lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp - llvm - Git at Google

 //===-------- LegalizeTypesGeneric.cpp - Generic type legalization --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements generic type expansion and splitting for LegalizeTypes.
 // The routines here perform legalization when the details of the type (such as
 // whether it is an integer or a float) do not matter.
 // Expansion is the act of changing a computation in an illegal type to be a
 // computation in two identical registers of a smaller type.
 // Splitting is the act of changing a computation in an illegal type to be a
 // computation in two not necessarily identical registers of a smaller type.
 //
 //===----------------------------------------------------------------------===//

 #include "LegalizeTypes.h"
 using namespace llvm;

 //===----------------------------------------------------------------------===//
 // Generic Result Expansion.
 //===----------------------------------------------------------------------===//

 // These routines assume that the Lo/Hi part is stored first in memory on
 // little/big-endian machines, followed by the Hi/Lo part.  This means that
 // they cannot be used as is on vectors, for which Lo is always stored first.

 void DAGTypeLegalizer::ExpandRes_BIT_CONVERT(SDNode *N, SDValue &Lo,
                                              SDValue &Hi) {
   MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));
   SDValue InOp = N->getOperand(0);
   MVT InVT = InOp.getValueType();

   // Handle some special cases efficiently.
   switch (getTypeAction(InVT)) {
     default:
       assert(false && "Unknown type action!");
     case Legal:
     case PromoteInteger:
       break;
     case SoftenFloat:
       // Convert the integer operand instead.
       SplitInteger(GetSoftenedFloat(InOp), Lo, Hi);
       Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
       Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
       return;
     case ExpandInteger:
     case ExpandFloat:
       // Convert the expanded pieces of the input.
       GetExpandedOp(InOp, Lo, Hi);
       Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
       Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
       return;
     case SplitVector:
       // Convert the split parts of the input if it was split in two.
       GetSplitVector(InOp, Lo, Hi);
       if (Lo.getValueType() == Hi.getValueType()) {
         if (TLI.isBigEndian())
           std::swap(Lo, Hi);
         Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
         Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
         return;
       }
       break;
     case ScalarizeVector:
       // Convert the element instead.
       SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
       Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
       Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
       return;
   }

   // Lower the bit-convert to a store/load from the stack, then expand the load.
   SDValue Op = CreateStackStoreLoad(InOp, N->getValueType(0));
   ExpandRes_NormalLoad(Op.getNode(), Lo, Hi);
 }

 void DAGTypeLegalizer::ExpandRes_BUILD_PAIR(SDNode *N, SDValue &Lo,
                                             SDValue &Hi) {
   // Return the operands.
   Lo = N->getOperand(0);
   Hi = N->getOperand(1);
 }

 void DAGTypeLegalizer::ExpandRes_EXTRACT_ELEMENT(SDNode *N, SDValue &Lo,
                                                  SDValue &Hi) {
   GetExpandedOp(N->getOperand(0), Lo, Hi);
   SDValue Part = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ?
                    Hi : Lo;

   assert(Part.getValueType() == N->getValueType(0) &&
          "Type twice as big as expanded type not itself expanded!");
   MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));

   Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part,
                    DAG.getConstant(0, TLI.getPointerTy()));
   Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part,
                    DAG.getConstant(1, TLI.getPointerTy()));
 }

 void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
                                                     SDValue &Hi) {
   SDValue OldVec = N->getOperand(0);
   unsigned OldElts = OldVec.getValueType().getVectorNumElements();

   // Convert to a vector of the expanded element type, for example
   // <3 x i64> -> <6 x i32>.
   MVT OldVT = N->getValueType(0);
   MVT NewVT = TLI.getTypeToTransformTo(OldVT);

   SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT,
                                  MVT::getVectorVT(NewVT, 2*OldElts),
                                  OldVec);

   // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
   SDValue Idx = N->getOperand(1);

   // Make sure the type of Idx is big enough to hold the new values.
   if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
     Idx = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), Idx);

   Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx, Idx);
   Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx);

   Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx,
                     DAG.getConstant(1, Idx.getValueType()));
   Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx);

   if (TLI.isBigEndian())
     std::swap(Lo, Hi);
 }

 void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo,
                                             SDValue &Hi) {
   assert(ISD::isNormalLoad(N) && "This routine only for normal loads!");

   LoadSDNode *LD = cast<LoadSDNode>(N);
   MVT NVT = TLI.getTypeToTransformTo(LD->getValueType(0));
   SDValue Chain = LD->getChain();
   SDValue Ptr = LD->getBasePtr();
   int SVOffset = LD->getSrcValueOffset();
   unsigned Alignment = LD->getAlignment();
   bool isVolatile = LD->isVolatile();

   assert(NVT.isByteSized() && "Expanded type not byte sized!");

   Lo = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset,
                    isVolatile, Alignment);

   // Increment the pointer to the other half.
   unsigned IncrementSize = NVT.getSizeInBits() / 8;
   Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
                     DAG.getIntPtrConstant(IncrementSize));
   Hi = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset+IncrementSize,
                    isVolatile, MinAlign(Alignment, IncrementSize));

   // Build a factor node to remember that this load is independent of the
   // other one.
   Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
                       Hi.getValue(1));

   // Handle endianness of the load.
   if (TLI.isBigEndian())
     std::swap(Lo, Hi);

   // Modified the chain - switch anything that used the old chain to use
   // the new one.
   ReplaceValueWith(SDValue(N, 1), Chain);
 }


 //===--------------------------------------------------------------------===//
 // Generic Operand Expansion.
 //===--------------------------------------------------------------------===//

 SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) {
   if (N->getValueType(0).isVector()) {
     // An illegal expanding type is being converted to a legal vector type.
     // Make a two element vector out of the expanded parts and convert that
     // instead, but only if the new vector type is legal (otherwise there
     // is no point, and it might create expansion loops).  For example, on
     // x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32.
     MVT OVT = N->getOperand(0).getValueType();
     MVT NVT = MVT::getVectorVT(TLI.getTypeToTransformTo(OVT), 2);

     if (isTypeLegal(NVT)) {
       SDValue Parts[2];
       GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]);

       if (TLI.isBigEndian())
         std::swap(Parts[0], Parts[1]);

       SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, NVT, Parts, 2);
       return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Vec);
     }
   }

   // Otherwise, store to a temporary and load out again as the new type.
   return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0));
 }

 SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) {
   // The vector type is legal but the element type needs expansion.
   MVT VecVT = N->getValueType(0);
   unsigned NumElts = VecVT.getVectorNumElements();
   MVT OldVT = N->getOperand(0).getValueType();
   MVT NewVT = TLI.getTypeToTransformTo(OldVT);

   // Build a vector of twice the length out of the expanded elements.
   // For example <3 x i64> -> <6 x i32>.
   std::vector<SDValue> NewElts;
   NewElts.reserve(NumElts*2);

   for (unsigned i = 0; i < NumElts; ++i) {
     SDValue Lo, Hi;
     GetExpandedOp(N->getOperand(i), Lo, Hi);
     if (TLI.isBigEndian())
       std::swap(Lo, Hi);
     NewElts.push_back(Lo);
     NewElts.push_back(Hi);
   }

   SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR,
                                  MVT::getVectorVT(NewVT, NewElts.size()),
                                  &NewElts[0], NewElts.size());

   // Convert the new vector to the old vector type.
   return DAG.getNode(ISD::BIT_CONVERT, VecVT, NewVec);
 }

 SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) {
   SDValue Lo, Hi;
   GetExpandedOp(N->getOperand(0), Lo, Hi);
   return cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ? Hi : Lo;
 }

 SDValue DAGTypeLegalizer::ExpandOp_NormalStore(SDNode *N, unsigned OpNo) {
   assert(ISD::isNormalStore(N) && "This routine only for normal stores!");
   assert(OpNo == 1 && "Can only expand the stored value so far");

   StoreSDNode *St = cast<StoreSDNode>(N);
   MVT NVT = TLI.getTypeToTransformTo(St->getValue().getValueType());
   SDValue Chain = St->getChain();
   SDValue Ptr = St->getBasePtr();
   int SVOffset = St->getSrcValueOffset();
   unsigned Alignment = St->getAlignment();
   bool isVolatile = St->isVolatile();

   assert(NVT.isByteSized() && "Expanded type not byte sized!");
   unsigned IncrementSize = NVT.getSizeInBits() / 8;

   SDValue Lo, Hi;
   GetExpandedOp(St->getValue(), Lo, Hi);

   if (TLI.isBigEndian())
     std::swap(Lo, Hi);

   Lo = DAG.getStore(Chain, Lo, Ptr, St->getSrcValue(), SVOffset,
                     isVolatile, Alignment);

   Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
                     DAG.getIntPtrConstant(IncrementSize));
   assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!");
   Hi = DAG.getStore(Chain, Hi, Ptr, St->getSrcValue(), SVOffset + IncrementSize,
                     isVolatile, MinAlign(Alignment, IncrementSize));

   return DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi);
 }


 //===--------------------------------------------------------------------===//
 // Generic Result Splitting.
 //===--------------------------------------------------------------------===//

 // Be careful to make no assumptions about which of Lo/Hi is stored first in
 // memory (for vectors it is always Lo first followed by Hi in the following
 // bytes; for integers and floats it is Lo first if and only if the machine is
 // little-endian).

 void DAGTypeLegalizer::SplitRes_MERGE_VALUES(SDNode *N,
                                              SDValue &Lo, SDValue &Hi) {
   // A MERGE_VALUES node can produce any number of values.  We know that the
   // first illegal one needs to be expanded into Lo/Hi.
   unsigned i;

   // The string of legal results gets turns into the input operands, which have
   // the same type.
   for (i = 0; isTypeLegal(N->getValueType(i)); ++i)
     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));

   // The first illegal result must be the one that needs to be expanded.
   GetSplitOp(N->getOperand(i), Lo, Hi);

   // Legalize the rest of the results into the input operands whether they are
   // legal or not.
   unsigned e = N->getNumValues();
   for (++i; i != e; ++i)
     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
 }

 void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo,
                                        SDValue &Hi) {
   SDValue LL, LH, RL, RH;
   GetSplitOp(N->getOperand(1), LL, LH);
   GetSplitOp(N->getOperand(2), RL, RH);

   SDValue Cond = N->getOperand(0);
   Lo = DAG.getNode(ISD::SELECT, LL.getValueType(), Cond, LL, RL);
   Hi = DAG.getNode(ISD::SELECT, LH.getValueType(), Cond, LH, RH);
 }

 void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
                                           SDValue &Hi) {
   SDValue LL, LH, RL, RH;
   GetSplitOp(N->getOperand(2), LL, LH);
   GetSplitOp(N->getOperand(3), RL, RH);

   Lo = DAG.getNode(ISD::SELECT_CC, LL.getValueType(), N->getOperand(0),
                    N->getOperand(1), LL, RL, N->getOperand(4));
   Hi = DAG.getNode(ISD::SELECT_CC, LH.getValueType(), N->getOperand(0),
                    N->getOperand(1), LH, RH, N->getOperand(4));
 }

 void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) {
   MVT LoVT, HiVT;
   GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
   Lo = DAG.getNode(ISD::UNDEF, LoVT);
   Hi = DAG.getNode(ISD::UNDEF, HiVT);
 }
	//===-------- LegalizeTypesGeneric.cpp - Generic type legalization --------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements generic type expansion and splitting for LegalizeTypes.
	// The routines here perform legalization when the details of the type (such as
	// whether it is an integer or a float) do not matter.
	// Expansion is the act of changing a computation in an illegal type to be a
	// computation in two identical registers of a smaller type.
	// Splitting is the act of changing a computation in an illegal type to be a
	// computation in two not necessarily identical registers of a smaller type.
	//
	//===----------------------------------------------------------------------===//

	#include "LegalizeTypes.h"
	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// Generic Result Expansion.
	//===----------------------------------------------------------------------===//

	// These routines assume that the Lo/Hi part is stored first in memory on
	// little/big-endian machines, followed by the Hi/Lo part. This means that
	// they cannot be used as is on vectors, for which Lo is always stored first.

	void DAGTypeLegalizer::ExpandRes_BIT_CONVERT(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));
	SDValue InOp = N->getOperand(0);
	MVT InVT = InOp.getValueType();

	// Handle some special cases efficiently.
	switch (getTypeAction(InVT)) {
	default:
	assert(false && "Unknown type action!");
	case Legal:
	case PromoteInteger:
	break;
	case SoftenFloat:
	// Convert the integer operand instead.
	SplitInteger(GetSoftenedFloat(InOp), Lo, Hi);
	Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
	Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
	return;
	case ExpandInteger:
	case ExpandFloat:
	// Convert the expanded pieces of the input.
	GetExpandedOp(InOp, Lo, Hi);
	Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
	Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
	return;
	case SplitVector:
	// Convert the split parts of the input if it was split in two.
	GetSplitVector(InOp, Lo, Hi);
	if (Lo.getValueType() == Hi.getValueType()) {
	if (TLI.isBigEndian())
	std::swap(Lo, Hi);
	Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
	Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
	return;
	}
	break;
	case ScalarizeVector:
	// Convert the element instead.
	SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
	Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo);
	Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi);
	return;
	}

	// Lower the bit-convert to a store/load from the stack, then expand the load.
	SDValue Op = CreateStackStoreLoad(InOp, N->getValueType(0));
	ExpandRes_NormalLoad(Op.getNode(), Lo, Hi);
	}

	void DAGTypeLegalizer::ExpandRes_BUILD_PAIR(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	// Return the operands.
	Lo = N->getOperand(0);
	Hi = N->getOperand(1);
	}

	void DAGTypeLegalizer::ExpandRes_EXTRACT_ELEMENT(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	GetExpandedOp(N->getOperand(0), Lo, Hi);
	SDValue Part = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ?
	Hi : Lo;

	assert(Part.getValueType() == N->getValueType(0) &&
	"Type twice as big as expanded type not itself expanded!");
	MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));

	Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part,
	DAG.getConstant(0, TLI.getPointerTy()));
	Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part,
	DAG.getConstant(1, TLI.getPointerTy()));
	}

	void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	SDValue OldVec = N->getOperand(0);
	unsigned OldElts = OldVec.getValueType().getVectorNumElements();

	// Convert to a vector of the expanded element type, for example
	// <3 x i64> -> <6 x i32>.
	MVT OldVT = N->getValueType(0);
	MVT NewVT = TLI.getTypeToTransformTo(OldVT);

	SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT,
	MVT::getVectorVT(NewVT, 2*OldElts),
	OldVec);

	// Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
	SDValue Idx = N->getOperand(1);

	// Make sure the type of Idx is big enough to hold the new values.
	if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
	Idx = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), Idx);

	Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx, Idx);
	Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx);

	Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx,
	DAG.getConstant(1, Idx.getValueType()));
	Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx);

	if (TLI.isBigEndian())
	std::swap(Lo, Hi);
	}

	void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	assert(ISD::isNormalLoad(N) && "This routine only for normal loads!");

	LoadSDNode *LD = cast<LoadSDNode>(N);
	MVT NVT = TLI.getTypeToTransformTo(LD->getValueType(0));
	SDValue Chain = LD->getChain();
	SDValue Ptr = LD->getBasePtr();
	int SVOffset = LD->getSrcValueOffset();
	unsigned Alignment = LD->getAlignment();
	bool isVolatile = LD->isVolatile();

	assert(NVT.isByteSized() && "Expanded type not byte sized!");

	Lo = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset,
	isVolatile, Alignment);

	// Increment the pointer to the other half.
	unsigned IncrementSize = NVT.getSizeInBits() / 8;
	Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
	DAG.getIntPtrConstant(IncrementSize));
	Hi = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset+IncrementSize,
	isVolatile, MinAlign(Alignment, IncrementSize));

	// Build a factor node to remember that this load is independent of the
	// other one.
	Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
	Hi.getValue(1));

	// Handle endianness of the load.
	if (TLI.isBigEndian())
	std::swap(Lo, Hi);

	// Modified the chain - switch anything that used the old chain to use
	// the new one.
	ReplaceValueWith(SDValue(N, 1), Chain);
	}


	//===--------------------------------------------------------------------===//
	// Generic Operand Expansion.
	//===--------------------------------------------------------------------===//

	SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) {
	if (N->getValueType(0).isVector()) {
	// An illegal expanding type is being converted to a legal vector type.
	// Make a two element vector out of the expanded parts and convert that
	// instead, but only if the new vector type is legal (otherwise there
	// is no point, and it might create expansion loops). For example, on
	// x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32.
	MVT OVT = N->getOperand(0).getValueType();
	MVT NVT = MVT::getVectorVT(TLI.getTypeToTransformTo(OVT), 2);

	if (isTypeLegal(NVT)) {
	SDValue Parts[2];
	GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]);

	if (TLI.isBigEndian())
	std::swap(Parts[0], Parts[1]);

	SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, NVT, Parts, 2);
	return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Vec);
	}
	}

	// Otherwise, store to a temporary and load out again as the new type.
	return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0));
	}

	SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) {
	// The vector type is legal but the element type needs expansion.
	MVT VecVT = N->getValueType(0);
	unsigned NumElts = VecVT.getVectorNumElements();
	MVT OldVT = N->getOperand(0).getValueType();
	MVT NewVT = TLI.getTypeToTransformTo(OldVT);

	// Build a vector of twice the length out of the expanded elements.
	// For example <3 x i64> -> <6 x i32>.
	std::vector<SDValue> NewElts;
	NewElts.reserve(NumElts*2);

	for (unsigned i = 0; i < NumElts; ++i) {
	SDValue Lo, Hi;
	GetExpandedOp(N->getOperand(i), Lo, Hi);
	if (TLI.isBigEndian())
	std::swap(Lo, Hi);
	NewElts.push_back(Lo);
	NewElts.push_back(Hi);
	}

	SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR,
	MVT::getVectorVT(NewVT, NewElts.size()),
	&NewElts[0], NewElts.size());

	// Convert the new vector to the old vector type.
	return DAG.getNode(ISD::BIT_CONVERT, VecVT, NewVec);
	}

	SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) {
	SDValue Lo, Hi;
	GetExpandedOp(N->getOperand(0), Lo, Hi);
	return cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ? Hi : Lo;
	}

	SDValue DAGTypeLegalizer::ExpandOp_NormalStore(SDNode *N, unsigned OpNo) {
	assert(ISD::isNormalStore(N) && "This routine only for normal stores!");
	assert(OpNo == 1 && "Can only expand the stored value so far");

	StoreSDNode *St = cast<StoreSDNode>(N);
	MVT NVT = TLI.getTypeToTransformTo(St->getValue().getValueType());
	SDValue Chain = St->getChain();
	SDValue Ptr = St->getBasePtr();
	int SVOffset = St->getSrcValueOffset();
	unsigned Alignment = St->getAlignment();
	bool isVolatile = St->isVolatile();

	assert(NVT.isByteSized() && "Expanded type not byte sized!");
	unsigned IncrementSize = NVT.getSizeInBits() / 8;

	SDValue Lo, Hi;
	GetExpandedOp(St->getValue(), Lo, Hi);

	if (TLI.isBigEndian())
	std::swap(Lo, Hi);

	Lo = DAG.getStore(Chain, Lo, Ptr, St->getSrcValue(), SVOffset,
	isVolatile, Alignment);

	Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
	DAG.getIntPtrConstant(IncrementSize));
	assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!");
	Hi = DAG.getStore(Chain, Hi, Ptr, St->getSrcValue(), SVOffset + IncrementSize,
	isVolatile, MinAlign(Alignment, IncrementSize));

	return DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi);
	}


	//===--------------------------------------------------------------------===//
	// Generic Result Splitting.
	//===--------------------------------------------------------------------===//

	// Be careful to make no assumptions about which of Lo/Hi is stored first in
	// memory (for vectors it is always Lo first followed by Hi in the following
	// bytes; for integers and floats it is Lo first if and only if the machine is
	// little-endian).

	void DAGTypeLegalizer::SplitRes_MERGE_VALUES(SDNode *N,
	SDValue &Lo, SDValue &Hi) {
	// A MERGE_VALUES node can produce any number of values. We know that the
	// first illegal one needs to be expanded into Lo/Hi.
	unsigned i;

	// The string of legal results gets turns into the input operands, which have
	// the same type.
	for (i = 0; isTypeLegal(N->getValueType(i)); ++i)
	ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));

	// The first illegal result must be the one that needs to be expanded.
	GetSplitOp(N->getOperand(i), Lo, Hi);

	// Legalize the rest of the results into the input operands whether they are
	// legal or not.
	unsigned e = N->getNumValues();
	for (++i; i != e; ++i)
	ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
	}

	void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	SDValue LL, LH, RL, RH;
	GetSplitOp(N->getOperand(1), LL, LH);
	GetSplitOp(N->getOperand(2), RL, RH);

	SDValue Cond = N->getOperand(0);
	Lo = DAG.getNode(ISD::SELECT, LL.getValueType(), Cond, LL, RL);
	Hi = DAG.getNode(ISD::SELECT, LH.getValueType(), Cond, LH, RH);
	}

	void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
	SDValue &Hi) {
	SDValue LL, LH, RL, RH;
	GetSplitOp(N->getOperand(2), LL, LH);
	GetSplitOp(N->getOperand(3), RL, RH);

	Lo = DAG.getNode(ISD::SELECT_CC, LL.getValueType(), N->getOperand(0),
	N->getOperand(1), LL, RL, N->getOperand(4));
	Hi = DAG.getNode(ISD::SELECT_CC, LH.getValueType(), N->getOperand(0),
	N->getOperand(1), LH, RH, N->getOperand(4));
	}

	void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) {
	MVT LoVT, HiVT;
	GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
	Lo = DAG.getNode(ISD::UNDEF, LoVT);
	Hi = DAG.getNode(ISD::UNDEF, HiVT);
	}