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//===-- ARMSelectionDAGInfo.cpp - ARM 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 ARMSelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "arm-selectiondag-info"
#include "ARMTargetMachine.h"
using namespace llvm;
ARMSelectionDAGInfo::ARMSelectionDAGInfo(const TargetMachine &TM)
: TargetSelectionDAGInfo(TM),
Subtarget(&TM.getSubtarget<ARMSubtarget>()) {
}
ARMSelectionDAGInfo::~ARMSelectionDAGInfo() {
}
SDValue
ARMSelectionDAGInfo::EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl,
SDValue Chain,
SDValue Dst, SDValue Src,
SDValue Size, unsigned Align,
bool isVolatile, bool AlwaysInline,
MachinePointerInfo DstPtrInfo,
MachinePointerInfo SrcPtrInfo) const {
// Do repeated 4-byte loads and stores. To be improved.
// This requires 4-byte alignment.
if ((Align & 3) != 0)
return SDValue();
// This requires the copy size to be a constant, preferrably
// within a subtarget-specific limit.
ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
if (!ConstantSize)
return SDValue();
uint64_t SizeVal = ConstantSize->getZExtValue();
if (!AlwaysInline && SizeVal > Subtarget->getMaxInlineSizeThreshold())
return SDValue();
unsigned BytesLeft = SizeVal & 3;
unsigned NumMemOps = SizeVal >> 2;
unsigned EmittedNumMemOps = 0;
EVT VT = MVT::i32;
unsigned VTSize = 4;
unsigned i = 0;
const unsigned MAX_LOADS_IN_LDM = 6;
SDValue TFOps[MAX_LOADS_IN_LDM];
SDValue Loads[MAX_LOADS_IN_LDM];
uint64_t SrcOff = 0, DstOff = 0;
// Emit up to MAX_LOADS_IN_LDM loads, then a TokenFactor barrier, then the
// same number of stores. The loads and stores will get combined into
// ldm/stm later on.
while (EmittedNumMemOps < NumMemOps) {
for (i = 0;
i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
Loads[i] = DAG.getLoad(VT, dl, Chain,
DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
DAG.getConstant(SrcOff, MVT::i32)),
SrcPtrInfo.getWithOffset(SrcOff), isVolatile,
false, 0);
TFOps[i] = Loads[i].getValue(1);
SrcOff += VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
for (i = 0;
i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
DAG.getConstant(DstOff, MVT::i32)),
DstPtrInfo.getWithOffset(DstOff),
isVolatile, false, 0);
DstOff += VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
EmittedNumMemOps += i;
}
if (BytesLeft == 0)
return Chain;
// Issue loads / stores for the trailing (1 - 3) bytes.
unsigned BytesLeftSave = BytesLeft;
i = 0;
while (BytesLeft) {
if (BytesLeft >= 2) {
VT = MVT::i16;
VTSize = 2;
} else {
VT = MVT::i8;
VTSize = 1;
}
Loads[i] = DAG.getLoad(VT, dl, Chain,
DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
DAG.getConstant(SrcOff, MVT::i32)),
SrcPtrInfo.getWithOffset(SrcOff), false, false, 0);
TFOps[i] = Loads[i].getValue(1);
++i;
SrcOff += VTSize;
BytesLeft -= VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
i = 0;
BytesLeft = BytesLeftSave;
while (BytesLeft) {
if (BytesLeft >= 2) {
VT = MVT::i16;
VTSize = 2;
} else {
VT = MVT::i8;
VTSize = 1;
}
TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
DAG.getConstant(DstOff, MVT::i32)),
DstPtrInfo.getWithOffset(DstOff), false, false, 0);
++i;
DstOff += VTSize;
BytesLeft -= VTSize;
}
return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
}
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