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//===-- SystemZSelectionDAGInfo.cpp - SystemZ 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 SystemZSelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "systemz-selectiondag-info"
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/SelectionDAG.h"
using namespace llvm;
SystemZSelectionDAGInfo::
SystemZSelectionDAGInfo(const SystemZTargetMachine &TM)
: TargetSelectionDAGInfo(TM) {
}
SystemZSelectionDAGInfo::~SystemZSelectionDAGInfo() {
}
SDValue SystemZSelectionDAGInfo::
EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc DL, SDValue Chain,
SDValue Dst, SDValue Src, SDValue Size, unsigned Align,
bool IsVolatile, bool AlwaysInline,
MachinePointerInfo DstPtrInfo,
MachinePointerInfo SrcPtrInfo) const {
if (IsVolatile)
return SDValue();
if (ConstantSDNode *CSize = dyn_cast<ConstantSDNode>(Size)) {
uint64_t Bytes = CSize->getZExtValue();
if (Bytes >= 1 && Bytes <= 0x100) {
// A single MVC.
return DAG.getNode(SystemZISD::MVC, DL, MVT::Other,
Chain, Dst, Src, Size);
}
}
return SDValue();
}
// Handle a memset of 1, 2, 4 or 8 bytes with the operands given by
// Chain, Dst, ByteVal and Size. These cases are expected to use
// MVI, MVHHI, MVHI and MVGHI respectively.
static SDValue memsetStore(SelectionDAG &DAG, SDLoc DL, SDValue Chain,
SDValue Dst, uint64_t ByteVal, uint64_t Size,
unsigned Align,
MachinePointerInfo DstPtrInfo) {
uint64_t StoreVal = ByteVal;
for (unsigned I = 1; I < Size; ++I)
StoreVal |= ByteVal << (I * 8);
return DAG.getStore(Chain, DL,
DAG.getConstant(StoreVal, MVT::getIntegerVT(Size * 8)),
Dst, DstPtrInfo, false, false, Align);
}
SDValue SystemZSelectionDAGInfo::
EmitTargetCodeForMemset(SelectionDAG &DAG, SDLoc DL, SDValue Chain,
SDValue Dst, SDValue Byte, SDValue Size,
unsigned Align, bool IsVolatile,
MachinePointerInfo DstPtrInfo) const {
EVT DstVT = Dst.getValueType();
if (IsVolatile)
return SDValue();
if (ConstantSDNode *CSize = dyn_cast<ConstantSDNode>(Size)) {
uint64_t Bytes = CSize->getZExtValue();
if (Bytes == 0)
return SDValue();
if (ConstantSDNode *CByte = dyn_cast<ConstantSDNode>(Byte)) {
// Handle cases that can be done using at most two of
// MVI, MVHI, MVHHI and MVGHI. The latter two can only be
// used if ByteVal is all zeros or all ones; in other casees,
// we can move at most 2 halfwords.
uint64_t ByteVal = CByte->getZExtValue();
if (ByteVal == 0 || ByteVal == 255 ?
Bytes <= 16 && CountPopulation_64(Bytes) <= 2 :
Bytes <= 4) {
unsigned Size1 = Bytes == 16 ? 8 : 1 << findLastSet(Bytes);
unsigned Size2 = Bytes - Size1;
SDValue Chain1 = memsetStore(DAG, DL, Chain, Dst, ByteVal, Size1,
Align, DstPtrInfo);
if (Size2 == 0)
return Chain1;
Dst = DAG.getNode(ISD::ADD, DL, DstVT, Dst,
DAG.getConstant(Size1, DstVT));
DstPtrInfo = DstPtrInfo.getWithOffset(Size1);
SDValue Chain2 = memsetStore(DAG, DL, Chain, Dst, ByteVal, Size2,
std::min(Align, Size1), DstPtrInfo);
return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chain1, Chain2);
}
} else {
// Handle one and two bytes using STC.
if (Bytes <= 2) {
SDValue Chain1 = DAG.getStore(Chain, DL, Byte, Dst, DstPtrInfo,
false, false, Align);
if (Bytes == 1)
return Chain1;
SDValue Dst2 = DAG.getNode(ISD::ADD, DL, DstVT, Dst,
DAG.getConstant(1, DstVT));
SDValue Chain2 = DAG.getStore(Chain, DL, Byte, Dst2,
DstPtrInfo.getWithOffset(1),
false, false, 1);
return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chain1, Chain2);
}
}
assert(Bytes >= 2 && "Should have dealt with 0- and 1-byte cases already");
if (Bytes <= 0x101) {
// Copy the byte to the first location and then use MVC to copy
// it to the rest.
Chain = DAG.getStore(Chain, DL, Byte, Dst, DstPtrInfo,
false, false, Align);
SDValue Dst2 = DAG.getNode(ISD::ADD, DL, DstVT, Dst,
DAG.getConstant(1, DstVT));
return DAG.getNode(SystemZISD::MVC, DL, MVT::Other, Chain, Dst2, Dst,
DAG.getConstant(Bytes - 1, MVT::i32));
}
}
return SDValue();
}
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