#include <MachineScheduler.h>

Inheritance diagram for llvm::GenericScheduler:

Collaboration diagram for llvm::GenericScheduler:

Public Member Functions
	GenericScheduler (const MachineSchedContext *C)
void	initPolicy (MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End, unsigned NumRegionInstrs) override
	Initialize the per-region scheduling policy.
bool	shouldTrackPressure () const override
void	initialize (ScheduleDAGMI *dag) override
	Initialize the strategy after building the DAG for a new region.
SUnit *	pickNode (bool &IsTopNode) override
	Pick the best node to balance the schedule. Implements MachineSchedStrategy.
void	schedNode (SUnit *SU, bool IsTopNode) override
void	releaseTopNode (SUnit *SU) override
void	releaseBottomNode (SUnit *SU) override
void	registerRoots () override
Protected Member Functions
void	checkAcyclicLatency ()
void	tryCandidate (SchedCandidate &Cand, SchedCandidate &TryCand, SchedBoundary &Zone, const RegPressureTracker &RPTracker, RegPressureTracker &TempTracker)
SUnit *	pickNodeBidirectional (bool &IsTopNode)
	Pick the best candidate node from either the top or bottom queue.
void	pickNodeFromQueue (SchedBoundary &Zone, const RegPressureTracker &RPTracker, SchedCandidate &Candidate)
void	reschedulePhysRegCopies (SUnit *SU, bool isTop)

Detailed Description

GenericScheduler shrinks the unscheduled zone using heuristics to balance the schedule.

Definition at line 845 of file MachineScheduler.h.

Constructor & Destructor Documentation

llvm::GenericScheduler::GenericScheduler ( const MachineSchedContext * C ) [inline]

Definition at line 854 of file MachineScheduler.h.

Member Function Documentation

void GenericScheduler::checkAcyclicLatency ( ) [protected]

Set IsAcyclicLatencyLimited if the acyclic path is longer than the cyclic critical path by more cycles than it takes to drain the instruction buffer. We estimate an upper bounds on in-flight instructions as:

CyclesPerIteration = max( CyclicPath, Loop-Resource-Height ) InFlightIterations = AcyclicPath / CyclesPerIteration InFlightResources = InFlightIterations * LoopResources

TODO: Check execution resources in addition to IssueCount.

Definition at line 2436 of file MachineScheduler.cpp.

References llvm::SchedRemainder::CriticalPath, llvm::SchedRemainder::CyclicCritPath, llvm::dbgs(), DEBUG, llvm::TargetSchedModel::getLatencyFactor(), llvm::TargetSchedModel::getMicroOpBufferSize(), llvm::TargetSchedModel::getMicroOpFactor(), llvm::SchedRemainder::IsAcyclicLatencyLimited, llvm::GenericSchedulerBase::Rem, llvm::SchedRemainder::RemIssueCount, and llvm::GenericSchedulerBase::SchedModel.

void GenericScheduler::initialize ( ScheduleDAGMI * DAG ) [override, virtual]

Initialize the strategy after building the DAG for a new region.

Implements llvm::MachineSchedStrategy.

Definition at line 2350 of file MachineScheduler.cpp.

References llvm::TargetInstrInfo::CreateTargetMIHazardRecognizer(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::TargetSchedModel::getInstrItineraries(), llvm::TargetMachine::getSubtargetImpl(), llvm::ScheduleDAGMI::hasVRegLiveness(), llvm::SchedRemainder::init(), llvm::GenericSchedulerBase::Rem, llvm::GenericSchedulerBase::SchedModel, llvm::SystemZISD::TM, and llvm::GenericSchedulerBase::TRI.

void GenericScheduler::initPolicy	(	MachineBasicBlock::iterator	Begin,
		MachineBasicBlock::iterator	End,
		unsigned	NumRegionInstrs
	)		`[override, virtual]`

Initialize the per-region scheduling policy.

Reimplemented from llvm::MachineSchedStrategy.

Definition at line 2380 of file MachineScheduler.cpp.

References llvm::GenericSchedulerBase::Context, EnableRegPressure, llvm::ForceBottomUp, llvm::ForceTopDown, llvm::RegisterClassInfo::getNumAllocatableRegs(), llvm::TargetLoweringBase::getRegClassFor(), llvm::TargetMachine::getSubtarget(), llvm::TargetMachine::getSubtargetImpl(), llvm::MachineFunction::getTarget(), llvm::TargetSubtargetInfo::getTargetLowering(), llvm::MVT::i1, llvm::MVT::i32, llvm::TargetLoweringBase::isTypeLegal(), llvm::MachineSchedContext::MF, llvm::TargetSubtargetInfo::overrideSchedPolicy(), llvm::MachineSchedContext::RegClassInfo, and llvm::SystemZISD::TM.

SUnit * GenericScheduler::pickNode ( bool & IsTopNode ) [override, virtual]

Pick the best node to balance the schedule. Implements MachineSchedStrategy.

Implements llvm::MachineSchedStrategy.

Definition at line 2771 of file MachineScheduler.cpp.

References llvm::ScheduleDAGMI::bottom(), llvm::dbgs(), DEBUG, llvm::SUnit::getInstr(), llvm::SUnit::isBottomReady(), llvm::SUnit::isScheduled, llvm::SUnit::isTopReady(), llvm::GenericSchedulerBase::NoCand, llvm::SUnit::NodeNum, llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::SchedCandidate::SU, llvm::ScheduleDAGMI::top(), and tracePick().

SUnit * GenericScheduler::pickNodeBidirectional ( bool & IsTopNode ) [protected]

Pick the best candidate node from either the top or bottom queue.

Definition at line 2712 of file MachineScheduler.cpp.

References llvm::dbgs(), DEBUG, llvm::GenericSchedulerBase::SchedCandidate::isRepeat(), llvm::GenericSchedulerBase::NoCand, llvm::GenericSchedulerBase::SchedCandidate::Policy, llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::RegCritical, llvm::GenericSchedulerBase::RegExcess, llvm::GenericSchedulerBase::setPolicy(), llvm::GenericSchedulerBase::SchedCandidate::SU, and tracePick().

void GenericScheduler::pickNodeFromQueue	(	SchedBoundary &	Zone,
		const RegPressureTracker &	RPTracker,
		SchedCandidate &	Cand
	)		`[protected]`

Pick the best candidate from the queue.

TODO: getMaxPressureDelta results can be mostly cached for each SUnit during DAG building. To adjust for the current scheduling location we need to maintain the number of vreg uses remaining to be top-scheduled.

Definition at line 2686 of file MachineScheduler.cpp.

void GenericScheduler::registerRoots ( ) [override, virtual]

Notify this strategy that all roots have been released (including those that depend on EntrySU or ExitSU).

Reimplemented from llvm::MachineSchedStrategy.

Definition at line 2464 of file MachineScheduler.cpp.

References llvm::SchedRemainder::CriticalPath, llvm::SchedRemainder::CyclicCritPath, llvm::dbgs(), DEBUG, llvm::DumpCriticalPathLength, EnableCyclicPath, llvm::errs(), llvm::ScheduleDAG::ExitSU, llvm::SUnit::getDepth(), I, and llvm::GenericSchedulerBase::Rem.

void llvm::GenericScheduler::releaseBottomNode ( SUnit * SU ) [inline, override, virtual]

When all successor dependencies have been resolved, free this node for bottom-up scheduling.

Implements llvm::MachineSchedStrategy.

Definition at line 876 of file MachineScheduler.h.

References llvm::SchedBoundary::releaseBottomNode().

void llvm::GenericScheduler::releaseTopNode ( SUnit * SU ) [inline, override, virtual]

When all predecessor dependencies have been resolved, free this node for top-down scheduling.

Implements llvm::MachineSchedStrategy.

Definition at line 872 of file MachineScheduler.h.

References llvm::SchedBoundary::releaseTopNode().

void GenericScheduler::reschedulePhysRegCopies	(	SUnit *	SU,
		bool	isTop
	)		`[protected]`

Definition at line 2817 of file MachineScheduler.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SDep::Data, llvm::dbgs(), DEBUG, llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::SUnit::getInstr(), I, llvm::MachineInstr::isCopy(), llvm::TargetRegisterInfo::isPhysicalRegister(), llvm::ScheduleDAGMI::moveInstruction(), llvm::SUnit::Preds, llvm::SmallVectorTemplateCommon< T, typename >::size(), llvm::SUnit::Succs, and llvm::GenericSchedulerBase::TRI.

void GenericScheduler::schedNode	(	SUnit *	SU,
		bool	IsTopNode
	)		`[override, virtual]`

Update the scheduler's state after scheduling a node. This is the same node that was just returned by pickNode(). However, ScheduleDAGMILive needs to update it's state based on the current cycle before MachineSchedStrategy does.

FIXME: Eventually, we may bundle physreg copies rather than rescheduling them here. See comments in biasPhysRegCopy.

Implements llvm::MachineSchedStrategy.

Definition at line 2849 of file MachineScheduler.cpp.

References llvm::SUnit::BotReadyCycle, llvm::SUnit::hasPhysRegDefs, llvm::SUnit::hasPhysRegUses, and llvm::SUnit::TopReadyCycle.

bool llvm::GenericScheduler::shouldTrackPressure ( ) const [inline, override, virtual]

Check if pressure tracking is needed before building the DAG and initializing this strategy. Called after initPolicy.

Reimplemented from llvm::MachineSchedStrategy.

Definition at line 862 of file MachineScheduler.h.

References llvm::MachineSchedPolicy::ShouldTrackPressure.

void GenericScheduler::tryCandidate	(	SchedCandidate &	Cand,
		SchedCandidate &	TryCand,
		SchedBoundary &	Zone,
		const RegPressureTracker &	RPTracker,
		RegPressureTracker &	TempTracker
	)		`[protected]`

Apply a set of heursitics to a new candidate. Heuristics are currently hierarchical. This may be more efficient than a graduated cost model because we don't need to evaluate all aspects of the model for each node in the queue. But it's really done to make the heuristics easier to debug and statistically analyze.

Parameters:

Cand	provides the policy and current best candidate.
TryCand	refers to the next SUnit candidate, otherwise uninitialized.
Zone	describes the scheduled zone that we are extending.
RPTracker	describes reg pressure within the scheduled zone.
TempTracker	is a scratch pressure tracker to reuse in queries.

Definition at line 2551 of file MachineScheduler.cpp.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation