v8::internal::HRedundantPhiEliminationPhase Class Reference

#include <hydrogen-redundant-phi.h>

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Public Member Functions
	HRedundantPhiEliminationPhase (HGraph *graph)
void	Run ()
void	ProcessBlock (HBasicBlock *block)
Public Member Functions inherited from v8::internal::HPhase
	HPhase (const char *name, HGraph *graph)
	~HPhase ()

Private Member Functions
void	ProcessPhis (const ZoneList< HPhi * > *phis)
	DISALLOW_COPY_AND_ASSIGN (HRedundantPhiEliminationPhase)

Additional Inherited Members
Protected Member Functions inherited from v8::internal::HPhase
HGraph *	graph () const

Detailed Description

Definition at line 16 of file hydrogen-redundant-phi.h.

Constructor & Destructor Documentation

HRedundantPhiEliminationPhase()

v8::internal::HRedundantPhiEliminationPhase::HRedundantPhiEliminationPhase ( HGraph *  graph )

inlineexplicit

Definition at line 18 of file hydrogen-redundant-phi.h.

      : HPhase("H_Redundant phi elimination", graph) { }

Member Function Documentation

DISALLOW_COPY_AND_ASSIGN()

v8::internal::HRedundantPhiEliminationPhase::DISALLOW_COPY_AND_ASSIGN ( HRedundantPhiEliminationPhase  )

private

ProcessBlock()

void v8::internal::HRedundantPhiEliminationPhase::ProcessBlock

(

HBasicBlock *

block

)

Definition at line 35 of file hydrogen-redundant-phi.cc.

                                                                   {
  ProcessPhis(block->phis());
}

References ProcessPhis().

Referenced by v8::internal::HCanonicalizePhase::Run().

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ProcessPhis()

void v8::internal::HRedundantPhiEliminationPhase::ProcessPhis ( const ZoneList< HPhi * > *  phis )

private

Definition at line 40 of file hydrogen-redundant-phi.cc.

                                                                           {
  bool updated;
  do {
    // Iterately replace all redundant phis in the given list.
    updated = false;
    for (int i = 0; i < phis->length(); i++) {
      HPhi* phi = phis->at(i);
      if (phi->CheckFlag(HValue::kIsDead)) continue;  // Already replaced.
 
      HValue* replacement = phi->GetRedundantReplacement();
      if (replacement != NULL) {
        phi->SetFlag(HValue::kIsDead);
        for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) {
          HValue* value = it.value();
          value->SetOperandAt(it.index(), replacement);
          // Iterate again if used in another non-dead phi.
          updated |= value->IsPhi() && !value->CheckFlag(HValue::kIsDead);
        }
        phi->block()->RemovePhi(phi);
      }
    }
  } while (updated);
}

References v8::internal::List< T, AllocationPolicy >::at(), v8::internal::HValue::CheckFlag(), v8::internal::HValue::IsPhi(), v8::internal::HValue::kIsDead, NULL, v8::internal::HValue::SetFlag(), and v8::internal::HValue::SetOperandAt().

Referenced by ProcessBlock(), and Run().

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Run()

void v8::internal::HRedundantPhiEliminationPhase::Run

(

)

Definition at line 10 of file hydrogen-redundant-phi.cc.

                                        {
  // Gather all phis from all blocks first.
  const ZoneList<HBasicBlock*>* blocks(graph()->blocks());
  ZoneList<HPhi*> all_phis(blocks->length(), zone());
  for (int i = 0; i < blocks->length(); ++i) {
    HBasicBlock* block = blocks->at(i);
    for (int j = 0; j < block->phis()->length(); j++) {
      all_phis.Add(block->phis()->at(j), zone());
    }
  }
 
  // Iteratively reduce all phis in the list.
  ProcessPhis(&all_phis);
 
#if DEBUG
  // Make sure that we *really* removed all redundant phis.
  for (int i = 0; i < blocks->length(); ++i) {
    for (int j = 0; j < blocks->at(i)->phis()->length(); j++) {
      DCHECK(blocks->at(i)->phis()->at(j)->GetRedundantReplacement() == NULL);
    }
  }
#endif
}

References v8::internal::List< T, AllocationPolicy >::Add(), v8::internal::List< T, AllocationPolicy >::at(), DCHECK, v8::internal::HPhase::graph(), NULL, and ProcessPhis().

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

• /mnt/V8SourceCode/src/hydrogen-redundant-phi.h
• /mnt/V8SourceCode/src/hydrogen-redundant-phi.cc