#include "ScheduleDAGInstrs.h"
#include "llvm/Operator.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
+#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetSubtarget.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallSet.h"
const MachineDominatorTree &mdt)
: ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()),
InstrItins(mf.getTarget().getInstrItineraryData()),
- Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT) {
- DbgValueVec.clear();
+ Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()),
+ LoopRegs(MLI, MDT), FirstDbgValue(0) {
+ DbgValues.clear();
}
/// Run - perform scheduling.
} while (1);
}
-/// getUnderlyingObject - This is a wrapper around Value::getUnderlyingObject
+/// getUnderlyingObject - This is a wrapper around GetUnderlyingObject
/// and adds support for basic ptrtoint+arithmetic+inttoptr sequences.
static const Value *getUnderlyingObject(const Value *V) {
// First just call Value::getUnderlyingObject to let it do what it does.
do {
- V = V->getUnderlyingObject();
+ V = GetUnderlyingObject(V);
// If it found an inttoptr, use special code to continue climing.
if (Operator::getOpcode(V) != Instruction::IntToPtr)
break;
// such aliases.
if (PSV->isAliased(MFI))
return 0;
-
+
MayAlias = PSV->mayAlias(MFI);
return V;
}
}
}
+/// AddSchedBarrierDeps - Add dependencies from instructions in the current
+/// list of instructions being scheduled to scheduling barrier by adding
+/// the exit SU to the register defs and use list. This is because we want to
+/// make sure instructions which define registers that are either used by
+/// the terminator or are live-out are properly scheduled. This is
+/// especially important when the definition latency of the return value(s)
+/// are too high to be hidden by the branch or when the liveout registers
+/// used by instructions in the fallthrough block.
+void ScheduleDAGInstrs::AddSchedBarrierDeps() {
+ MachineInstr *ExitMI = InsertPos != BB->end() ? &*InsertPos : 0;
+ ExitSU.setInstr(ExitMI);
+ bool AllDepKnown = ExitMI &&
+ (ExitMI->getDesc().isCall() || ExitMI->getDesc().isBarrier());
+ if (ExitMI && AllDepKnown) {
+ // If it's a call or a barrier, add dependencies on the defs and uses of
+ // instruction.
+ for (unsigned i = 0, e = ExitMI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = ExitMI->getOperand(i);
+ if (!MO.isReg() || MO.isDef()) continue;
+ unsigned Reg = MO.getReg();
+ if (Reg == 0) continue;
+
+ assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!");
+ Uses[Reg].push_back(&ExitSU);
+ }
+ } else {
+ // For others, e.g. fallthrough, conditional branch, assume the exit
+ // uses all the registers that are livein to the successor blocks.
+ SmallSet<unsigned, 8> Seen;
+ for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
+ SE = BB->succ_end(); SI != SE; ++SI)
+ for (MachineBasicBlock::livein_iterator I = (*SI)->livein_begin(),
+ E = (*SI)->livein_end(); I != E; ++I) {
+ unsigned Reg = *I;
+ if (Seen.insert(Reg))
+ Uses[Reg].push_back(&ExitSU);
+ }
+ }
+}
+
void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
// We'll be allocating one SUnit for each instruction, plus one for
// the region exit node.
std::map<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs;
std::map<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses;
- // Keep track of dangling debug references to registers.
- std::vector<std::pair<MachineInstr*, unsigned> >
- DanglingDebugValue(TRI->getNumRegs(),
- std::make_pair(static_cast<MachineInstr*>(0), 0));
-
// Check to see if the scheduler cares about latencies.
bool UnitLatencies = ForceUnitLatencies();
// Ask the target if address-backscheduling is desirable, and if so how much.
- const TargetSubtarget &ST = TM.getSubtarget<TargetSubtarget>();
+ const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();
unsigned SpecialAddressLatency = ST.getSpecialAddressLatency();
// Remove any stale debug info; sometimes BuildSchedGraph is called again
// without emitting the info from the previous call.
- DbgValueVec.clear();
+ DbgValues.clear();
+ FirstDbgValue = NULL;
+
+ // Model data dependencies between instructions being scheduled and the
+ // ExitSU.
+ AddSchedBarrierDeps();
+
+ for (int i = 0, e = TRI->getNumRegs(); i != e; ++i) {
+ assert(Defs[i].empty() && "Only BuildGraph should push/pop Defs");
+ }
// Walk the list of instructions, from bottom moving up.
+ MachineInstr *PrevMI = NULL;
for (MachineBasicBlock::iterator MII = InsertPos, MIE = Begin;
MII != MIE; --MII) {
MachineInstr *MI = prior(MII);
- // DBG_VALUE does not have SUnit's built, so just remember these for later
- // reinsertion.
+ if (MI && PrevMI) {
+ DbgValues.push_back(std::make_pair(PrevMI, MI));
+ PrevMI = NULL;
+ }
+
if (MI->isDebugValue()) {
- if (MI->getNumOperands()==3 && MI->getOperand(0).isReg() &&
- MI->getOperand(0).getReg())
- DanglingDebugValue[MI->getOperand(0).getReg()] =
- std::make_pair(MI, DbgValueVec.size());
- DbgValueVec.push_back(MI);
+ PrevMI = MI;
continue;
}
- const TargetInstrDesc &TID = MI->getDesc();
- assert(!TID.isTerminator() && !MI->isLabel() &&
+
+ const MCInstrDesc &MCID = MI->getDesc();
+ assert(!MCID.isTerminator() && !MI->isLabel() &&
"Cannot schedule terminators or labels!");
// Create the SUnit for this MI.
SUnit *SU = NewSUnit(MI);
+ SU->isCall = MCID.isCall();
+ SU->isCommutable = MCID.isCommutable();
// Assign the Latency field of SU using target-provided information.
if (UnitLatencies)
assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!");
- if (MO.isDef() && DanglingDebugValue[Reg].first!=0) {
- SU->DbgInstrList.push_back(DanglingDebugValue[Reg].first);
- DbgValueVec[DanglingDebugValue[Reg].second] = 0;
- DanglingDebugValue[Reg] = std::make_pair((MachineInstr*)0, 0);
- }
-
std::vector<SUnit *> &UseList = Uses[Reg];
+ // Defs are push in the order they are visited and never reordered.
std::vector<SUnit *> &DefList = Defs[Reg];
// Optionally add output and anti dependencies. For anti
// dependencies we use a latency of 0 because for a multi-issue
unsigned AOLatency = (Kind == SDep::Anti) ? 0 : 1;
for (unsigned i = 0, e = DefList.size(); i != e; ++i) {
SUnit *DefSU = DefList[i];
+ if (DefSU == &ExitSU)
+ continue;
if (DefSU != SU &&
(Kind != SDep::Output || !MO.isDead() ||
!DefSU->getInstr()->registerDefIsDead(Reg)))
DefSU->addPred(SDep(SU, Kind, AOLatency, /*Reg=*/Reg));
}
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- std::vector<SUnit *> &DefList = Defs[*Alias];
- for (unsigned i = 0, e = DefList.size(); i != e; ++i) {
- SUnit *DefSU = DefList[i];
+ std::vector<SUnit *> &MemDefList = Defs[*Alias];
+ for (unsigned i = 0, e = MemDefList.size(); i != e; ++i) {
+ SUnit *DefSU = MemDefList[i];
+ if (DefSU == &ExitSU)
+ continue;
if (DefSU != SU &&
(Kind != SDep::Output || !MO.isDead() ||
!DefSU->getInstr()->registerDefIsDead(*Alias)))
// TODO: Perhaps we should get rid of
// SpecialAddressLatency and just move this into
// adjustSchedDependency for the targets that care about it.
- if (SpecialAddressLatency != 0 && !UnitLatencies) {
+ if (SpecialAddressLatency != 0 && !UnitLatencies &&
+ UseSU != &ExitSU) {
MachineInstr *UseMI = UseSU->getInstr();
- const TargetInstrDesc &UseTID = UseMI->getDesc();
+ const MCInstrDesc &UseMCID = UseMI->getDesc();
int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg);
assert(RegUseIndex >= 0 && "UseMI doesn's use register!");
- if ((UseTID.mayLoad() || UseTID.mayStore()) &&
- (unsigned)RegUseIndex < UseTID.getNumOperands() &&
- UseTID.OpInfo[RegUseIndex].isLookupPtrRegClass())
+ if (RegUseIndex >= 0 &&
+ (UseMCID.mayLoad() || UseMCID.mayStore()) &&
+ (unsigned)RegUseIndex < UseMCID.getNumOperands() &&
+ UseMCID.OpInfo[RegUseIndex].isLookupPtrRegClass())
LDataLatency += SpecialAddressLatency;
}
// Adjust the dependence latency using operand def/use
unsigned Count = I->second.second;
const MachineInstr *UseMI = UseMO->getParent();
unsigned UseMOIdx = UseMO - &UseMI->getOperand(0);
- const TargetInstrDesc &UseTID = UseMI->getDesc();
+ const MCInstrDesc &UseMCID = UseMI->getDesc();
// TODO: If we knew the total depth of the region here, we could
// handle the case where the whole loop is inside the region but
// is large enough that the isScheduleHigh trick isn't needed.
- if (UseMOIdx < UseTID.getNumOperands()) {
+ if (UseMOIdx < UseMCID.getNumOperands()) {
// Currently, we only support scheduling regions consisting of
// single basic blocks. Check to see if the instruction is in
// the same region by checking to see if it has the same parent.
if (UseMI->getParent() != MI->getParent()) {
unsigned Latency = SU->Latency;
- if (UseTID.OpInfo[UseMOIdx].isLookupPtrRegClass())
+ if (UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass())
Latency += SpecialAddressLatency;
// This is a wild guess as to the portion of the latency which
// will be overlapped by work done outside the current
// scheduling region.
Latency -= std::min(Latency, Count);
- // Add the artifical edge.
+ // Add the artificial edge.
ExitSU.addPred(SDep(SU, SDep::Order, Latency,
/*Reg=*/0, /*isNormalMemory=*/false,
/*isMustAlias=*/false,
/*isArtificial=*/true));
} else if (SpecialAddressLatency > 0 &&
- UseTID.OpInfo[UseMOIdx].isLookupPtrRegClass()) {
+ UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass()) {
// The entire loop body is within the current scheduling region
// and the latency of this operation is assumed to be greater
// than the latency of the loop.
UseList.clear();
if (!MO.isDead())
DefList.clear();
+
+ // Calls will not be reordered because of chain dependencies (see
+ // below). Since call operands are dead, calls may continue to be added
+ // to the DefList making dependence checking quadratic in the size of
+ // the block. Instead, we leave only one call at the back of the
+ // DefList.
+ if (SU->isCall) {
+ while (!DefList.empty() && DefList.back()->isCall)
+ DefList.pop_back();
+ }
DefList.push_back(SU);
} else {
UseList.push_back(SU);
// produce more precise dependence information.
#define STORE_LOAD_LATENCY 1
unsigned TrueMemOrderLatency = 0;
- if (TID.isCall() || TID.hasUnmodeledSideEffects() ||
- (MI->hasVolatileMemoryRef() &&
- (!TID.mayLoad() || !MI->isInvariantLoad(AA)))) {
+ if (MCID.isCall() || MI->hasUnmodeledSideEffects() ||
+ (MI->hasVolatileMemoryRef() &&
+ (!MCID.mayLoad() || !MI->isInvariantLoad(AA)))) {
// Be conservative with these and add dependencies on all memory
// references, even those that are known to not alias.
- for (std::map<const Value *, SUnit *>::iterator I =
+ for (std::map<const Value *, SUnit *>::iterator I =
NonAliasMemDefs.begin(), E = NonAliasMemDefs.end(); I != E; ++I) {
I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
}
PendingLoads.clear();
AliasMemDefs.clear();
AliasMemUses.clear();
- } else if (TID.mayStore()) {
+ } else if (MCID.mayStore()) {
bool MayAlias = true;
TrueMemOrderLatency = STORE_LOAD_LATENCY;
if (const Value *V = getUnderlyingObjectForInstr(MI, MFI, MayAlias)) {
// A store to a specific PseudoSourceValue. Add precise dependencies.
// Record the def in MemDefs, first adding a dep if there is
// an existing def.
- std::map<const Value *, SUnit *>::iterator I =
+ std::map<const Value *, SUnit *>::iterator I =
((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V));
- std::map<const Value *, SUnit *>::iterator IE =
+ std::map<const Value *, SUnit *>::iterator IE =
((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end());
if (I != IE) {
I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0, /*Reg=*/0,
// Treat all other stores conservatively.
goto new_alias_chain;
}
- } else if (TID.mayLoad()) {
+
+ if (!ExitSU.isPred(SU))
+ // Push store's up a bit to avoid them getting in between cmp
+ // and branches.
+ ExitSU.addPred(SDep(SU, SDep::Order, 0,
+ /*Reg=*/0, /*isNormalMemory=*/false,
+ /*isMustAlias=*/false,
+ /*isArtificial=*/true));
+ } else if (MCID.mayLoad()) {
bool MayAlias = true;
TrueMemOrderLatency = 0;
if (MI->isInvariantLoad(AA)) {
// Invariant load, no chain dependencies needed!
} else {
- if (const Value *V =
+ if (const Value *V =
getUnderlyingObjectForInstr(MI, MFI, MayAlias)) {
// A load from a specific PseudoSourceValue. Add precise dependencies.
- std::map<const Value *, SUnit *>::iterator I =
+ std::map<const Value *, SUnit *>::iterator I =
((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V));
- std::map<const Value *, SUnit *>::iterator IE =
+ std::map<const Value *, SUnit *>::iterator IE =
((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end());
if (I != IE)
I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0, /*Reg=*/0,
/*isNormalMemory=*/true));
if (MayAlias)
AliasMemUses[V].push_back(SU);
- else
+ else
NonAliasMemUses[V].push_back(SU);
} else {
// A load with no underlying object. Depend on all
// potentially aliasing stores.
- for (std::map<const Value *, SUnit *>::iterator I =
+ for (std::map<const Value *, SUnit *>::iterator I =
AliasMemDefs.begin(), E = AliasMemDefs.end(); I != E; ++I)
I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
-
+
PendingLoads.push_back(SU);
MayAlias = true;
}
-
+
// Add dependencies on alias and barrier chains, if needed.
if (MayAlias && AliasChain)
AliasChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
if (BarrierChain)
BarrierChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
- }
+ }
}
}
+ if (PrevMI)
+ FirstDbgValue = PrevMI;
for (int i = 0, e = TRI->getNumRegs(); i != e; ++i) {
Defs[i].clear();
// extra time.
if (SU->getInstr()->getDesc().mayLoad())
SU->Latency += 2;
- } else
- SU->Latency =
- InstrItins->getStageLatency(SU->getInstr()->getDesc().getSchedClass());
+ } else {
+ SU->Latency = TII->getInstrLatency(InstrItins, SU->getInstr());
+ }
}
-void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use,
+void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use,
SDep& dep) const {
if (!InstrItins || InstrItins->isEmpty())
return;
-
+
// For a data dependency with a known register...
if ((dep.getKind() != SDep::Data) || (dep.getReg() == 0))
return;
if (DefIdx != -1) {
const MachineOperand &MO = DefMI->getOperand(DefIdx);
if (MO.isReg() && MO.isImplicit() &&
- DefIdx >= DefMI->getDesc().getNumOperands()) {
+ DefIdx >= (int)DefMI->getDesc().getNumOperands()) {
// This is an implicit def, getOperandLatency() won't return the correct
// latency. e.g.
// %D6<def>, %D7<def> = VLD1q16 %R2<kill>, 0, ..., %Q3<imp-def>
MachineInstr *UseMI = Use->getInstr();
// For all uses of the register, calculate the maxmimum latency
int Latency = -1;
- for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = UseMI->getOperand(i);
- if (!MO.isReg() || !MO.isUse())
- continue;
- unsigned MOReg = MO.getReg();
- if (MOReg != Reg)
- continue;
-
- int UseCycle = TII->getOperandLatency(InstrItins, DefMI, DefIdx, UseMI, i);
- Latency = std::max(Latency, UseCycle);
-
- // If we found a latency, then replace the existing dependence latency.
- if (Latency >= 0)
- dep.setLatency(Latency);
+ if (UseMI) {
+ for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = UseMI->getOperand(i);
+ if (!MO.isReg() || !MO.isUse())
+ continue;
+ unsigned MOReg = MO.getReg();
+ if (MOReg != Reg)
+ continue;
+
+ int UseCycle = TII->getOperandLatency(InstrItins, DefMI, DefIdx,
+ UseMI, i);
+ Latency = std::max(Latency, UseCycle);
+ }
+ } else {
+ // UseMI is null, then it must be a scheduling barrier.
+ if (!InstrItins || InstrItins->isEmpty())
+ return;
+ unsigned DefClass = DefMI->getDesc().getSchedClass();
+ Latency = InstrItins->getOperandCycle(DefClass, DefIdx);
}
+
+ // If we found a latency, then replace the existing dependence latency.
+ if (Latency >= 0)
+ dep.setLatency(Latency);
}
}
BB->remove(I);
}
- // First reinsert any remaining debug_values; these are either constants,
- // or refer to live-in registers. The beginning of the block is the right
- // place for the latter. The former might reasonably be placed elsewhere
- // using some kind of ordering algorithm, but right now it doesn't matter.
- for (int i = DbgValueVec.size()-1; i>=0; --i)
- if (DbgValueVec[i])
- BB->insert(InsertPos, DbgValueVec[i]);
+ // If first instruction was a DBG_VALUE then put it back.
+ if (FirstDbgValue)
+ BB->insert(InsertPos, FirstDbgValue);
// Then re-insert them according to the given schedule.
for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
- SUnit *SU = Sequence[i];
- if (!SU) {
+ if (SUnit *SU = Sequence[i])
+ BB->insert(InsertPos, SU->getInstr());
+ else
// Null SUnit* is a noop.
EmitNoop();
- continue;
- }
-
- BB->insert(InsertPos, SU->getInstr());
- for (unsigned i = 0, e = SU->DbgInstrList.size() ; i < e ; ++i)
- BB->insert(InsertPos, SU->DbgInstrList[i]);
}
// Update the Begin iterator, as the first instruction in the block
// may have been scheduled later.
- if (!DbgValueVec.empty()) {
- for (int i = DbgValueVec.size()-1; i>=0; --i)
- if (DbgValueVec[i]!=0) {
- Begin = DbgValueVec[DbgValueVec.size()-1];
- break;
- }
- } else if (!Sequence.empty())
+ if (!Sequence.empty())
Begin = Sequence[0]->getInstr();
- DbgValueVec.clear();
+ // Reinsert any remaining debug_values.
+ for (std::vector<std::pair<MachineInstr *, MachineInstr *> >::iterator
+ DI = DbgValues.end(), DE = DbgValues.begin(); DI != DE; --DI) {
+ std::pair<MachineInstr *, MachineInstr *> P = *prior(DI);
+ MachineInstr *DbgValue = P.first;
+ MachineInstr *OrigPrivMI = P.second;
+ BB->insertAfter(OrigPrivMI, DbgValue);
+ }
+ DbgValues.clear();
+ FirstDbgValue = NULL;
return BB;
}
projects / oota-llvm.git / blobdiff