llvm/lib/Target/R600/R600MachineScheduler.cpp
2013-03-11 08:19:28 +00:00

489 lines
13 KiB
C++

//===-- R600MachineScheduler.cpp - R600 Scheduler Interface -*- C++ -*-----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief R600 Machine Scheduler interface
// TODO: Scheduling is optimised for VLIW4 arch, modify it to support TRANS slot
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "misched"
#include "R600MachineScheduler.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/Support/raw_ostream.h"
#include <set>
using namespace llvm;
void R600SchedStrategy::initialize(ScheduleDAGMI *dag) {
DAG = dag;
TII = static_cast<const R600InstrInfo*>(DAG->TII);
TRI = static_cast<const R600RegisterInfo*>(DAG->TRI);
MRI = &DAG->MRI;
Available[IDAlu]->clear();
Available[IDFetch]->clear();
Available[IDOther]->clear();
CurInstKind = IDOther;
CurEmitted = 0;
OccupedSlotsMask = 15;
memset(InstructionsGroupCandidate, 0, sizeof(InstructionsGroupCandidate));
InstKindLimit[IDAlu] = 120; // 120 minus 8 for security
const AMDGPUSubtarget &ST = DAG->TM.getSubtarget<AMDGPUSubtarget>();
if (ST.device()->getGeneration() <= AMDGPUDeviceInfo::HD5XXX) {
InstKindLimit[IDFetch] = 7; // 8 minus 1 for security
} else {
InstKindLimit[IDFetch] = 15; // 16 minus 1 for security
}
}
void R600SchedStrategy::MoveUnits(ReadyQueue *QSrc, ReadyQueue *QDst)
{
if (QSrc->empty())
return;
for (ReadyQueue::iterator I = QSrc->begin(),
E = QSrc->end(); I != E; ++I) {
(*I)->NodeQueueId &= ~QSrc->getID();
QDst->push(*I);
}
QSrc->clear();
}
SUnit* R600SchedStrategy::pickNode(bool &IsTopNode) {
SUnit *SU = 0;
IsTopNode = true;
NextInstKind = IDOther;
// check if we might want to switch current clause type
bool AllowSwitchToAlu = (CurInstKind == IDOther) ||
(CurEmitted > InstKindLimit[CurInstKind]) ||
(Available[CurInstKind]->empty());
bool AllowSwitchFromAlu = (CurEmitted > InstKindLimit[CurInstKind]) &&
(!Available[IDFetch]->empty() || !Available[IDOther]->empty());
if ((AllowSwitchToAlu && CurInstKind != IDAlu) ||
(!AllowSwitchFromAlu && CurInstKind == IDAlu)) {
// try to pick ALU
SU = pickAlu();
if (SU) {
if (CurEmitted > InstKindLimit[IDAlu])
CurEmitted = 0;
NextInstKind = IDAlu;
}
}
if (!SU) {
// try to pick FETCH
SU = pickOther(IDFetch);
if (SU)
NextInstKind = IDFetch;
}
// try to pick other
if (!SU) {
SU = pickOther(IDOther);
if (SU)
NextInstKind = IDOther;
}
DEBUG(
if (SU) {
dbgs() << "picked node: ";
SU->dump(DAG);
} else {
dbgs() << "NO NODE ";
for (int i = 0; i < IDLast; ++i) {
Available[i]->dump();
Pending[i]->dump();
}
for (unsigned i = 0; i < DAG->SUnits.size(); i++) {
const SUnit &S = DAG->SUnits[i];
if (!S.isScheduled)
S.dump(DAG);
}
}
);
return SU;
}
void R600SchedStrategy::schedNode(SUnit *SU, bool IsTopNode) {
DEBUG(dbgs() << "scheduled: ");
DEBUG(SU->dump(DAG));
if (NextInstKind != CurInstKind) {
DEBUG(dbgs() << "Instruction Type Switch\n");
if (NextInstKind != IDAlu)
OccupedSlotsMask = 15;
CurEmitted = 0;
CurInstKind = NextInstKind;
}
if (CurInstKind == IDAlu) {
switch (getAluKind(SU)) {
case AluT_XYZW:
CurEmitted += 4;
break;
case AluDiscarded:
break;
default: {
++CurEmitted;
for (MachineInstr::mop_iterator It = SU->getInstr()->operands_begin(),
E = SU->getInstr()->operands_end(); It != E; ++It) {
MachineOperand &MO = *It;
if (MO.isReg() && MO.getReg() == AMDGPU::ALU_LITERAL_X)
++CurEmitted;
}
}
}
} else {
++CurEmitted;
}
DEBUG(dbgs() << CurEmitted << " Instructions Emitted in this clause\n");
if (CurInstKind != IDFetch) {
MoveUnits(Pending[IDFetch], Available[IDFetch]);
}
MoveUnits(Pending[IDOther], Available[IDOther]);
}
void R600SchedStrategy::releaseTopNode(SUnit *SU) {
int IK = getInstKind(SU);
DEBUG(dbgs() << IK << " <= ");
DEBUG(SU->dump(DAG));
Pending[IK]->push(SU);
}
void R600SchedStrategy::releaseBottomNode(SUnit *SU) {
}
bool R600SchedStrategy::regBelongsToClass(unsigned Reg,
const TargetRegisterClass *RC) const {
if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
return RC->contains(Reg);
} else {
return MRI->getRegClass(Reg) == RC;
}
}
R600SchedStrategy::AluKind R600SchedStrategy::getAluKind(SUnit *SU) const {
MachineInstr *MI = SU->getInstr();
switch (MI->getOpcode()) {
case AMDGPU::INTERP_PAIR_XY:
case AMDGPU::INTERP_PAIR_ZW:
case AMDGPU::INTERP_VEC_LOAD:
return AluT_XYZW;
case AMDGPU::COPY:
if (TargetRegisterInfo::isPhysicalRegister(MI->getOperand(1).getReg())) {
// %vregX = COPY Tn_X is likely to be discarded in favor of an
// assignement of Tn_X to %vregX, don't considers it in scheduling
return AluDiscarded;
}
else if (MI->getOperand(1).isUndef()) {
// MI will become a KILL, don't considers it in scheduling
return AluDiscarded;
}
default:
break;
}
// Does the instruction take a whole IG ?
if(TII->isVector(*MI) ||
TII->isCubeOp(MI->getOpcode()) ||
TII->isReductionOp(MI->getOpcode()))
return AluT_XYZW;
// Is the result already assigned to a channel ?
unsigned DestSubReg = MI->getOperand(0).getSubReg();
switch (DestSubReg) {
case AMDGPU::sub0:
return AluT_X;
case AMDGPU::sub1:
return AluT_Y;
case AMDGPU::sub2:
return AluT_Z;
case AMDGPU::sub3:
return AluT_W;
default:
break;
}
// Is the result already member of a X/Y/Z/W class ?
unsigned DestReg = MI->getOperand(0).getReg();
if (regBelongsToClass(DestReg, &AMDGPU::R600_TReg32_XRegClass) ||
regBelongsToClass(DestReg, &AMDGPU::R600_AddrRegClass))
return AluT_X;
if (regBelongsToClass(DestReg, &AMDGPU::R600_TReg32_YRegClass))
return AluT_Y;
if (regBelongsToClass(DestReg, &AMDGPU::R600_TReg32_ZRegClass))
return AluT_Z;
if (regBelongsToClass(DestReg, &AMDGPU::R600_TReg32_WRegClass))
return AluT_W;
if (regBelongsToClass(DestReg, &AMDGPU::R600_Reg128RegClass))
return AluT_XYZW;
return AluAny;
}
int R600SchedStrategy::getInstKind(SUnit* SU) {
int Opcode = SU->getInstr()->getOpcode();
if (TII->isALUInstr(Opcode)) {
return IDAlu;
}
switch (Opcode) {
case AMDGPU::COPY:
case AMDGPU::CONST_COPY:
case AMDGPU::INTERP_PAIR_XY:
case AMDGPU::INTERP_PAIR_ZW:
case AMDGPU::INTERP_VEC_LOAD:
case AMDGPU::DOT4_eg_pseudo:
case AMDGPU::DOT4_r600_pseudo:
return IDAlu;
case AMDGPU::TEX_VTX_CONSTBUF:
case AMDGPU::TEX_VTX_TEXBUF:
case AMDGPU::TEX_LD:
case AMDGPU::TEX_GET_TEXTURE_RESINFO:
case AMDGPU::TEX_GET_GRADIENTS_H:
case AMDGPU::TEX_GET_GRADIENTS_V:
case AMDGPU::TEX_SET_GRADIENTS_H:
case AMDGPU::TEX_SET_GRADIENTS_V:
case AMDGPU::TEX_SAMPLE:
case AMDGPU::TEX_SAMPLE_C:
case AMDGPU::TEX_SAMPLE_L:
case AMDGPU::TEX_SAMPLE_C_L:
case AMDGPU::TEX_SAMPLE_LB:
case AMDGPU::TEX_SAMPLE_C_LB:
case AMDGPU::TEX_SAMPLE_G:
case AMDGPU::TEX_SAMPLE_C_G:
case AMDGPU::TXD:
case AMDGPU::TXD_SHADOW:
return IDFetch;
default:
DEBUG(
dbgs() << "other inst: ";
SU->dump(DAG);
);
return IDOther;
}
}
class ConstPairs {
private:
unsigned XYPair;
unsigned ZWPair;
public:
ConstPairs(unsigned ReadConst[3]) : XYPair(0), ZWPair(0) {
for (unsigned i = 0; i < 3; i++) {
unsigned ReadConstChan = ReadConst[i] & 3;
unsigned ReadConstIndex = ReadConst[i] & (~3);
if (ReadConstChan < 2) {
if (!XYPair) {
XYPair = ReadConstIndex;
}
} else {
if (!ZWPair) {
ZWPair = ReadConstIndex;
}
}
}
}
bool isCompatibleWith(const ConstPairs& CP) const {
return (!XYPair || !CP.XYPair || CP.XYPair == XYPair) &&
(!ZWPair || !CP.ZWPair || CP.ZWPair == ZWPair);
}
};
static
const ConstPairs getPairs(const R600InstrInfo *TII, const MachineInstr& MI) {
unsigned ReadConsts[3] = {0, 0, 0};
R600Operands::Ops OpTable[3][2] = {
{R600Operands::SRC0, R600Operands::SRC0_SEL},
{R600Operands::SRC1, R600Operands::SRC1_SEL},
{R600Operands::SRC2, R600Operands::SRC2_SEL},
};
if (!TII->isALUInstr(MI.getOpcode()))
return ConstPairs(ReadConsts);
for (unsigned i = 0; i < 3; i++) {
int SrcIdx = TII->getOperandIdx(MI.getOpcode(), OpTable[i][0]);
if (SrcIdx < 0)
break;
if (MI.getOperand(SrcIdx).getReg() == AMDGPU::ALU_CONST)
ReadConsts[i] =MI.getOperand(
TII->getOperandIdx(MI.getOpcode(), OpTable[i][1])).getImm();
}
return ConstPairs(ReadConsts);
}
bool
R600SchedStrategy::isBundleable(const MachineInstr& MI) {
const ConstPairs &MIPair = getPairs(TII, MI);
for (unsigned i = 0; i < 4; i++) {
if (!InstructionsGroupCandidate[i])
continue;
const ConstPairs &IGPair = getPairs(TII,
*InstructionsGroupCandidate[i]->getInstr());
if (!IGPair.isCompatibleWith(MIPair))
return false;
}
return true;
}
SUnit *R600SchedStrategy::PopInst(std::multiset<SUnit *, CompareSUnit> &Q) {
if (Q.empty())
return NULL;
for (std::set<SUnit *, CompareSUnit>::iterator It = Q.begin(), E = Q.end();
It != E; ++It) {
SUnit *SU = *It;
if (isBundleable(*SU->getInstr())) {
Q.erase(It);
return SU;
}
}
return NULL;
}
void R600SchedStrategy::LoadAlu() {
ReadyQueue *QSrc = Pending[IDAlu];
for (ReadyQueue::iterator I = QSrc->begin(),
E = QSrc->end(); I != E; ++I) {
(*I)->NodeQueueId &= ~QSrc->getID();
AluKind AK = getAluKind(*I);
AvailableAlus[AK].insert(*I);
}
QSrc->clear();
}
void R600SchedStrategy::PrepareNextSlot() {
DEBUG(dbgs() << "New Slot\n");
assert (OccupedSlotsMask && "Slot wasn't filled");
OccupedSlotsMask = 0;
memset(InstructionsGroupCandidate, 0, sizeof(InstructionsGroupCandidate));
LoadAlu();
}
void R600SchedStrategy::AssignSlot(MachineInstr* MI, unsigned Slot) {
unsigned DestReg = MI->getOperand(0).getReg();
// PressureRegister crashes if an operand is def and used in the same inst
// and we try to constraint its regclass
for (MachineInstr::mop_iterator It = MI->operands_begin(),
E = MI->operands_end(); It != E; ++It) {
MachineOperand &MO = *It;
if (MO.isReg() && !MO.isDef() &&
MO.getReg() == MI->getOperand(0).getReg())
return;
}
// Constrains the regclass of DestReg to assign it to Slot
switch (Slot) {
case 0:
MRI->constrainRegClass(DestReg, &AMDGPU::R600_TReg32_XRegClass);
break;
case 1:
MRI->constrainRegClass(DestReg, &AMDGPU::R600_TReg32_YRegClass);
break;
case 2:
MRI->constrainRegClass(DestReg, &AMDGPU::R600_TReg32_ZRegClass);
break;
case 3:
MRI->constrainRegClass(DestReg, &AMDGPU::R600_TReg32_WRegClass);
break;
}
}
SUnit *R600SchedStrategy::AttemptFillSlot(unsigned Slot) {
static const AluKind IndexToID[] = {AluT_X, AluT_Y, AluT_Z, AluT_W};
SUnit *SlotedSU = PopInst(AvailableAlus[IndexToID[Slot]]);
SUnit *UnslotedSU = PopInst(AvailableAlus[AluAny]);
if (!UnslotedSU) {
return SlotedSU;
} else if (!SlotedSU) {
AssignSlot(UnslotedSU->getInstr(), Slot);
return UnslotedSU;
} else {
//Determine which one to pick (the lesser one)
if (CompareSUnit()(SlotedSU, UnslotedSU)) {
AvailableAlus[AluAny].insert(UnslotedSU);
return SlotedSU;
} else {
AvailableAlus[IndexToID[Slot]].insert(SlotedSU);
AssignSlot(UnslotedSU->getInstr(), Slot);
return UnslotedSU;
}
}
}
bool R600SchedStrategy::isAvailablesAluEmpty() const {
return Pending[IDAlu]->empty() && AvailableAlus[AluAny].empty() &&
AvailableAlus[AluT_XYZW].empty() && AvailableAlus[AluT_X].empty() &&
AvailableAlus[AluT_Y].empty() && AvailableAlus[AluT_Z].empty() &&
AvailableAlus[AluT_W].empty() && AvailableAlus[AluDiscarded].empty();
}
SUnit* R600SchedStrategy::pickAlu() {
while (!isAvailablesAluEmpty()) {
if (!OccupedSlotsMask) {
// Flush physical reg copies (RA will discard them)
if (!AvailableAlus[AluDiscarded].empty()) {
OccupedSlotsMask = 15;
return PopInst(AvailableAlus[AluDiscarded]);
}
// If there is a T_XYZW alu available, use it
if (!AvailableAlus[AluT_XYZW].empty()) {
OccupedSlotsMask = 15;
return PopInst(AvailableAlus[AluT_XYZW]);
}
}
for (unsigned Chan = 0; Chan < 4; ++Chan) {
bool isOccupied = OccupedSlotsMask & (1 << Chan);
if (!isOccupied) {
SUnit *SU = AttemptFillSlot(Chan);
if (SU) {
OccupedSlotsMask |= (1 << Chan);
InstructionsGroupCandidate[Chan] = SU;
return SU;
}
}
}
PrepareNextSlot();
}
return NULL;
}
SUnit* R600SchedStrategy::pickOther(int QID) {
SUnit *SU = 0;
ReadyQueue *AQ = Available[QID];
if (AQ->empty()) {
MoveUnits(Pending[QID], AQ);
}
if (!AQ->empty()) {
SU = *AQ->begin();
AQ->remove(AQ->begin());
}
return SU;
}