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MEMSET / MEMCPY lowering bugs: we can't issue a single WORD / DWORD version of

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rep/stos and rep/mov if the count is not a constant. We could do
  rep/stosl; and $count, 3; rep/stosb
For now, I will lower them to memset / memcpy calls. We will revisit this after
a little bit experiment.

Also need to take care of the trailing bytes even if the count is a constant.
Since the max. number of trailing bytes are 3, we will simply issue loads /
stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26517 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2006-03-04 02:48:56 +00:00
parent 973e0ef839
commit 62bec2ca4c
1 changed files with 83 additions and 28 deletions
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111
lib/Target/X86/X86ISelLowering.cpp
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@ -1696,7 +1696,7 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
Op.getOperand(0), Op.getOperand(2), CC, Cond);
}
case ISD::MEMSET: {
SDOperand InFlag;
SDOperand InFlag(0, 0);
SDOperand Chain = Op.getOperand(0);
unsigned Align =
(unsigned)cast<ConstantSDNode>(Op.getOperand(4))->getValue();
@ -1705,7 +1705,7 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3));
// If not DWORD aligned, call memset if size is less than the threshold.
// It knows how to align to the right boundary first.
if ((Align & 3) != 0 &&
if ((Align & 3) != 0 ||
!(I && I->getValue() >= Subtarget->getMinRepStrSizeThreshold())) {
MVT::ValueType IntPtr = getPointerTy();
const Type *IntPtrTy = getTargetData().getIntPtrType();
@ -1723,7 +1723,9 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
MVT::ValueType AVT;
SDOperand Count;
if (ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Op.getOperand(2))) {
ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Op.getOperand(2));
unsigned BytesLeft = 0;
if (ValC) {
unsigned ValReg;
unsigned Val = ValC->getValue() & 255;
@ -1731,21 +1733,15 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
switch (Align & 3) {
case 2: // WORD aligned
AVT = MVT::i16;
if (I)
Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
else
Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
DAG.getConstant(1, MVT::i8));
Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
BytesLeft = I->getValue() % 2;
Val = (Val << 8) | Val;
ValReg = X86::AX;
break;
case 0: // DWORD aligned
AVT = MVT::i32;
if (I)
Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
else
Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
DAG.getConstant(2, MVT::i8));
Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
BytesLeft = I->getValue() % 4;
Val = (Val << 8) | Val;
Val = (Val << 16) | Val;
ValReg = X86::EAX;
@ -1771,9 +1767,36 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, X86::EDI, Op.getOperand(1), InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getNode(X86ISD::REP_STOS, MVT::Other, Chain,
DAG.getValueType(AVT), InFlag);
return DAG.getNode(X86ISD::REP_STOS, MVT::Other, Chain,
DAG.getValueType(AVT), InFlag);
if (BytesLeft) {
// Issue stores for the last 1 - 3 bytes.
SDOperand Value;
unsigned Val = ValC->getValue() & 255;
unsigned Offset = I->getValue() - BytesLeft;
SDOperand DstAddr = Op.getOperand(1);
MVT::ValueType AddrVT = DstAddr.getValueType();
if (BytesLeft >= 2) {
Value = DAG.getConstant((Val << 8) | Val, MVT::i16);
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
DAG.getNode(ISD::ADD, AddrVT, DstAddr,
DAG.getConstant(Offset, AddrVT)),
DAG.getSrcValue(NULL));
BytesLeft -= 2;
Offset += 2;
}
if (BytesLeft == 1) {
Value = DAG.getConstant(Val, MVT::i8);
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
DAG.getNode(ISD::ADD, AddrVT, DstAddr,
DAG.getConstant(Offset, AddrVT)),
DAG.getSrcValue(NULL));
}
}
return Chain;
}
case ISD::MEMCPY: {
SDOperand Chain = Op.getOperand(0);
@ -1784,7 +1807,7 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3));
// If not DWORD aligned, call memcpy if size is less than the threshold.
// It knows how to align to the right boundary first.
if ((Align & 3) != 0 &&
if ((Align & 3) != 0 ||
!(I && I->getValue() >= Subtarget->getMinRepStrSizeThreshold())) {
MVT::ValueType IntPtr = getPointerTy();
const Type *IntPtrTy = getTargetData().getIntPtrType();
@ -1800,21 +1823,17 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
MVT::ValueType AVT;
SDOperand Count;
unsigned BytesLeft = 0;
switch (Align & 3) {
case 2: // WORD aligned
AVT = MVT::i16;
if (I)
Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
else
Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
Count = DAG.getConstant(I->getValue() / 2, MVT::i32);
BytesLeft = I->getValue() % 2;
break;
case 0: // DWORD aligned
AVT = MVT::i32;
if (I)
Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
else
Count = DAG.getNode(ISD::SRL, MVT::i32, Op.getOperand(3),
DAG.getConstant(2, MVT::i8));
Count = DAG.getConstant(I->getValue() / 4, MVT::i32);
BytesLeft = I->getValue() % 4;
break;
default: // Byte aligned
AVT = MVT::i8;
@ -1822,16 +1841,52 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
break;
}
SDOperand InFlag;
SDOperand InFlag(0, 0);
Chain = DAG.getCopyToReg(Chain, X86::ECX, Count, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, X86::EDI, Op.getOperand(1), InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, X86::ESI, Op.getOperand(2), InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getNode(X86ISD::REP_MOVS, MVT::Other, Chain,
DAG.getValueType(AVT), InFlag);
return DAG.getNode(X86ISD::REP_MOVS, MVT::Other, Chain,
DAG.getValueType(AVT), InFlag);
if (BytesLeft) {
// Issue loads and stores for the last 1 - 3 bytes.
unsigned Offset = I->getValue() - BytesLeft;
SDOperand DstAddr = Op.getOperand(1);
MVT::ValueType DstVT = DstAddr.getValueType();
SDOperand SrcAddr = Op.getOperand(2);
MVT::ValueType SrcVT = SrcAddr.getValueType();
SDOperand Value;
if (BytesLeft >= 2) {
Value = DAG.getLoad(MVT::i16, Chain,
DAG.getNode(ISD::ADD, SrcVT, SrcAddr,
DAG.getConstant(Offset, SrcVT)),
DAG.getSrcValue(NULL));
Chain = Value.getValue(1);
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
DAG.getNode(ISD::ADD, DstVT, DstAddr,
DAG.getConstant(Offset, DstVT)),
DAG.getSrcValue(NULL));
BytesLeft -= 2;
Offset += 2;
}
if (BytesLeft == 1) {
Value = DAG.getLoad(MVT::i8, Chain,
DAG.getNode(ISD::ADD, SrcVT, SrcAddr,
DAG.getConstant(Offset, SrcVT)),
DAG.getSrcValue(NULL));
Chain = Value.getValue(1);
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
DAG.getNode(ISD::ADD, DstVT, DstAddr,
DAG.getConstant(Offset, DstVT)),
DAG.getSrcValue(NULL));
}
}
return Chain;
}
// ConstantPool, GlobalAddress, and ExternalSymbol are lowered as their