llvm::PPCHazardRecognizer970 Class Reference

PPCHazardRecognizer970 - This class defines a finite state automata that models the dispatch logic on the PowerPC 970 (aka G5) processor. More...

#include "Target/PowerPC/PPCHazardRecognizers.h"

Inheritance diagram for llvm::PPCHazardRecognizer970:

Public Member Functions
	PPCHazardRecognizer970 (const ScheduleDAG &DAG)
HazardType	getHazardType (SUnit *SU, int Stalls) override
	getHazardType - We return hazard for any non-branch instruction that would terminate the dispatch group.
void	EmitInstruction (SUnit *SU) override
	EmitInstruction - This callback is invoked when an instruction is emitted, to advance the hazard state.
void	AdvanceCycle () override
	AdvanceCycle - This callback is invoked whenever the next top-down instruction to be scheduled cannot issue in the current cycle, either because of latency or resource conflicts.
void	Reset () override
	Reset - This callback is invoked when a new block of instructions is about to be schedule.
Public Member Functions inherited from llvm::ScheduleHazardRecognizer
	ScheduleHazardRecognizer ()=default
virtual	~ScheduleHazardRecognizer ()
unsigned	getMaxLookAhead () const
bool	isEnabled () const
virtual bool	atIssueLimit () const
	atIssueLimit - Return true if no more instructions may be issued in this cycle.
virtual HazardType	getHazardType (SUnit *, int Stalls=0)
	getHazardType - Return the hazard type of emitting this node.
virtual void	Reset ()
	Reset - This callback is invoked when a new block of instructions is about to be schedule.
virtual void	EmitInstruction (SUnit *)
	EmitInstruction - This callback is invoked when an instruction is emitted, to advance the hazard state.
virtual void	EmitInstruction (MachineInstr *)
	This overload will be used when the hazard recognizer is being used by a non-scheduling pass, which does not use SUnits.
virtual unsigned	PreEmitNoops (SUnit *)
	PreEmitNoops - This callback is invoked prior to emitting an instruction.
virtual unsigned	PreEmitNoops (MachineInstr *)
	This overload will be used when the hazard recognizer is being used by a non-scheduling pass, which does not use SUnits.
virtual bool	ShouldPreferAnother (SUnit *)
	ShouldPreferAnother - This callback may be invoked if getHazardType returns NoHazard.
virtual void	AdvanceCycle ()
	AdvanceCycle - This callback is invoked whenever the next top-down instruction to be scheduled cannot issue in the current cycle, either because of latency or resource conflicts.
virtual void	RecedeCycle ()
	RecedeCycle - This callback is invoked whenever the next bottom-up instruction to be scheduled cannot issue in the current cycle, either because of latency or resource conflicts.
virtual void	EmitNoop ()
	EmitNoop - This callback is invoked when a noop was added to the instruction stream.
virtual void	EmitNoops (unsigned Quantity)
	EmitNoops - This callback is invoked when noops were added to the instruction stream.

Additional Inherited Members
Public Types inherited from llvm::ScheduleHazardRecognizer
enum	HazardType { NoHazard , Hazard , NoopHazard }
Protected Attributes inherited from llvm::ScheduleHazardRecognizer
unsigned	MaxLookAhead = 0
	MaxLookAhead - Indicate the number of cycles in the scoreboard state.

Detailed Description

PPCHazardRecognizer970 - This class defines a finite state automata that models the dispatch logic on the PowerPC 970 (aka G5) processor.

This promotes good dispatch group formation and implements noop insertion to avoid structural hazards that cause significant performance penalties (e.g. setting the CTR register then branching through it within a dispatch group), or storing then loading from the same address within a dispatch group.

Definition at line 55 of file PPCHazardRecognizers.h.

Constructor & Destructor Documentation

PPCHazardRecognizer970()

PPCHazardRecognizer970::PPCHazardRecognizer970

(

const ScheduleDAG &

DAG

)

Definition at line 262 of file PPCHazardRecognizers.cpp.

Member Function Documentation

AdvanceCycle()

void PPCHazardRecognizer970::AdvanceCycle ( )

overridevirtual

AdvanceCycle - This callback is invoked whenever the next top-down instruction to be scheduled cannot issue in the current cycle, either because of latency or resource conflicts.

This should increment the internal state of the hazard recognizer so that previously "Hazard" instructions will now not be hazards.

Reimplemented from llvm::ScheduleHazardRecognizer.

Definition at line 425 of file PPCHazardRecognizers.cpp.

References assert().

EmitInstruction()

void PPCHazardRecognizer970::EmitInstruction ( SUnit *  )

overridevirtual

EmitInstruction - This callback is invoked when an instruction is emitted, to advance the hazard state.

Reimplemented from llvm::ScheduleHazardRecognizer.

Definition at line 386 of file PPCHazardRecognizers.cpp.

References llvm::SUnit::getInstr(), llvm::MachineMemOperand::getOffset(), llvm::MachineMemOperand::getSize(), llvm::LocationSize::getValue(), llvm::MachineMemOperand::getValue(), isLoad(), isStore(), MI, llvm::PPCII::PPC970_BRU, and llvm::PPCII::PPC970_Pseudo.

getHazardType()

ScheduleHazardRecognizer::HazardType PPCHazardRecognizer970::getHazardType ( SUnit *  SU, int  Stalls  )

overridevirtual

getHazardType - We return hazard for any non-branch instruction that would terminate the dispatch group.

We turn NoopHazard for any instructions that wouldn't terminate the dispatch group that would cause a pipeline flush.

Reimplemented from llvm::ScheduleHazardRecognizer.

Definition at line 324 of file PPCHazardRecognizers.cpp.

References assert(), llvm::SUnit::getInstr(), llvm::MachineMemOperand::getOffset(), llvm::MachineMemOperand::getSize(), llvm::LocationSize::getValue(), llvm::MachineMemOperand::getValue(), llvm::LocationSize::hasValue(), llvm::ScheduleHazardRecognizer::Hazard, isLoad(), isStore(), llvm_unreachable, MI, llvm::ScheduleHazardRecognizer::NoHazard, llvm::ScheduleHazardRecognizer::NoopHazard, llvm::PPCII::PPC970_BRU, llvm::PPCII::PPC970_CRU, llvm::PPCII::PPC970_FPU, llvm::PPCII::PPC970_FXU, llvm::PPCII::PPC970_LSU, llvm::PPCII::PPC970_Pseudo, llvm::PPCII::PPC970_VALU, and llvm::PPCII::PPC970_VPERM.

Reset()

void PPCHazardRecognizer970::Reset ( )

overridevirtual

Reset - This callback is invoked when a new block of instructions is about to be schedule.

The hazard state should be set to an initialized state.

Reimplemented from llvm::ScheduleHazardRecognizer.

Definition at line 432 of file PPCHazardRecognizers.cpp.

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

• lib/Target/PowerPC/PPCHazardRecognizers.h
• lib/Target/PowerPC/PPCHazardRecognizers.cpp