lib/Target/Mips/MipsISelDAGToDAG.cpp - fp2-dev/platform/external/llvm - Gitiles

 //===-- MipsISelDAGToDAG.cpp - A dag to dag inst selector for Mips --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines an instruction selector for the MIPS target.
 //
 //===----------------------------------------------------------------------===//

 #define DEBUG_TYPE "mips-isel"
 #include "Mips.h"
 #include "MipsMachineFunction.h"
 #include "MipsRegisterInfo.h"
 #include "MipsSubtarget.h"
 #include "MipsTargetMachine.h"
 #include "llvm/GlobalValue.h"
 #include "llvm/Instructions.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Type.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;

 //===----------------------------------------------------------------------===//
 // Instruction Selector Implementation
 //===----------------------------------------------------------------------===//

 //===----------------------------------------------------------------------===//
 // MipsDAGToDAGISel - MIPS specific code to select MIPS machine
 // instructions for SelectionDAG operations.
 //===----------------------------------------------------------------------===//
 namespace {

 class MipsDAGToDAGISel : public SelectionDAGISel {

   /// TM - Keep a reference to MipsTargetMachine.
   MipsTargetMachine &TM;

   /// Subtarget - Keep a pointer to the MipsSubtarget around so that we can
   /// make the right decision when generating code for different targets.
   const MipsSubtarget &Subtarget;

 public:
   explicit MipsDAGToDAGISel(MipsTargetMachine &tm) :
   SelectionDAGISel(tm),
   TM(tm), Subtarget(tm.getSubtarget<MipsSubtarget>()) {}

   // Pass Name
   virtual const char *getPassName() const {
     return "MIPS DAG->DAG Pattern Instruction Selection";
   }


 private:
   // Include the pieces autogenerated from the target description.
   #include "MipsGenDAGISel.inc"

   /// getTargetMachine - Return a reference to the TargetMachine, casted
   /// to the target-specific type.
   const MipsTargetMachine &getTargetMachine() {
     return static_cast<const MipsTargetMachine &>(TM);
   }

   /// getInstrInfo - Return a reference to the TargetInstrInfo, casted
   /// to the target-specific type.
   const MipsInstrInfo *getInstrInfo() {
     return getTargetMachine().getInstrInfo();
   }

   SDNode *getGlobalBaseReg();
   SDNode *Select(SDNode *N);

   // Complex Pattern.
   bool SelectAddr(SDValue N, SDValue &Base, SDValue &Offset);

   // getI32Imm - Return a target constant with the specified
   // value, of type i32.
   inline SDValue getI32Imm(unsigned Imm) {
     return CurDAG->getTargetConstant(Imm, MVT::i32);
   }

   virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
                                             char ConstraintCode,
                                             std::vector<SDValue> &OutOps);
 };

 }


 /// getGlobalBaseReg - Output the instructions required to put the
 /// GOT address into a register.
 SDNode *MipsDAGToDAGISel::getGlobalBaseReg() {
   unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
   return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
 }

 /// ComplexPattern used on MipsInstrInfo
 /// Used on Mips Load/Store instructions
 bool MipsDAGToDAGISel::
 SelectAddr(SDValue Addr, SDValue &Base, SDValue &Offset) {
   // if Address is FI, get the TargetFrameIndex.
   if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
     Base   = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
     Offset = CurDAG->getTargetConstant(0, MVT::i32);
     return true;
   }

   // on PIC code Load GA
   if (TM.getRelocationModel() == Reloc::PIC_) {
     if (Addr.getOpcode() == MipsISD::WrapperPIC) {
       Base   = CurDAG->getRegister(Mips::GP, MVT::i32);
       Offset = Addr.getOperand(0);
       return true;
     }
   } else {
     if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
         Addr.getOpcode() == ISD::TargetGlobalAddress))
       return false;
     else if (Addr.getOpcode() == ISD::TargetGlobalTLSAddress) {
       Base   = CurDAG->getRegister(Mips::GP, MVT::i32);
       Offset = Addr;
       return true;
     }
   }

   // Addresses of the form FI+const or FI|const
   if (CurDAG->isBaseWithConstantOffset(Addr)) {
     ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
     if (isInt<16>(CN->getSExtValue())) {

       // If the first operand is a FI, get the TargetFI Node
       if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
                                   (Addr.getOperand(0)))
         Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
       else
         Base = Addr.getOperand(0);

       Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
       return true;
     }
   }

   // Operand is a result from an ADD.
   if (Addr.getOpcode() == ISD::ADD) {
     // When loading from constant pools, load the lower address part in
     // the instruction itself. Example, instead of:
     //  lui $2, %hi($CPI1_0)
     //  addiu $2, $2, %lo($CPI1_0)
     //  lwc1 $f0, 0($2)
     // Generate:
     //  lui $2, %hi($CPI1_0)
     //  lwc1 $f0, %lo($CPI1_0)($2)
     if ((Addr.getOperand(0).getOpcode() == MipsISD::Hi ||
          Addr.getOperand(0).getOpcode() == ISD::LOAD) &&
         Addr.getOperand(1).getOpcode() == MipsISD::Lo) {
       SDValue LoVal = Addr.getOperand(1);
       if (isa<ConstantPoolSDNode>(LoVal.getOperand(0)) ||
           isa<GlobalAddressSDNode>(LoVal.getOperand(0))) {
         Base = Addr.getOperand(0);
         Offset = LoVal.getOperand(0);
         return true;
       }
     }
   }

   Base   = Addr;
   Offset = CurDAG->getTargetConstant(0, MVT::i32);
   return true;
 }

 /// Select instructions not customized! Used for
 /// expanded, promoted and normal instructions
 SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
   unsigned Opcode = Node->getOpcode();
   DebugLoc dl = Node->getDebugLoc();

   // Dump information about the Node being selected
   DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");

   // If we have a custom node, we already have selected!
   if (Node->isMachineOpcode()) {
     DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
     return NULL;
   }

   ///
   // Instruction Selection not handled by the auto-generated
   // tablegen selection should be handled here.
   ///
   switch(Opcode) {
     default: break;

     case ISD::SUBE:
     case ISD::ADDE: {
       SDValue InFlag = Node->getOperand(2), CmpLHS;
       unsigned Opc = InFlag.getOpcode(); (void)Opc;
       assert(((Opc == ISD::ADDC || Opc == ISD::ADDE) ||
               (Opc == ISD::SUBC || Opc == ISD::SUBE)) &&
              "(ADD|SUB)E flag operand must come from (ADD|SUB)C/E insn");

       unsigned MOp;
       if (Opcode == ISD::ADDE) {
         CmpLHS = InFlag.getValue(0);
         MOp = Mips::ADDu;
       } else {
         CmpLHS = InFlag.getOperand(0);
         MOp = Mips::SUBu;
       }

       SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };

       SDValue LHS = Node->getOperand(0);
       SDValue RHS = Node->getOperand(1);

       EVT VT = LHS.getValueType();
       SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, dl, VT, Ops, 2);
       SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, dl, VT,
                                                 SDValue(Carry,0), RHS);

       return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue,
                                   LHS, SDValue(AddCarry,0));
     }

     /// Mul with two results
     case ISD::SMUL_LOHI:
     case ISD::UMUL_LOHI: {
       SDValue Op1 = Node->getOperand(0);
       SDValue Op2 = Node->getOperand(1);

       unsigned Op;
       Op = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);

       SDNode *Mul = CurDAG->getMachineNode(Op, dl, MVT::Glue, Op1, Op2);

       SDValue InFlag = SDValue(Mul, 0);
       SDNode *Lo = CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32,
                                           MVT::Glue, InFlag);
       InFlag = SDValue(Lo,1);
       SDNode *Hi = CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);

       if (!SDValue(Node, 0).use_empty())
         ReplaceUses(SDValue(Node, 0), SDValue(Lo,0));

       if (!SDValue(Node, 1).use_empty())
         ReplaceUses(SDValue(Node, 1), SDValue(Hi,0));

       return NULL;
     }

     /// Special Muls
     case ISD::MUL:
       if (Subtarget.isMips32())
         break;
     case ISD::MULHS:
     case ISD::MULHU: {
       SDValue MulOp1 = Node->getOperand(0);
       SDValue MulOp2 = Node->getOperand(1);

       unsigned MulOp  = (Opcode == ISD::MULHU ? Mips::MULTu : Mips::MULT);
       SDNode *MulNode = CurDAG->getMachineNode(MulOp, dl,
                                                MVT::Glue, MulOp1, MulOp2);

       SDValue InFlag = SDValue(MulNode, 0);

       if (Opcode == ISD::MUL)
         return CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32, InFlag);
       else
         return CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
     }

     // Get target GOT address.
     case ISD::GLOBAL_OFFSET_TABLE:
       return getGlobalBaseReg();

     case ISD::ConstantFP: {
       ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
       if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
         SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
                                         Mips::ZERO, MVT::i32);
         return CurDAG->getMachineNode(Mips::BuildPairF64, dl, MVT::f64, Zero,
                                       Zero);
       }
       break;
     }

     case MipsISD::ThreadPointer: {
       unsigned SrcReg = Mips::HWR29;
       unsigned DestReg = Mips::V1;
       SDNode *Rdhwr = CurDAG->getMachineNode(Mips::RDHWR, Node->getDebugLoc(),
           Node->getValueType(0), CurDAG->getRegister(SrcReg, MVT::i32));
       SDValue Chain = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, DestReg,
           SDValue(Rdhwr, 0));
       SDValue ResNode = CurDAG->getCopyFromReg(Chain, dl, DestReg, MVT::i32);
       ReplaceUses(SDValue(Node, 0), ResNode);
       return ResNode.getNode();
     }
   }

   // Select the default instruction
   SDNode *ResNode = SelectCode(Node);

   DEBUG(errs() << "=> ");
   if (ResNode == NULL || ResNode == Node)
     DEBUG(Node->dump(CurDAG));
   else
     DEBUG(ResNode->dump(CurDAG));
   DEBUG(errs() << "\n");
   return ResNode;
 }

 bool MipsDAGToDAGISel::
 SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
                              std::vector<SDValue> &OutOps) {
   assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
   OutOps.push_back(Op);
   return false;
 }

 /// createMipsISelDag - This pass converts a legalized DAG into a
 /// MIPS-specific DAG, ready for instruction scheduling.
 FunctionPass *llvm::createMipsISelDag(MipsTargetMachine &TM) {
   return new MipsDAGToDAGISel(TM);
 }
	//===-- MipsISelDAGToDAG.cpp - A dag to dag inst selector for Mips --------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file defines an instruction selector for the MIPS target.
	//
	//===----------------------------------------------------------------------===//

	#define DEBUG_TYPE "mips-isel"
	#include "Mips.h"
	#include "MipsMachineFunction.h"
	#include "MipsRegisterInfo.h"
	#include "MipsSubtarget.h"
	#include "MipsTargetMachine.h"
	#include "llvm/GlobalValue.h"
	#include "llvm/Instructions.h"
	#include "llvm/Intrinsics.h"
	#include "llvm/Support/CFG.h"
	#include "llvm/Type.h"
	#include "llvm/CodeGen/MachineConstantPool.h"
	#include "llvm/CodeGen/MachineFunction.h"
	#include "llvm/CodeGen/MachineFrameInfo.h"
	#include "llvm/CodeGen/MachineInstrBuilder.h"
	#include "llvm/CodeGen/MachineRegisterInfo.h"
	#include "llvm/CodeGen/SelectionDAGISel.h"
	#include "llvm/Target/TargetMachine.h"
	#include "llvm/Support/Debug.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"
	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// Instruction Selector Implementation
	//===----------------------------------------------------------------------===//

	//===----------------------------------------------------------------------===//
	// MipsDAGToDAGISel - MIPS specific code to select MIPS machine
	// instructions for SelectionDAG operations.
	//===----------------------------------------------------------------------===//
	namespace {

	class MipsDAGToDAGISel : public SelectionDAGISel {

	/// TM - Keep a reference to MipsTargetMachine.
	MipsTargetMachine &TM;

	/// Subtarget - Keep a pointer to the MipsSubtarget around so that we can
	/// make the right decision when generating code for different targets.
	const MipsSubtarget &Subtarget;

	public:
	explicit MipsDAGToDAGISel(MipsTargetMachine &tm) :
	SelectionDAGISel(tm),
	TM(tm), Subtarget(tm.getSubtarget<MipsSubtarget>()) {}

	// Pass Name
	virtual const char *getPassName() const {
	return "MIPS DAG->DAG Pattern Instruction Selection";
	}


	private:
	// Include the pieces autogenerated from the target description.
	#include "MipsGenDAGISel.inc"

	/// getTargetMachine - Return a reference to the TargetMachine, casted
	/// to the target-specific type.
	const MipsTargetMachine &getTargetMachine() {
	return static_cast<const MipsTargetMachine &>(TM);
	}

	/// getInstrInfo - Return a reference to the TargetInstrInfo, casted
	/// to the target-specific type.
	const MipsInstrInfo *getInstrInfo() {
	return getTargetMachine().getInstrInfo();
	}

	SDNode *getGlobalBaseReg();
	SDNode Select(SDNode N);

	// Complex Pattern.
	bool SelectAddr(SDValue N, SDValue &Base, SDValue &Offset);

	// getI32Imm - Return a target constant with the specified
	// value, of type i32.
	inline SDValue getI32Imm(unsigned Imm) {
	return CurDAG->getTargetConstant(Imm, MVT::i32);
	}

	virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
	char ConstraintCode,
	std::vector<SDValue> &OutOps);
	};

	}


	/// getGlobalBaseReg - Output the instructions required to put the
	/// GOT address into a register.
	SDNode *MipsDAGToDAGISel::getGlobalBaseReg() {
	unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
	return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
	}

	/// ComplexPattern used on MipsInstrInfo
	/// Used on Mips Load/Store instructions
	bool MipsDAGToDAGISel::
	SelectAddr(SDValue Addr, SDValue &Base, SDValue &Offset) {
	// if Address is FI, get the TargetFrameIndex.
	if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
	Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
	Offset = CurDAG->getTargetConstant(0, MVT::i32);
	return true;
	}

	// on PIC code Load GA
	if (TM.getRelocationModel() == Reloc::PIC_) {
	if (Addr.getOpcode() == MipsISD::WrapperPIC) {
	Base = CurDAG->getRegister(Mips::GP, MVT::i32);
	Offset = Addr.getOperand(0);
	return true;
	}
	} else {
	if ((Addr.getOpcode() == ISD::TargetExternalSymbol \|\|
	Addr.getOpcode() == ISD::TargetGlobalAddress))
	return false;
	else if (Addr.getOpcode() == ISD::TargetGlobalTLSAddress) {
	Base = CurDAG->getRegister(Mips::GP, MVT::i32);
	Offset = Addr;
	return true;
	}
	}

	// Addresses of the form FI+const or FI\|const
	if (CurDAG->isBaseWithConstantOffset(Addr)) {
	ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
	if (isInt<16>(CN->getSExtValue())) {

	// If the first operand is a FI, get the TargetFI Node
	if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
	(Addr.getOperand(0)))
	Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
	else
	Base = Addr.getOperand(0);

	Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
	return true;
	}
	}

	// Operand is a result from an ADD.
	if (Addr.getOpcode() == ISD::ADD) {
	// When loading from constant pools, load the lower address part in
	// the instruction itself. Example, instead of:
	// lui $2, %hi($CPI1_0)
	// addiu $2, $2, %lo($CPI1_0)
	// lwc1 $f0, 0($2)
	// Generate:
	// lui $2, %hi($CPI1_0)
	// lwc1 $f0, %lo($CPI1_0)($2)
	if ((Addr.getOperand(0).getOpcode() == MipsISD::Hi \|\|
	Addr.getOperand(0).getOpcode() == ISD::LOAD) &&
	Addr.getOperand(1).getOpcode() == MipsISD::Lo) {
	SDValue LoVal = Addr.getOperand(1);
	if (isa<ConstantPoolSDNode>(LoVal.getOperand(0)) \|\|
	isa<GlobalAddressSDNode>(LoVal.getOperand(0))) {
	Base = Addr.getOperand(0);
	Offset = LoVal.getOperand(0);
	return true;
	}
	}
	}

	Base = Addr;
	Offset = CurDAG->getTargetConstant(0, MVT::i32);
	return true;
	}

	/// Select instructions not customized! Used for
	/// expanded, promoted and normal instructions
	SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
	unsigned Opcode = Node->getOpcode();
	DebugLoc dl = Node->getDebugLoc();

	// Dump information about the Node being selected
	DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");

	// If we have a custom node, we already have selected!
	if (Node->isMachineOpcode()) {
	DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
	return NULL;
	}

	///
	// Instruction Selection not handled by the auto-generated
	// tablegen selection should be handled here.
	///
	switch(Opcode) {
	default: break;

	case ISD::SUBE:
	case ISD::ADDE: {
	SDValue InFlag = Node->getOperand(2), CmpLHS;
	unsigned Opc = InFlag.getOpcode(); (void)Opc;
	assert(((Opc == ISD::ADDC \|\| Opc == ISD::ADDE) \|\|
	(Opc == ISD::SUBC \|\| Opc == ISD::SUBE)) &&
	"(ADD\|SUB)E flag operand must come from (ADD\|SUB)C/E insn");

	unsigned MOp;
	if (Opcode == ISD::ADDE) {
	CmpLHS = InFlag.getValue(0);
	MOp = Mips::ADDu;
	} else {
	CmpLHS = InFlag.getOperand(0);
	MOp = Mips::SUBu;
	}

	SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };

	SDValue LHS = Node->getOperand(0);
	SDValue RHS = Node->getOperand(1);

	EVT VT = LHS.getValueType();
	SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, dl, VT, Ops, 2);
	SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, dl, VT,
	SDValue(Carry,0), RHS);

	return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue,
	LHS, SDValue(AddCarry,0));
	}

	/// Mul with two results
	case ISD::SMUL_LOHI:
	case ISD::UMUL_LOHI: {
	SDValue Op1 = Node->getOperand(0);
	SDValue Op2 = Node->getOperand(1);

	unsigned Op;
	Op = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);

	SDNode *Mul = CurDAG->getMachineNode(Op, dl, MVT::Glue, Op1, Op2);

	SDValue InFlag = SDValue(Mul, 0);
	SDNode *Lo = CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32,
	MVT::Glue, InFlag);
	InFlag = SDValue(Lo,1);
	SDNode *Hi = CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);

	if (!SDValue(Node, 0).use_empty())
	ReplaceUses(SDValue(Node, 0), SDValue(Lo,0));

	if (!SDValue(Node, 1).use_empty())
	ReplaceUses(SDValue(Node, 1), SDValue(Hi,0));

	return NULL;
	}

	/// Special Muls
	case ISD::MUL:
	if (Subtarget.isMips32())
	break;
	case ISD::MULHS:
	case ISD::MULHU: {
	SDValue MulOp1 = Node->getOperand(0);
	SDValue MulOp2 = Node->getOperand(1);

	unsigned MulOp = (Opcode == ISD::MULHU ? Mips::MULTu : Mips::MULT);
	SDNode *MulNode = CurDAG->getMachineNode(MulOp, dl,
	MVT::Glue, MulOp1, MulOp2);

	SDValue InFlag = SDValue(MulNode, 0);

	if (Opcode == ISD::MUL)
	return CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32, InFlag);
	else
	return CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
	}

	// Get target GOT address.
	case ISD::GLOBAL_OFFSET_TABLE:
	return getGlobalBaseReg();

	case ISD::ConstantFP: {
	ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
	if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
	SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
	Mips::ZERO, MVT::i32);
	return CurDAG->getMachineNode(Mips::BuildPairF64, dl, MVT::f64, Zero,
	Zero);
	}
	break;
	}

	case MipsISD::ThreadPointer: {
	unsigned SrcReg = Mips::HWR29;
	unsigned DestReg = Mips::V1;
	SDNode *Rdhwr = CurDAG->getMachineNode(Mips::RDHWR, Node->getDebugLoc(),
	Node->getValueType(0), CurDAG->getRegister(SrcReg, MVT::i32));
	SDValue Chain = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, DestReg,
	SDValue(Rdhwr, 0));
	SDValue ResNode = CurDAG->getCopyFromReg(Chain, dl, DestReg, MVT::i32);
	ReplaceUses(SDValue(Node, 0), ResNode);
	return ResNode.getNode();
	}
	}

	// Select the default instruction
	SDNode *ResNode = SelectCode(Node);

	DEBUG(errs() << "=> ");
	if (ResNode == NULL \|\| ResNode == Node)
	DEBUG(Node->dump(CurDAG));
	else
	DEBUG(ResNode->dump(CurDAG));
	DEBUG(errs() << "\n");
	return ResNode;
	}

	bool MipsDAGToDAGISel::
	SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
	std::vector<SDValue> &OutOps) {
	assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
	OutOps.push_back(Op);
	return false;
	}

	/// createMipsISelDag - This pass converts a legalized DAG into a
	/// MIPS-specific DAG, ready for instruction scheduling.
	FunctionPass *llvm::createMipsISelDag(MipsTargetMachine &TM) {
	return new MipsDAGToDAGISel(TM);
	}