class MultiHazardRecognizer

Declaration

class MultiHazardRecognizer : public ScheduleHazardRecognizer { /* full declaration omitted */ };

Description

HazardRecognizer - This determines whether or not an instruction can be issued this cycle, and whether or not a noop needs to be inserted to handle the hazard.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:25

Inherits from: ScheduleHazardRecognizer

Member Variables

private SmallVector< std::unique_ptr<ScheduleHazardRecognizer>, 4> Recognizers

Inherited from ScheduleHazardRecognizer:

protected MaxLookAhead = 0

Method Overview

• public void AddHazardRecognizer(std::unique_ptr<ScheduleHazardRecognizer> &&)
• public void AdvanceCycle()
• public void EmitInstruction(llvm::SUnit *)
• public void EmitInstruction(llvm::MachineInstr *)
• public void EmitNoop()
• public MultiHazardRecognizer()
• public unsigned int PreEmitNoops(llvm::SUnit *)
• public unsigned int PreEmitNoops(llvm::MachineInstr *)
• public void RecedeCycle()
• public void Reset()
• public bool ShouldPreferAnother(llvm::SUnit *)
• public bool atIssueLimit() const
• public llvm::ScheduleHazardRecognizer::HazardType getHazardType(llvm::SUnit *, int Stalls = 0)

Inherited from ScheduleHazardRecognizer:

• public AdvanceCycle
• public EmitInstruction
• public EmitInstruction
• public EmitNoop
• public EmitNoops
• public PreEmitNoops
• public PreEmitNoops
• public RecedeCycle
• public Reset
• public ShouldPreferAnother
• public atIssueLimit
• public getHazardType
• public getMaxLookAhead
• public isEnabled

Methods

¶void AddHazardRecognizer(
    std::unique_ptr<ScheduleHazardRecognizer>&&)

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:30

Parameters

std::unique_ptr<ScheduleHazardRecognizer>&&

¶void AdvanceCycle()

Description

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.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:40

¶void EmitInstruction(llvm::SUnit*)

Description

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

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:35

Parameters

llvm::SUnit*

¶void EmitInstruction(llvm::MachineInstr*)

Description

This overload will be used when the hazard recognizer is being used by a non-scheduling pass, which does not use SUnits.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:36

Parameters

llvm::MachineInstr*

¶void EmitNoop()

Description

EmitNoop - This callback is invoked when a noop was added to the instruction stream.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:42

¶MultiHazardRecognizer()

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:29

¶unsigned int PreEmitNoops(llvm::SUnit*)

Description

PreEmitNoops - This callback is invoked prior to emitting an instruction. It should return the number of noops to emit prior to the provided instruction. Note: This is only used during PostRA scheduling. EmitNoop is not called for these noops.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:37

Parameters

llvm::SUnit*

¶unsigned int PreEmitNoops(llvm::MachineInstr*)

Description

This overload will be used when the hazard recognizer is being used by a non-scheduling pass, which does not use SUnits.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:38

Parameters

llvm::MachineInstr*

¶void RecedeCycle()

Description

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.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:41

¶void Reset()

Description

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.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:34

¶bool ShouldPreferAnother(llvm::SUnit*)

Description

ShouldPreferAnother - This callback may be invoked if getHazardType returns NoHazard. If, even though there is no hazard, it would be better to schedule another available instruction, this callback should return true.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:39

Parameters

llvm::SUnit*

¶bool atIssueLimit() const

Description

atIssueLimit - Return true if no more instructions may be issued in this cycle. FIXME: remove this once MachineScheduler is the only client.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:32

¶llvm::ScheduleHazardRecognizer::HazardType
getHazardType(llvm::SUnit*, int Stalls = 0)

Description

getHazardType - Return the hazard type of emitting this node. There are three possible results. Either: * NoHazard: it is legal to issue this instruction on this cycle. * Hazard: issuing this instruction would stall the machine. If some other instruction is available, issue it first. * NoopHazard: issuing this instruction would break the program. If some other instruction can be issued, do so, otherwise issue a noop.

Declared at: llvm/include/llvm/CodeGen/MultiHazardRecognizer.h:33

Parameters

llvm::SUnit*

int Stalls = 0