//
/// \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/CodeGen/MachineRegisterInfo.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
void R600SchedStrategy::initialize(ScheduleDAGMI *dag) {
-
- DAG = dag;
+ assert(dag->hasVRegLiveness() && "R600SchedStrategy needs vreg liveness");
+ DAG = static_cast<ScheduleDAGMILive*>(dag);
TII = static_cast<const R600InstrInfo*>(DAG->TII);
TRI = static_cast<const R600RegisterInfo*>(DAG->TRI);
+ VLIW5 = !DAG->MF.getTarget().getSubtarget<AMDGPUSubtarget>().hasCaymanISA();
MRI = &DAG->MRI;
CurInstKind = IDOther;
CurEmitted = 0;
- OccupedSlotsMask = 15;
+ OccupedSlotsMask = 31;
InstKindLimit[IDAlu] = TII->getMaxAlusPerClause();
-
+ InstKindLimit[IDOther] = 32;
const AMDGPUSubtarget &ST = DAG->TM.getSubtarget<AMDGPUSubtarget>();
InstKindLimit[IDFetch] = ST.getTexVTXClauseSize();
+ AluInstCount = 0;
+ FetchInstCount = 0;
}
void R600SchedStrategy::MoveUnits(std::vector<SUnit *> &QSrc,
QSrc.clear();
}
+static
+unsigned getWFCountLimitedByGPR(unsigned GPRCount) {
+ assert (GPRCount && "GPRCount cannot be 0");
+ return 248 / GPRCount;
+}
+
SUnit* R600SchedStrategy::pickNode(bool &IsTopNode) {
SUnit *SU = 0;
- IsTopNode = true;
NextInstKind = IDOther;
+ IsTopNode = false;
+
// check if we might want to switch current clause type
- bool AllowSwitchToAlu = (CurInstKind == IDOther) ||
- (CurEmitted >= InstKindLimit[CurInstKind]) ||
+ bool AllowSwitchToAlu = (CurEmitted >= InstKindLimit[CurInstKind]) ||
(Available[CurInstKind].empty());
bool AllowSwitchFromAlu = (CurEmitted >= InstKindLimit[CurInstKind]) &&
(!Available[IDFetch].empty() || !Available[IDOther].empty());
- if ((AllowSwitchToAlu && CurInstKind != IDAlu) ||
- (!AllowSwitchFromAlu && CurInstKind == IDAlu)) {
+ if (CurInstKind == IDAlu && !Available[IDFetch].empty()) {
+ // We use the heuristic provided by AMD Accelerated Parallel Processing
+ // OpenCL Programming Guide :
+ // The approx. number of WF that allows TEX inst to hide ALU inst is :
+ // 500 (cycles for TEX) / (AluFetchRatio * 8 (cycles for ALU))
+ float ALUFetchRationEstimate =
+ (AluInstCount + AvailablesAluCount() + Pending[IDAlu].size()) /
+ (FetchInstCount + Available[IDFetch].size());
+ unsigned NeededWF = 62.5f / ALUFetchRationEstimate;
+ DEBUG( dbgs() << NeededWF << " approx. Wavefronts Required\n" );
+ // We assume the local GPR requirements to be "dominated" by the requirement
+ // of the TEX clause (which consumes 128 bits regs) ; ALU inst before and
+ // after TEX are indeed likely to consume or generate values from/for the
+ // TEX clause.
+ // Available[IDFetch].size() * 2 : GPRs required in the Fetch clause
+ // We assume that fetch instructions are either TnXYZW = TEX TnXYZW (need
+ // one GPR) or TmXYZW = TnXYZW (need 2 GPR).
+ // (TODO : use RegisterPressure)
+ // If we are going too use too many GPR, we flush Fetch instruction to lower
+ // register pressure on 128 bits regs.
+ unsigned NearRegisterRequirement = 2 * Available[IDFetch].size();
+ if (NeededWF > getWFCountLimitedByGPR(NearRegisterRequirement))
+ AllowSwitchFromAlu = true;
+ }
+
+ if (!SU && ((AllowSwitchToAlu && CurInstKind != IDAlu) ||
+ (!AllowSwitchFromAlu && CurInstKind == IDAlu))) {
// try to pick ALU
SU = pickAlu();
+ if (!SU && !PhysicalRegCopy.empty()) {
+ SU = PhysicalRegCopy.front();
+ PhysicalRegCopy.erase(PhysicalRegCopy.begin());
+ }
if (SU) {
if (CurEmitted >= InstKindLimit[IDAlu])
CurEmitted = 0;
DEBUG(
if (SU) {
- dbgs() << "picked node: ";
+ dbgs() << " ** Pick node **\n";
SU->dump(DAG);
} else {
- dbgs() << "NO NODE ";
+ dbgs() << "NO NODE \n";
for (unsigned i = 0; i < DAG->SUnits.size(); i++) {
const SUnit &S = DAG->SUnits[i];
if (!S.isScheduled)
}
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;
+ OccupedSlotsMask |= 31;
CurEmitted = 0;
CurInstKind = NextInstKind;
}
if (CurInstKind == IDAlu) {
+ AluInstCount ++;
switch (getAluKind(SU)) {
case AluT_XYZW:
CurEmitted += 4;
if (CurInstKind != IDFetch) {
MoveUnits(Pending[IDFetch], Available[IDFetch]);
- }
- MoveUnits(Pending[IDOther], Available[IDOther]);
+ } else
+ FetchInstCount++;
}
-void R600SchedStrategy::releaseTopNode(SUnit *SU) {
- int IK = getInstKind(SU);
+static bool
+isPhysicalRegCopy(MachineInstr *MI) {
+ if (MI->getOpcode() != AMDGPU::COPY)
+ return false;
- DEBUG(dbgs() << IK << " <= ");
- DEBUG(SU->dump(DAG));
+ return !TargetRegisterInfo::isVirtualRegister(MI->getOperand(1).getReg());
+}
- Pending[IK].push_back(SU);
+void R600SchedStrategy::releaseTopNode(SUnit *SU) {
+ DEBUG(dbgs() << "Top Releasing ";SU->dump(DAG););
}
void R600SchedStrategy::releaseBottomNode(SUnit *SU) {
+ DEBUG(dbgs() << "Bottom Releasing ";SU->dump(DAG););
+ if (isPhysicalRegCopy(SU->getInstr())) {
+ PhysicalRegCopy.push_back(SU);
+ return;
+ }
+
+ int IK = getInstKind(SU);
+
+ // There is no export clause, we can schedule one as soon as its ready
+ if (IK == IDOther)
+ Available[IDOther].push_back(SU);
+ else
+ Pending[IK].push_back(SU);
+
}
bool R600SchedStrategy::regBelongsToClass(unsigned Reg,
R600SchedStrategy::AluKind R600SchedStrategy::getAluKind(SUnit *SU) const {
MachineInstr *MI = SU->getInstr();
+ if (TII->isTransOnly(MI))
+ return AluTrans;
+
switch (MI->getOpcode()) {
+ case AMDGPU::PRED_X:
+ return AluPredX;
case AMDGPU::INTERP_PAIR_XY:
case AMDGPU::INTERP_PAIR_ZW:
case AMDGPU::INTERP_VEC_LOAD:
case AMDGPU::DOT_4:
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()) {
+ if (MI->getOperand(1).isUndef()) {
// MI will become a KILL, don't considers it in scheduling
return AluDiscarded;
}
}
// Does the instruction take a whole IG ?
+ // XXX: Is it possible to add a helper function in R600InstrInfo that can
+ // be used here and in R600PacketizerList::isSoloInstruction() ?
if(TII->isVector(*MI) ||
TII->isCubeOp(MI->getOpcode()) ||
- TII->isReductionOp(MI->getOpcode()))
+ TII->isReductionOp(MI->getOpcode()) ||
+ MI->getOpcode() == AMDGPU::GROUP_BARRIER) {
return AluT_XYZW;
+ }
+
+ if (TII->isLDSInstr(MI->getOpcode())) {
+ return AluT_X;
+ }
// Is the result already assigned to a channel ?
unsigned DestSubReg = MI->getOperand(0).getSubReg();
if (regBelongsToClass(DestReg, &AMDGPU::R600_Reg128RegClass))
return AluT_XYZW;
+ // LDS src registers cannot be used in the Trans slot.
+ if (TII->readsLDSSrcReg(MI))
+ return AluT_XYZW;
+
return AluAny;
}
}
switch (Opcode) {
+ case AMDGPU::PRED_X:
case AMDGPU::COPY:
case AMDGPU::CONST_COPY:
case AMDGPU::INTERP_PAIR_XY:
}
}
-SUnit *R600SchedStrategy::PopInst(std::vector<SUnit *> &Q) {
+SUnit *R600SchedStrategy::PopInst(std::vector<SUnit *> &Q, bool AnyALU) {
if (Q.empty())
return NULL;
for (std::vector<SUnit *>::reverse_iterator It = Q.rbegin(), E = Q.rend();
It != E; ++It) {
SUnit *SU = *It;
InstructionsGroupCandidate.push_back(SU->getInstr());
- if (TII->canBundle(InstructionsGroupCandidate)) {
+ if (TII->fitsConstReadLimitations(InstructionsGroupCandidate)
+ && (!AnyALU || !TII->isVectorOnly(SU->getInstr()))
+ ) {
InstructionsGroupCandidate.pop_back();
Q.erase((It + 1).base());
return SU;
DEBUG(dbgs() << "New Slot\n");
assert (OccupedSlotsMask && "Slot wasn't filled");
OccupedSlotsMask = 0;
+// if (HwGen == AMDGPUSubtarget::NORTHERN_ISLANDS)
+// OccupedSlotsMask |= 16;
InstructionsGroupCandidate.clear();
LoadAlu();
}
void R600SchedStrategy::AssignSlot(MachineInstr* MI, unsigned Slot) {
- unsigned DestReg = MI->getOperand(0).getReg();
+ int DstIndex = TII->getOperandIdx(MI->getOpcode(), AMDGPU::OpName::dst);
+ if (DstIndex == -1) {
+ return;
+ }
+ unsigned DestReg = MI->getOperand(DstIndex).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())
+ MO.getReg() == DestReg)
return;
}
// Constrains the regclass of DestReg to assign it to Slot
}
}
-SUnit *R600SchedStrategy::AttemptFillSlot(unsigned Slot) {
+SUnit *R600SchedStrategy::AttemptFillSlot(unsigned Slot, bool AnyAlu) {
static const AluKind IndexToID[] = {AluT_X, AluT_Y, AluT_Z, AluT_W};
- SUnit *SlotedSU = PopInst(AvailableAlus[IndexToID[Slot]]);
+ SUnit *SlotedSU = PopInst(AvailableAlus[IndexToID[Slot]], AnyAlu);
if (SlotedSU)
return SlotedSU;
- SUnit *UnslotedSU = PopInst(AvailableAlus[AluAny]);
+ SUnit *UnslotedSU = PopInst(AvailableAlus[AluAny], AnyAlu);
if (UnslotedSU)
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();
+unsigned R600SchedStrategy::AvailablesAluCount() const {
+ return AvailableAlus[AluAny].size() + AvailableAlus[AluT_XYZW].size() +
+ AvailableAlus[AluT_X].size() + AvailableAlus[AluT_Y].size() +
+ AvailableAlus[AluT_Z].size() + AvailableAlus[AluT_W].size() +
+ AvailableAlus[AluTrans].size() + AvailableAlus[AluDiscarded].size() +
+ AvailableAlus[AluPredX].size();
}
SUnit* R600SchedStrategy::pickAlu() {
- while (!isAvailablesAluEmpty()) {
+ while (AvailablesAluCount() || !Pending[IDAlu].empty()) {
if (!OccupedSlotsMask) {
+ // Bottom up scheduling : predX must comes first
+ if (!AvailableAlus[AluPredX].empty()) {
+ OccupedSlotsMask |= 31;
+ return PopInst(AvailableAlus[AluPredX], false);
+ }
// Flush physical reg copies (RA will discard them)
if (!AvailableAlus[AluDiscarded].empty()) {
- OccupedSlotsMask = 15;
- return PopInst(AvailableAlus[AluDiscarded]);
+ OccupedSlotsMask |= 31;
+ return PopInst(AvailableAlus[AluDiscarded], false);
}
// If there is a T_XYZW alu available, use it
if (!AvailableAlus[AluT_XYZW].empty()) {
- OccupedSlotsMask = 15;
- return PopInst(AvailableAlus[AluT_XYZW]);
+ OccupedSlotsMask |= 15;
+ return PopInst(AvailableAlus[AluT_XYZW], false);
}
}
- for (unsigned Chan = 0; Chan < 4; ++Chan) {
+ bool TransSlotOccuped = OccupedSlotsMask & 16;
+ if (!TransSlotOccuped && VLIW5) {
+ if (!AvailableAlus[AluTrans].empty()) {
+ OccupedSlotsMask |= 16;
+ return PopInst(AvailableAlus[AluTrans], false);
+ }
+ SUnit *SU = AttemptFillSlot(3, true);
+ if (SU) {
+ OccupedSlotsMask |= 16;
+ return SU;
+ }
+ }
+ for (int Chan = 3; Chan > -1; --Chan) {
bool isOccupied = OccupedSlotsMask & (1 << Chan);
if (!isOccupied) {
- SUnit *SU = AttemptFillSlot(Chan);
+ SUnit *SU = AttemptFillSlot(Chan, false);
if (SU) {
OccupedSlotsMask |= (1 << Chan);
InstructionsGroupCandidate.push_back(SU->getInstr());
}
return SU;
}
-
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