llvm-6502/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
Chandler Carruth 0b8c9a80f2 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 11:36:10 +00:00

526 lines
21 KiB
C++

//===-------- 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. The Lo/Hi part
// is required to be stored first in memory on little/big-endian machines.
// 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.
// There are no requirements on how the type is represented in memory.
//
//===----------------------------------------------------------------------===//
#include "LegalizeTypes.h"
#include "llvm/IR/DataLayout.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_MERGE_VALUES(SDNode *N, unsigned ResNo,
SDValue &Lo, SDValue &Hi) {
SDValue Op = DisintegrateMERGE_VALUES(N, ResNo);
GetExpandedOp(Op, Lo, Hi);
}
void DAGTypeLegalizer::ExpandRes_BITCAST(SDNode *N, SDValue &Lo, SDValue &Hi) {
EVT OutVT = N->getValueType(0);
EVT NOutVT = TLI.getTypeToTransformTo(*DAG.getContext(), OutVT);
SDValue InOp = N->getOperand(0);
EVT InVT = InOp.getValueType();
DebugLoc dl = N->getDebugLoc();
// Handle some special cases efficiently.
switch (getTypeAction(InVT)) {
case TargetLowering::TypeLegal:
case TargetLowering::TypePromoteInteger:
break;
case TargetLowering::TypeSoftenFloat:
// Convert the integer operand instead.
SplitInteger(GetSoftenedFloat(InOp), Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
case TargetLowering::TypeExpandInteger:
case TargetLowering::TypeExpandFloat:
// Convert the expanded pieces of the input.
GetExpandedOp(InOp, Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
case TargetLowering::TypeSplitVector:
GetSplitVector(InOp, Lo, Hi);
if (TLI.isBigEndian())
std::swap(Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
case TargetLowering::TypeScalarizeVector:
// Convert the element instead.
SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
case TargetLowering::TypeWidenVector: {
assert(!(InVT.getVectorNumElements() & 1) && "Unsupported BITCAST");
InOp = GetWidenedVector(InOp);
EVT InNVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(),
InVT.getVectorNumElements()/2);
Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
DAG.getIntPtrConstant(0));
Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
if (TLI.isBigEndian())
std::swap(Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
}
}
if (InVT.isVector() && OutVT.isInteger()) {
// Handle cases like i64 = BITCAST v1i64 on x86, where the operand
// is legal but the result is not.
unsigned NumElems = 2;
EVT ElemVT = NOutVT;
EVT NVT = EVT::getVectorVT(*DAG.getContext(), ElemVT, NumElems);
// If <ElemVT * N> is not a legal type, try <ElemVT/2 * (N*2)>.
while (!isTypeLegal(NVT)) {
unsigned NewSizeInBits = ElemVT.getSizeInBits() / 2;
// If the element size is smaller than byte, bail.
if (NewSizeInBits < 8)
break;
NumElems *= 2;
ElemVT = EVT::getIntegerVT(*DAG.getContext(), NewSizeInBits);
NVT = EVT::getVectorVT(*DAG.getContext(), ElemVT, NumElems);
}
if (isTypeLegal(NVT)) {
SDValue CastInOp = DAG.getNode(ISD::BITCAST, dl, NVT, InOp);
SmallVector<SDValue, 8> Vals;
for (unsigned i = 0; i < NumElems; ++i)
Vals.push_back(DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, ElemVT,
CastInOp, DAG.getIntPtrConstant(i)));
// Build Lo, Hi pair by pairing extracted elements if needed.
unsigned Slot = 0;
for (unsigned e = Vals.size(); e - Slot > 2; Slot += 2, e += 1) {
// Each iteration will BUILD_PAIR two nodes and append the result until
// there are only two nodes left, i.e. Lo and Hi.
SDValue LHS = Vals[Slot];
SDValue RHS = Vals[Slot + 1];
if (TLI.isBigEndian())
std::swap(LHS, RHS);
Vals.push_back(DAG.getNode(ISD::BUILD_PAIR, dl,
EVT::getIntegerVT(
*DAG.getContext(),
LHS.getValueType().getSizeInBits() << 1),
LHS, RHS));
}
Lo = Vals[Slot++];
Hi = Vals[Slot++];
if (TLI.isBigEndian())
std::swap(Lo, Hi);
return;
}
}
// Lower the bit-convert to a store/load from the stack.
assert(NOutVT.isByteSized() && "Expanded type not byte sized!");
// Create the stack frame object. Make sure it is aligned for both
// the source and expanded destination types.
unsigned Alignment =
TLI.getDataLayout()->getPrefTypeAlignment(NOutVT.
getTypeForEVT(*DAG.getContext()));
SDValue StackPtr = DAG.CreateStackTemporary(InVT, Alignment);
int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(SPFI);
// Emit a store to the stack slot.
SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, InOp, StackPtr, PtrInfo,
false, false, 0);
// Load the first half from the stack slot.
Lo = DAG.getLoad(NOutVT, dl, Store, StackPtr, PtrInfo,
false, false, false, 0);
// Increment the pointer to the other half.
unsigned IncrementSize = NOutVT.getSizeInBits() / 8;
StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
DAG.getIntPtrConstant(IncrementSize));
// Load the second half from the stack slot.
Hi = DAG.getLoad(NOutVT, dl, Store, StackPtr,
PtrInfo.getWithOffset(IncrementSize), false,
false, false, MinAlign(Alignment, IncrementSize));
// Handle endianness of the load.
if (TLI.isBigEndian())
std::swap(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!");
GetPairElements(Part, Lo, Hi);
}
void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
SDValue &Hi) {
SDValue OldVec = N->getOperand(0);
unsigned OldElts = OldVec.getValueType().getVectorNumElements();
EVT OldEltVT = OldVec.getValueType().getVectorElementType();
DebugLoc dl = N->getDebugLoc();
// Convert to a vector of the expanded element type, for example
// <3 x i64> -> <6 x i32>.
EVT OldVT = N->getValueType(0);
EVT NewVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldVT);
if (OldVT != OldEltVT) {
// The result of EXTRACT_VECTOR_ELT may be larger than the element type of
// the input vector. If so, extend the elements of the input vector to the
// same bitwidth as the result before expanding.
assert(OldEltVT.bitsLT(OldVT) && "Result type smaller then element type!");
EVT NVecVT = EVT::getVectorVT(*DAG.getContext(), OldVT, OldElts);
OldVec = DAG.getNode(ISD::ANY_EXTEND, dl, NVecVT, N->getOperand(0));
}
SDValue NewVec = DAG.getNode(ISD::BITCAST, dl,
EVT::getVectorVT(*DAG.getContext(),
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, dl, TLI.getPointerTy(), Idx);
Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
DAG.getConstant(1, Idx.getValueType()));
Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, 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!");
DebugLoc dl = N->getDebugLoc();
LoadSDNode *LD = cast<LoadSDNode>(N);
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), LD->getValueType(0));
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
unsigned Alignment = LD->getAlignment();
bool isVolatile = LD->isVolatile();
bool isNonTemporal = LD->isNonTemporal();
bool isInvariant = LD->isInvariant();
assert(NVT.isByteSized() && "Expanded type not byte sized!");
Lo = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getPointerInfo(),
isVolatile, isNonTemporal, isInvariant, Alignment);
// Increment the pointer to the other half.
unsigned IncrementSize = NVT.getSizeInBits() / 8;
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(IncrementSize));
Hi = DAG.getLoad(NVT, dl, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
isVolatile, isNonTemporal, isInvariant,
MinAlign(Alignment, IncrementSize));
// Build a factor node to remember that this load is independent of the
// other one.
Chain = DAG.getNode(ISD::TokenFactor, dl, 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);
}
void DAGTypeLegalizer::ExpandRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
EVT OVT = N->getValueType(0);
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), OVT);
SDValue Chain = N->getOperand(0);
SDValue Ptr = N->getOperand(1);
DebugLoc dl = N->getDebugLoc();
const unsigned Align = N->getConstantOperandVal(3);
Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, N->getOperand(2), Align);
Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, N->getOperand(2), 0);
// 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), Hi.getValue(1));
}
//===--------------------------------------------------------------------===//
// Generic Operand Expansion.
//===--------------------------------------------------------------------===//
SDValue DAGTypeLegalizer::ExpandOp_BITCAST(SDNode *N) {
DebugLoc dl = N->getDebugLoc();
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 = BITCAST i64 into v1i64 = BITCAST v2i32.
EVT OVT = N->getOperand(0).getValueType();
EVT NVT = EVT::getVectorVT(*DAG.getContext(),
TLI.getTypeToTransformTo(*DAG.getContext(), 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, dl, NVT, Parts, 2);
return DAG.getNode(ISD::BITCAST, dl, 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.
EVT VecVT = N->getValueType(0);
unsigned NumElts = VecVT.getVectorNumElements();
EVT OldVT = N->getOperand(0).getValueType();
EVT NewVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldVT);
DebugLoc dl = N->getDebugLoc();
assert(OldVT == VecVT.getVectorElementType() &&
"BUILD_VECTOR operand type doesn't match vector element type!");
// 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, dl,
EVT::getVectorVT(*DAG.getContext(),
NewVT, NewElts.size()),
&NewElts[0], NewElts.size());
// Convert the new vector to the old vector type.
return DAG.getNode(ISD::BITCAST, dl, 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_INSERT_VECTOR_ELT(SDNode *N) {
// The vector type is legal but the element type needs expansion.
EVT VecVT = N->getValueType(0);
unsigned NumElts = VecVT.getVectorNumElements();
DebugLoc dl = N->getDebugLoc();
SDValue Val = N->getOperand(1);
EVT OldEVT = Val.getValueType();
EVT NewEVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldEVT);
assert(OldEVT == VecVT.getVectorElementType() &&
"Inserted element type doesn't match vector element type!");
// Bitconvert to a vector of twice the length with elements of the expanded
// type, insert the expanded vector elements, and then convert back.
EVT NewVecVT = EVT::getVectorVT(*DAG.getContext(), NewEVT, NumElts*2);
SDValue NewVec = DAG.getNode(ISD::BITCAST, dl,
NewVecVT, N->getOperand(0));
SDValue Lo, Hi;
GetExpandedOp(Val, Lo, Hi);
if (TLI.isBigEndian())
std::swap(Lo, Hi);
SDValue Idx = N->getOperand(2);
Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
NewVec = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Lo, Idx);
Idx = DAG.getNode(ISD::ADD, dl,
Idx.getValueType(), Idx, DAG.getIntPtrConstant(1));
NewVec = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Hi, Idx);
// Convert the new vector to the old vector type.
return DAG.getNode(ISD::BITCAST, dl, VecVT, NewVec);
}
SDValue DAGTypeLegalizer::ExpandOp_SCALAR_TO_VECTOR(SDNode *N) {
DebugLoc dl = N->getDebugLoc();
EVT VT = N->getValueType(0);
assert(VT.getVectorElementType() == N->getOperand(0).getValueType() &&
"SCALAR_TO_VECTOR operand type doesn't match vector element type!");
unsigned NumElts = VT.getVectorNumElements();
SmallVector<SDValue, 16> Ops(NumElts);
Ops[0] = N->getOperand(0);
SDValue UndefVal = DAG.getUNDEF(Ops[0].getValueType());
for (unsigned i = 1; i < NumElts; ++i)
Ops[i] = UndefVal;
return DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Ops[0], NumElts);
}
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");
DebugLoc dl = N->getDebugLoc();
StoreSDNode *St = cast<StoreSDNode>(N);
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(),
St->getValue().getValueType());
SDValue Chain = St->getChain();
SDValue Ptr = St->getBasePtr();
unsigned Alignment = St->getAlignment();
bool isVolatile = St->isVolatile();
bool isNonTemporal = St->isNonTemporal();
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, dl, Lo, Ptr, St->getPointerInfo(),
isVolatile, isNonTemporal, Alignment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(IncrementSize));
assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!");
Hi = DAG.getStore(Chain, dl, Hi, Ptr,
St->getPointerInfo().getWithOffset(IncrementSize),
isVolatile, isNonTemporal,
MinAlign(Alignment, IncrementSize));
return DAG.getNode(ISD::TokenFactor, dl, 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, unsigned ResNo,
SDValue &Lo, SDValue &Hi) {
SDValue Op = DisintegrateMERGE_VALUES(N, ResNo);
GetSplitOp(Op, Lo, Hi);
}
void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo,
SDValue &Hi) {
SDValue LL, LH, RL, RH, CL, CH;
DebugLoc dl = N->getDebugLoc();
GetSplitOp(N->getOperand(1), LL, LH);
GetSplitOp(N->getOperand(2), RL, RH);
SDValue Cond = N->getOperand(0);
CL = CH = Cond;
if (Cond.getValueType().isVector()) {
assert(Cond.getValueType().getVectorElementType() == MVT::i1 &&
"Condition legalized before result?");
unsigned NumElements = Cond.getValueType().getVectorNumElements();
EVT VCondTy = EVT::getVectorVT(*DAG.getContext(), MVT::i1, NumElements / 2);
CL = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VCondTy, Cond,
DAG.getIntPtrConstant(0));
CH = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VCondTy, Cond,
DAG.getIntPtrConstant(NumElements / 2));
}
Lo = DAG.getNode(N->getOpcode(), dl, LL.getValueType(), CL, LL, RL);
Hi = DAG.getNode(N->getOpcode(), dl, LH.getValueType(), CH, LH, RH);
}
void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
SDValue &Hi) {
SDValue LL, LH, RL, RH;
DebugLoc dl = N->getDebugLoc();
GetSplitOp(N->getOperand(2), LL, LH);
GetSplitOp(N->getOperand(3), RL, RH);
Lo = DAG.getNode(ISD::SELECT_CC, dl, LL.getValueType(), N->getOperand(0),
N->getOperand(1), LL, RL, N->getOperand(4));
Hi = DAG.getNode(ISD::SELECT_CC, dl, LH.getValueType(), N->getOperand(0),
N->getOperand(1), LH, RH, N->getOperand(4));
}
void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) {
EVT LoVT, HiVT;
GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
Lo = DAG.getUNDEF(LoVT);
Hi = DAG.getUNDEF(HiVT);
}