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false::Chain Class Reference

A Chain is a sequence of instructions that are linked together by an accumulation operand. More...

Collaboration diagram for false::Chain:
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Public Member Functions

 Chain (MachineInstr *MI, unsigned Idx, Color C)
 
void add (MachineInstr *MI, unsigned Idx, Color C)
 Add a new instruction into the chain. More...
 
bool contains (MachineInstr &MI)
 Return true if MI is a member of the chain. More...
 
unsigned size () const
 Return the number of instructions in the chain. More...
 
void setKill (MachineInstr *MI, unsigned Idx, bool Immutable)
 Inform the chain that its last active register (the dest register of LastInst) is killed by MI with no intervening uses or defs. More...
 
MachineInstrgetStart () const
 Return the first instruction in the chain. More...
 
MachineInstrgetLast () const
 Return the last instruction in the chain. More...
 
MachineInstrgetKill () const
 Return the "kill" instruction (as set with setKill()) or NULL. More...
 
MachineBasicBlock::iterator end () const
 Return an instruction that can be used as an iterator for the end of the chain. More...
 
MachineBasicBlock::iterator begin () const
 
bool isKillImmutable () const
 Can the Kill instruction (assuming one exists) be modified? More...
 
Color getPreferredColor ()
 Return the preferred color of this chain. More...
 
bool rangeOverlapsWith (const Chain &Other) const
 Return true if this chain (StartInst..KillInst) overlaps with Other. More...
 
bool startsBefore (const Chain *Other) const
 Return true if this chain starts before Other. More...
 
bool requiresFixup () const
 Return true if the group will require a fixup MOV at the end. More...
 
std::string str () const
 Return a simple string representation of the chain. More...
 

Public Attributes

MachineInstrStartInst
 The important (marker) instructions. More...
 
MachineInstrLastInst
 
MachineInstrKillInst
 
unsigned StartInstIdx
 The index, from the start of the basic block, that each marker appears. More...
 
unsigned LastInstIdx
 
unsigned KillInstIdx
 
std::set< MachineInstr * > Insts
 All instructions in the chain. More...
 
bool KillIsImmutable
 True if KillInst cannot be modified. More...
 
Color LastColor
 The "color" of LastInst. More...
 

Detailed Description

A Chain is a sequence of instructions that are linked together by an accumulation operand.

For example:

fmul def d0, ? fmla def d1, ?, ?, killed d0 fmla def d2, ?, ?, killed d1

There may be other instructions interleaved in the sequence that do not belong to the chain. These other instructions must not use the "chain" register at any point.

We currently only support chains where the "chain" operand is killed at each link in the chain for simplicity. A chain has three important instructions - Start, Last and Kill.

Without a kill instruction, we must assume the outgoing value escapes beyond our model and either must not change its register or must create a fixup FMOV to keep the old register value consistent.

Definition at line 185 of file AArch64A57FPLoadBalancing.cpp.

Constructor & Destructor Documentation

◆ Chain()

false::Chain::Chain ( MachineInstr MI,
unsigned  Idx,
Color  C 
)
inline

Definition at line 203 of file AArch64A57FPLoadBalancing.cpp.

Member Function Documentation

◆ add()

void false::Chain::add ( MachineInstr MI,
unsigned  Idx,
Color  C 
)
inline

Add a new instruction into the chain.

The instruction's dest operand has the given color.

Definition at line 212 of file AArch64A57FPLoadBalancing.cpp.

References assert(), C, and MI.

◆ begin()

MachineBasicBlock::iterator false::Chain::begin ( ) const
inline

Definition at line 253 of file AArch64A57FPLoadBalancing.cpp.

Referenced by str().

◆ contains()

bool false::Chain::contains ( MachineInstr MI)
inline

Return true if MI is a member of the chain.

Definition at line 224 of file AArch64A57FPLoadBalancing.cpp.

◆ end()

MachineBasicBlock::iterator false::Chain::end ( ) const
inline

Return an instruction that can be used as an iterator for the end of the chain.

This is the maximum of KillInst (if set) and LastInst.

Definition at line 250 of file AArch64A57FPLoadBalancing.cpp.

Referenced by str().

◆ getKill()

MachineInstr* false::Chain::getKill ( ) const
inline

Return the "kill" instruction (as set with setKill()) or NULL.

Definition at line 247 of file AArch64A57FPLoadBalancing.cpp.

◆ getLast()

MachineInstr* false::Chain::getLast ( ) const
inline

Return the last instruction in the chain.

Definition at line 245 of file AArch64A57FPLoadBalancing.cpp.

◆ getPreferredColor()

Color false::Chain::getPreferredColor ( )
inline

Return the preferred color of this chain.

Definition at line 259 of file AArch64A57FPLoadBalancing.cpp.

References OverrideBalance.

◆ getStart()

MachineInstr* false::Chain::getStart ( ) const
inline

Return the first instruction in the chain.

Definition at line 243 of file AArch64A57FPLoadBalancing.cpp.

◆ isKillImmutable()

bool false::Chain::isKillImmutable ( ) const
inline

Can the Kill instruction (assuming one exists) be modified?

Definition at line 256 of file AArch64A57FPLoadBalancing.cpp.

◆ rangeOverlapsWith()

bool false::Chain::rangeOverlapsWith ( const Chain Other) const
inline

Return true if this chain (StartInst..KillInst) overlaps with Other.

Definition at line 266 of file AArch64A57FPLoadBalancing.cpp.

◆ requiresFixup()

bool false::Chain::requiresFixup ( ) const
inline

Return true if the group will require a fixup MOV at the end.

Definition at line 280 of file AArch64A57FPLoadBalancing.cpp.

Referenced by str().

◆ setKill()

void false::Chain::setKill ( MachineInstr MI,
unsigned  Idx,
bool  Immutable 
)
inline

Inform the chain that its last active register (the dest register of LastInst) is killed by MI with no intervening uses or defs.

Definition at line 233 of file AArch64A57FPLoadBalancing.cpp.

References assert(), and MI.

◆ size()

unsigned false::Chain::size ( ) const
inline

Return the number of instructions in the chain.

Definition at line 227 of file AArch64A57FPLoadBalancing.cpp.

Referenced by str().

◆ startsBefore()

bool false::Chain::startsBefore ( const Chain Other) const
inline

Return true if this chain starts before Other.

Definition at line 275 of file AArch64A57FPLoadBalancing.cpp.

References StartInstIdx.

Referenced by str().

◆ str()

std::string false::Chain::str ( ) const
inline

Member Data Documentation

◆ Insts

std::set<MachineInstr*> false::Chain::Insts

All instructions in the chain.

Definition at line 193 of file AArch64A57FPLoadBalancing.cpp.

◆ KillInst

MachineInstr * false::Chain::KillInst

Definition at line 188 of file AArch64A57FPLoadBalancing.cpp.

◆ KillInstIdx

unsigned false::Chain::KillInstIdx

Definition at line 191 of file AArch64A57FPLoadBalancing.cpp.

◆ KillIsImmutable

bool false::Chain::KillIsImmutable

True if KillInst cannot be modified.

If this is true, we cannot change LastInst's outgoing register. This will be true for tied values and regmasks.

Definition at line 197 of file AArch64A57FPLoadBalancing.cpp.

◆ LastColor

Color false::Chain::LastColor

The "color" of LastInst.

This will be the preferred chain color, as changing intermediate nodes is easy but changing the last instruction can be more tricky.

Definition at line 201 of file AArch64A57FPLoadBalancing.cpp.

◆ LastInst

MachineInstr * false::Chain::LastInst

Definition at line 188 of file AArch64A57FPLoadBalancing.cpp.

◆ LastInstIdx

unsigned false::Chain::LastInstIdx

Definition at line 191 of file AArch64A57FPLoadBalancing.cpp.

◆ StartInst

MachineInstr* false::Chain::StartInst

The important (marker) instructions.

Definition at line 188 of file AArch64A57FPLoadBalancing.cpp.

◆ StartInstIdx

unsigned false::Chain::StartInstIdx

The index, from the start of the basic block, that each marker appears.

These are stored so we can do quick interval tests.

Definition at line 191 of file AArch64A57FPLoadBalancing.cpp.

Referenced by startsBefore().


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