSize->getZExtValue());
	if (!AlwaysInline && Repeats.Size > Subtarget.getMaxInlineSizeThreshold())
	return SDValue();

	/// If not DWORD aligned, it is more efficient to call the library. However
	/// if calling the library is not allowed (AlwaysInline), then soldier on as
	/// the code generated here is better than the long load-store sequence we
	/// would otherwise get.
	if (!AlwaysInline && (Align & 3) != 0)
	return SDValue();

	// If to a segment-relative address space, use the default lowering.
	if (DstPtrInfo.getAddrSpace() >= 256 \|\|
	SrcPtrInfo.getAddrSpace() >= 256)
	return SDValue();

	// If the base register might conflict with our physical registers, bail out.
	const MCPhysReg ClobberSet[] = {X86::RCX, X86::RSI, X86::RDI,
	X86::ECX, X86::ESI, X86::EDI};
	if (isBaseRegConflictPossible(DAG, ClobberSet))
	return SDValue();

	// If the target has enhanced REPMOVSB, then it's at least as fast to use
	// REP MOVSB instead of REP MOVS{W,D,Q}, and it avoids having to handle
	// BytesLeft.
	if (!Subtarget.hasERMSB() && !(Align & 1)) {
	if (Align & 2)
	// WORD aligned
	Repeats.AVT = MVT::i16;
	else if (Align & 4)
	// DWORD aligned
	Repeats.AVT = MVT::i32;
	else
	// QWORD aligned
	Repeats.AVT = Subtarget.is64Bit() ? MVT::i64 : MVT::i32;

	if (Repeats.BytesLeft() > 0 &&
	DAG.getMachineFunction().getFunction().optForMinSize()) {
	// When aggressively optimizing for size, avoid generating the code to
	// handle BytesLeft.
	Repeats.AVT = MVT::i8;
	}
	}

	bool Use64BitRegs = Subtarget.isTarget64BitLP64();
	SDValue InFlag;
	Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RCX : X86::ECX,
	DAG.getIntPtrConstant(Repeats.Count(), dl), InFlag);
	InFlag = Chain.getValue(1);
	Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RDI : X86::EDI,
	Dst, InFlag);
	InFlag = Chain.getValue(1);
	Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RSI : X86::ESI,
	Src, InFlag);
	InFlag = Chain.getValue(1);

	SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
	SDValue Ops[] = { Chain, DAG.getValueType(Repeats.AVT), InFlag };
	SDValue RepMovs = DAG.getNode(X86ISD::REP_MOVS, dl, Tys, Ops);

	SmallVector<SDValue, 4> Results;
	Results.push_back(RepMovs);
	if (Repeats.BytesLeft()) {
	// Handle the last 1 - 7 bytes.
	unsigned Offset = Repeats.Size - Repeats.BytesLeft();
	EVT DstVT = Dst.getValueType();
	EVT SrcVT = Src.getValueType();
	EVT SizeVT = Size.getValueType();
	Results.push_back(DAG.getMemcpy(Chain, dl,
	DAG.getNode(ISD::ADD, dl, DstVT, Dst,
	DAG.getConstant(Offset, dl,
	DstVT)),
	DAG.getNode(ISD::ADD, dl, SrcVT, Src,
	DAG.getConstant(Offset, dl,
	SrcVT)),
	DAG.getConstant(Repeats.BytesLeft(), dl,
	SizeVT),
	Align, isVolatile, AlwaysInline, false,
	DstPtrInfo.getWithOffset(Offset),
	SrcPtrInfo.getWithOffset(Offset)));
	}

	return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Results);
	}