Move Hydrogen and Lithium to src/crankshaft/

src/lithium-allocator.cc

Index: src/lithium-allocator.cc
diff --git a/src/lithium-allocator.cc b/src/lithium-allocator.cc
deleted file mode 100644
index 7e34daab411dba2f93ff19e838c511fca1b83236..0000000000000000000000000000000000000000
--- a/src/lithium-allocator.cc
+++ /dev/null
@@ -1,2194 +0,0 @@
-// Copyright 2012 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "src/lithium-allocator.h"
-
-#include "src/hydrogen.h"
-#include "src/lithium-inl.h"
-#include "src/lithium-allocator-inl.h"
-#include "src/register-configuration.h"
-#include "src/string-stream.h"
-
-namespace v8 {
-namespace internal {
-
-static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) {
-  return a.Value() < b.Value() ? a : b;
-}
-
-
-static inline LifetimePosition Max(LifetimePosition a, LifetimePosition b) {
-  return a.Value() > b.Value() ? a : b;
-}
-
-
-UsePosition::UsePosition(LifetimePosition pos,
-                         LOperand* operand,
-                         LOperand* hint)
-    : operand_(operand),
-      hint_(hint),
-      pos_(pos),
-      next_(NULL),
-      requires_reg_(false),
-      register_beneficial_(true) {
-  if (operand_ != NULL && operand_->IsUnallocated()) {
-    LUnallocated* unalloc = LUnallocated::cast(operand_);
-    requires_reg_ = unalloc->HasRegisterPolicy() ||
-        unalloc->HasDoubleRegisterPolicy();
-    register_beneficial_ = !unalloc->HasAnyPolicy();
-  }
-  DCHECK(pos_.IsValid());
-}
-
-
-bool UsePosition::HasHint() const {
-  return hint_ != NULL && !hint_->IsUnallocated();
-}
-
-
-bool UsePosition::RequiresRegister() const {
-  return requires_reg_;
-}
-
-
-bool UsePosition::RegisterIsBeneficial() const {
-  return register_beneficial_;
-}
-
-
-void UseInterval::SplitAt(LifetimePosition pos, Zone* zone) {
-  DCHECK(Contains(pos) && pos.Value() != start().Value());
-  UseInterval* after = new(zone) UseInterval(pos, end_);
-  after->next_ = next_;
-  next_ = after;
-  end_ = pos;
-}
-
-
-#ifdef DEBUG
-
-
-void LiveRange::Verify() const {
-  UsePosition* cur = first_pos_;
-  while (cur != NULL) {
-    DCHECK(Start().Value() <= cur->pos().Value() &&
-           cur->pos().Value() <= End().Value());
-    cur = cur->next();
-  }
-}
-
-
-bool LiveRange::HasOverlap(UseInterval* target) const {
-  UseInterval* current_interval = first_interval_;
-  while (current_interval != NULL) {
-    // Intervals overlap if the start of one is contained in the other.
-    if (current_interval->Contains(target->start()) ||
-        target->Contains(current_interval->start())) {
-      return true;
-    }
-    current_interval = current_interval->next();
-  }
-  return false;
-}
-
-
-#endif
-
-
-LiveRange::LiveRange(int id, Zone* zone)
-    : id_(id),
-      spilled_(false),
-      kind_(UNALLOCATED_REGISTERS),
-      assigned_register_(kInvalidAssignment),
-      last_interval_(NULL),
-      first_interval_(NULL),
-      first_pos_(NULL),
-      parent_(NULL),
-      next_(NULL),
-      current_interval_(NULL),
-      last_processed_use_(NULL),
-      current_hint_operand_(NULL),
-      spill_operand_(new (zone) LOperand()),
-      spill_start_index_(kMaxInt) {}
-
-
-void LiveRange::set_assigned_register(int reg, Zone* zone) {
-  DCHECK(!HasRegisterAssigned() && !IsSpilled());
-  assigned_register_ = reg;
-  ConvertOperands(zone);
-}
-
-
-void LiveRange::MakeSpilled(Zone* zone) {
-  DCHECK(!IsSpilled());
-  DCHECK(TopLevel()->HasAllocatedSpillOperand());
-  spilled_ = true;
-  assigned_register_ = kInvalidAssignment;
-  ConvertOperands(zone);
-}
-
-
-bool LiveRange::HasAllocatedSpillOperand() const {
-  DCHECK(spill_operand_ != NULL);
-  return !spill_operand_->IsIgnored();
-}
-
-
-void LiveRange::SetSpillOperand(LOperand* operand) {
-  DCHECK(!operand->IsUnallocated());
-  DCHECK(spill_operand_ != NULL);
-  DCHECK(spill_operand_->IsIgnored());
-  spill_operand_->ConvertTo(operand->kind(), operand->index());
-}
-
-
-UsePosition* LiveRange::NextUsePosition(LifetimePosition start) {
-  UsePosition* use_pos = last_processed_use_;
-  if (use_pos == NULL) use_pos = first_pos();
-  while (use_pos != NULL && use_pos->pos().Value() < start.Value()) {
-    use_pos = use_pos->next();
-  }
-  last_processed_use_ = use_pos;
-  return use_pos;
-}
-
-
-UsePosition* LiveRange::NextUsePositionRegisterIsBeneficial(
-    LifetimePosition start) {
-  UsePosition* pos = NextUsePosition(start);
-  while (pos != NULL && !pos->RegisterIsBeneficial()) {
-    pos = pos->next();
-  }
-  return pos;
-}
-
-
-UsePosition* LiveRange::PreviousUsePositionRegisterIsBeneficial(
-    LifetimePosition start) {
-  UsePosition* pos = first_pos();
-  UsePosition* prev = NULL;
-  while (pos != NULL && pos->pos().Value() < start.Value()) {
-    if (pos->RegisterIsBeneficial()) prev = pos;
-    pos = pos->next();
-  }
-  return prev;
-}
-
-
-UsePosition* LiveRange::NextRegisterPosition(LifetimePosition start) {
-  UsePosition* pos = NextUsePosition(start);
-  while (pos != NULL && !pos->RequiresRegister()) {
-    pos = pos->next();
-  }
-  return pos;
-}
-
-
-bool LiveRange::CanBeSpilled(LifetimePosition pos) {
-  // We cannot spill a live range that has a use requiring a register
-  // at the current or the immediate next position.
-  UsePosition* use_pos = NextRegisterPosition(pos);
-  if (use_pos == NULL) return true;
-  return
-      use_pos->pos().Value() > pos.NextInstruction().InstructionEnd().Value();
-}
-
-
-LOperand* LiveRange::CreateAssignedOperand(Zone* zone) {
-  LOperand* op = NULL;
-  if (HasRegisterAssigned()) {
-    DCHECK(!IsSpilled());
-    switch (Kind()) {
-      case GENERAL_REGISTERS:
-        op = LRegister::Create(assigned_register(), zone);
-        break;
-      case DOUBLE_REGISTERS:
-        op = LDoubleRegister::Create(assigned_register(), zone);
-        break;
-      default:
-        UNREACHABLE();
-    }
-  } else if (IsSpilled()) {
-    DCHECK(!HasRegisterAssigned());
-    op = TopLevel()->GetSpillOperand();
-    DCHECK(!op->IsUnallocated());
-  } else {
-    LUnallocated* unalloc = new(zone) LUnallocated(LUnallocated::NONE);
-    unalloc->set_virtual_register(id_);
-    op = unalloc;
-  }
-  return op;
-}
-
-
-UseInterval* LiveRange::FirstSearchIntervalForPosition(
-    LifetimePosition position) const {
-  if (current_interval_ == NULL) return first_interval_;
-  if (current_interval_->start().Value() > position.Value()) {
-    current_interval_ = NULL;
-    return first_interval_;
-  }
-  return current_interval_;
-}
-
-
-void LiveRange::AdvanceLastProcessedMarker(
-    UseInterval* to_start_of, LifetimePosition but_not_past) const {
-  if (to_start_of == NULL) return;
-  if (to_start_of->start().Value() > but_not_past.Value()) return;
-  LifetimePosition start =
-      current_interval_ == NULL ? LifetimePosition::Invalid()
-                                : current_interval_->start();
-  if (to_start_of->start().Value() > start.Value()) {
-    current_interval_ = to_start_of;
-  }
-}
-
-
-void LiveRange::SplitAt(LifetimePosition position,
-                        LiveRange* result,
-                        Zone* zone) {
-  DCHECK(Start().Value() < position.Value());
-  DCHECK(result->IsEmpty());
-  // Find the last interval that ends before the position. If the
-  // position is contained in one of the intervals in the chain, we
-  // split that interval and use the first part.
-  UseInterval* current = FirstSearchIntervalForPosition(position);
-
-  // If the split position coincides with the beginning of a use interval
-  // we need to split use positons in a special way.
-  bool split_at_start = false;
-
-  if (current->start().Value() == position.Value()) {
-    // When splitting at start we need to locate the previous use interval.
-    current = first_interval_;
-  }
-
-  while (current != NULL) {
-    if (current->Contains(position)) {
-      current->SplitAt(position, zone);
-      break;
-    }
-    UseInterval* next = current->next();
-    if (next->start().Value() >= position.Value()) {
-      split_at_start = (next->start().Value() == position.Value());
-      break;
-    }
-    current = next;
-  }
-
-  // Partition original use intervals to the two live ranges.
-  UseInterval* before = current;
-  UseInterval* after = before->next();
-  result->last_interval_ = (last_interval_ == before)
-      ? after            // Only interval in the range after split.
-      : last_interval_;  // Last interval of the original range.
-  result->first_interval_ = after;
-  last_interval_ = before;
-
-  // Find the last use position before the split and the first use
-  // position after it.
-  UsePosition* use_after = first_pos_;
-  UsePosition* use_before = NULL;
-  if (split_at_start) {
-    // The split position coincides with the beginning of a use interval (the
-    // end of a lifetime hole). Use at this position should be attributed to
-    // the split child because split child owns use interval covering it.
-    while (use_after != NULL && use_after->pos().Value() < position.Value()) {
-      use_before = use_after;
-      use_after = use_after->next();
-    }
-  } else {
-    while (use_after != NULL && use_after->pos().Value() <= position.Value()) {
-      use_before = use_after;
-      use_after = use_after->next();
-    }
-  }
-
-  // Partition original use positions to the two live ranges.
-  if (use_before != NULL) {
-    use_before->next_ = NULL;
-  } else {
-    first_pos_ = NULL;
-  }
-  result->first_pos_ = use_after;
-
-  // Discard cached iteration state. It might be pointing
-  // to the use that no longer belongs to this live range.
-  last_processed_use_ = NULL;
-  current_interval_ = NULL;
-
-  // Link the new live range in the chain before any of the other
-  // ranges linked from the range before the split.
-  result->parent_ = (parent_ == NULL) ? this : parent_;
-  result->kind_ = result->parent_->kind_;
-  result->next_ = next_;
-  next_ = result;
-
-#ifdef DEBUG
-  Verify();
-  result->Verify();
-#endif
-}
-
-
-// This implements an ordering on live ranges so that they are ordered by their
-// start positions.  This is needed for the correctness of the register
-// allocation algorithm.  If two live ranges start at the same offset then there
-// is a tie breaker based on where the value is first used.  This part of the
-// ordering is merely a heuristic.
-bool LiveRange::ShouldBeAllocatedBefore(const LiveRange* other) const {
-  LifetimePosition start = Start();
-  LifetimePosition other_start = other->Start();
-  if (start.Value() == other_start.Value()) {
-    UsePosition* pos = first_pos();
-    if (pos == NULL) return false;
-    UsePosition* other_pos = other->first_pos();
-    if (other_pos == NULL) return true;
-    return pos->pos().Value() < other_pos->pos().Value();
-  }
-  return start.Value() < other_start.Value();
-}
-
-
-void LiveRange::ShortenTo(LifetimePosition start) {
-  LAllocator::TraceAlloc("Shorten live range %d to [%d\n", id_, start.Value());
-  DCHECK(first_interval_ != NULL);
-  DCHECK(first_interval_->start().Value() <= start.Value());
-  DCHECK(start.Value() < first_interval_->end().Value());
-  first_interval_->set_start(start);
-}
-
-
-void LiveRange::EnsureInterval(LifetimePosition start,
-                               LifetimePosition end,
-                               Zone* zone) {
-  LAllocator::TraceAlloc("Ensure live range %d in interval [%d %d[\n",
-                         id_,
-                         start.Value(),
-                         end.Value());
-  LifetimePosition new_end = end;
-  while (first_interval_ != NULL &&
-         first_interval_->start().Value() <= end.Value()) {
-    if (first_interval_->end().Value() > end.Value()) {
-      new_end = first_interval_->end();
-    }
-    first_interval_ = first_interval_->next();
-  }
-
-  UseInterval* new_interval = new(zone) UseInterval(start, new_end);
-  new_interval->next_ = first_interval_;
-  first_interval_ = new_interval;
-  if (new_interval->next() == NULL) {
-    last_interval_ = new_interval;
-  }
-}
-
-
-void LiveRange::AddUseInterval(LifetimePosition start,
-                               LifetimePosition end,
-                               Zone* zone) {
-  LAllocator::TraceAlloc("Add to live range %d interval [%d %d[\n",
-                         id_,
-                         start.Value(),
-                         end.Value());
-  if (first_interval_ == NULL) {
-    UseInterval* interval = new(zone) UseInterval(start, end);
-    first_interval_ = interval;
-    last_interval_ = interval;
-  } else {
-    if (end.Value() == first_interval_->start().Value()) {
-      first_interval_->set_start(start);
-    } else if (end.Value() < first_interval_->start().Value()) {
-      UseInterval* interval = new(zone) UseInterval(start, end);
-      interval->set_next(first_interval_);
-      first_interval_ = interval;
-    } else {
-      // Order of instruction's processing (see ProcessInstructions) guarantees
-      // that each new use interval either precedes or intersects with
-      // last added interval.
-      DCHECK(start.Value() < first_interval_->end().Value());
-      first_interval_->start_ = Min(start, first_interval_->start_);
-      first_interval_->end_ = Max(end, first_interval_->end_);
-    }
-  }
-}
-
-
-void LiveRange::AddUsePosition(LifetimePosition pos,
-                               LOperand* operand,
-                               LOperand* hint,
-                               Zone* zone) {
-  LAllocator::TraceAlloc("Add to live range %d use position %d\n",
-                         id_,
-                         pos.Value());
-  UsePosition* use_pos = new(zone) UsePosition(pos, operand, hint);
-  UsePosition* prev_hint = NULL;
-  UsePosition* prev = NULL;
-  UsePosition* current = first_pos_;
-  while (current != NULL && current->pos().Value() < pos.Value()) {
-    prev_hint = current->HasHint() ? current : prev_hint;
-    prev = current;
-    current = current->next();
-  }
-
-  if (prev == NULL) {
-    use_pos->set_next(first_pos_);
-    first_pos_ = use_pos;
-  } else {
-    use_pos->next_ = prev->next_;
-    prev->next_ = use_pos;
-  }
-
-  if (prev_hint == NULL && use_pos->HasHint()) {
-    current_hint_operand_ = hint;
-  }
-}
-
-
-void LiveRange::ConvertOperands(Zone* zone) {
-  LOperand* op = CreateAssignedOperand(zone);
-  UsePosition* use_pos = first_pos();
-  while (use_pos != NULL) {
-    DCHECK(Start().Value() <= use_pos->pos().Value() &&
-           use_pos->pos().Value() <= End().Value());
-
-    if (use_pos->HasOperand()) {
-      DCHECK(op->IsRegister() || op->IsDoubleRegister() ||
-             !use_pos->RequiresRegister());
-      use_pos->operand()->ConvertTo(op->kind(), op->index());
-    }
-    use_pos = use_pos->next();
-  }
-}
-
-
-bool LiveRange::CanCover(LifetimePosition position) const {
-  if (IsEmpty()) return false;
-  return Start().Value() <= position.Value() &&
-         position.Value() < End().Value();
-}
-
-
-bool LiveRange::Covers(LifetimePosition position) {
-  if (!CanCover(position)) return false;
-  UseInterval* start_search = FirstSearchIntervalForPosition(position);
-  for (UseInterval* interval = start_search;
-       interval != NULL;
-       interval = interval->next()) {
-    DCHECK(interval->next() == NULL ||
-           interval->next()->start().Value() >= interval->start().Value());
-    AdvanceLastProcessedMarker(interval, position);
-    if (interval->Contains(position)) return true;
-    if (interval->start().Value() > position.Value()) return false;
-  }
-  return false;
-}
-
-
-LifetimePosition LiveRange::FirstIntersection(LiveRange* other) {
-  UseInterval* b = other->first_interval();
-  if (b == NULL) return LifetimePosition::Invalid();
-  LifetimePosition advance_last_processed_up_to = b->start();
-  UseInterval* a = FirstSearchIntervalForPosition(b->start());
-  while (a != NULL && b != NULL) {
-    if (a->start().Value() > other->End().Value()) break;
-    if (b->start().Value() > End().Value()) break;
-    LifetimePosition cur_intersection = a->Intersect(b);
-    if (cur_intersection.IsValid()) {
-      return cur_intersection;
-    }
-    if (a->start().Value() < b->start().Value()) {
-      a = a->next();
-      if (a == NULL || a->start().Value() > other->End().Value()) break;
-      AdvanceLastProcessedMarker(a, advance_last_processed_up_to);
-    } else {
-      b = b->next();
-    }
-  }
-  return LifetimePosition::Invalid();
-}
-
-
-LAllocator::LAllocator(int num_values, HGraph* graph)
-    : chunk_(NULL),
-      live_in_sets_(graph->blocks()->length(), zone()),
-      live_ranges_(num_values * 2, zone()),
-      fixed_live_ranges_(NULL),
-      fixed_double_live_ranges_(NULL),
-      unhandled_live_ranges_(num_values * 2, zone()),
-      active_live_ranges_(8, zone()),
-      inactive_live_ranges_(8, zone()),
-      reusable_slots_(8, zone()),
-      next_virtual_register_(num_values),
-      first_artificial_register_(num_values),
-      mode_(UNALLOCATED_REGISTERS),
-      num_registers_(-1),
-      graph_(graph),
-      has_osr_entry_(false),
-      allocation_ok_(true) {}
-
-
-void LAllocator::InitializeLivenessAnalysis() {
-  // Initialize the live_in sets for each block to NULL.
-  int block_count = graph_->blocks()->length();
-  live_in_sets_.Initialize(block_count, zone());
-  live_in_sets_.AddBlock(NULL, block_count, zone());
-}
-
-
-BitVector* LAllocator::ComputeLiveOut(HBasicBlock* block) {
-  // Compute live out for the given block, except not including backward
-  // successor edges.
-  BitVector* live_out = new(zone()) BitVector(next_virtual_register_, zone());
-
-  // Process all successor blocks.
-  for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) {
-    // Add values live on entry to the successor. Note the successor's
-    // live_in will not be computed yet for backwards edges.
-    HBasicBlock* successor = it.Current();
-    BitVector* live_in = live_in_sets_[successor->block_id()];
-    if (live_in != NULL) live_out->Union(*live_in);
-
-    // All phi input operands corresponding to this successor edge are live
-    // out from this block.
-    int index = successor->PredecessorIndexOf(block);
-    const ZoneList<HPhi*>* phis = successor->phis();
-    for (int i = 0; i < phis->length(); ++i) {
-      HPhi* phi = phis->at(i);
-      if (!phi->OperandAt(index)->IsConstant()) {
-        live_out->Add(phi->OperandAt(index)->id());
-      }
-    }
-  }
-
-  return live_out;
-}
-
-
-void LAllocator::AddInitialIntervals(HBasicBlock* block,
-                                     BitVector* live_out) {
-  // Add an interval that includes the entire block to the live range for
-  // each live_out value.
-  LifetimePosition start = LifetimePosition::FromInstructionIndex(
-      block->first_instruction_index());
-  LifetimePosition end = LifetimePosition::FromInstructionIndex(
-      block->last_instruction_index()).NextInstruction();
-  BitVector::Iterator iterator(live_out);
-  while (!iterator.Done()) {
-    int operand_index = iterator.Current();
-    LiveRange* range = LiveRangeFor(operand_index);
-    range->AddUseInterval(start, end, zone());
-    iterator.Advance();
-  }
-}
-
-
-int LAllocator::FixedDoubleLiveRangeID(int index) {
-  return -index - 1 - Register::kNumRegisters;
-}
-
-
-LOperand* LAllocator::AllocateFixed(LUnallocated* operand,
-                                    int pos,
-                                    bool is_tagged) {
-  TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register());
-  DCHECK(operand->HasFixedPolicy());
-  if (operand->HasFixedSlotPolicy()) {
-    operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_slot_index());
-  } else if (operand->HasFixedRegisterPolicy()) {
-    int reg_index = operand->fixed_register_index();
-    operand->ConvertTo(LOperand::REGISTER, reg_index);
-  } else if (operand->HasFixedDoubleRegisterPolicy()) {
-    int reg_index = operand->fixed_register_index();
-    operand->ConvertTo(LOperand::DOUBLE_REGISTER, reg_index);
-  } else {
-    UNREACHABLE();
-  }
-  if (is_tagged) {
-    TraceAlloc("Fixed reg is tagged at %d\n", pos);
-    LInstruction* instr = InstructionAt(pos);
-    if (instr->HasPointerMap()) {
-      instr->pointer_map()->RecordPointer(operand, chunk()->zone());
-    }
-  }
-  return operand;
-}
-
-
-LiveRange* LAllocator::FixedLiveRangeFor(int index) {
-  DCHECK(index < Register::kNumRegisters);
-  LiveRange* result = fixed_live_ranges_[index];
-  if (result == NULL) {
-    result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone());
-    DCHECK(result->IsFixed());
-    result->kind_ = GENERAL_REGISTERS;
-    SetLiveRangeAssignedRegister(result, index);
-    fixed_live_ranges_[index] = result;
-  }
-  return result;
-}
-
-
-LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) {
-  DCHECK(index < DoubleRegister::kMaxNumRegisters);
-  LiveRange* result = fixed_double_live_ranges_[index];
-  if (result == NULL) {
-    result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index),
-                                   chunk()->zone());
-    DCHECK(result->IsFixed());
-    result->kind_ = DOUBLE_REGISTERS;
-    SetLiveRangeAssignedRegister(result, index);
-    fixed_double_live_ranges_[index] = result;
-  }
-  return result;
-}
-
-
-LiveRange* LAllocator::LiveRangeFor(int index) {
-  if (index >= live_ranges_.length()) {
-    live_ranges_.AddBlock(NULL, index - live_ranges_.length() + 1, zone());
-  }
-  LiveRange* result = live_ranges_[index];
-  if (result == NULL) {
-    result = new(zone()) LiveRange(index, chunk()->zone());
-    live_ranges_[index] = result;
-  }
-  return result;
-}
-
-
-LGap* LAllocator::GetLastGap(HBasicBlock* block) {
-  int last_instruction = block->last_instruction_index();
-  int index = chunk_->NearestGapPos(last_instruction);
-  return GapAt(index);
-}
-
-
-HPhi* LAllocator::LookupPhi(LOperand* operand) const {
-  if (!operand->IsUnallocated()) return NULL;
-  int index = LUnallocated::cast(operand)->virtual_register();
-  HValue* instr = graph_->LookupValue(index);
-  if (instr != NULL && instr->IsPhi()) {
-    return HPhi::cast(instr);
-  }
-  return NULL;
-}
-
-
-LiveRange* LAllocator::LiveRangeFor(LOperand* operand) {
-  if (operand->IsUnallocated()) {
-    return LiveRangeFor(LUnallocated::cast(operand)->virtual_register());
-  } else if (operand->IsRegister()) {
-    return FixedLiveRangeFor(operand->index());
-  } else if (operand->IsDoubleRegister()) {
-    return FixedDoubleLiveRangeFor(operand->index());
-  } else {
-    return NULL;
-  }
-}
-
-
-void LAllocator::Define(LifetimePosition position,
-                        LOperand* operand,
-                        LOperand* hint) {
-  LiveRange* range = LiveRangeFor(operand);
-  if (range == NULL) return;
-
-  if (range->IsEmpty() || range->Start().Value() > position.Value()) {
-    // Can happen if there is a definition without use.
-    range->AddUseInterval(position, position.NextInstruction(), zone());
-    range->AddUsePosition(position.NextInstruction(), NULL, NULL, zone());
-  } else {
-    range->ShortenTo(position);
-  }
-
-  if (operand->IsUnallocated()) {
-    LUnallocated* unalloc_operand = LUnallocated::cast(operand);
-    range->AddUsePosition(position, unalloc_operand, hint, zone());
-  }
-}
-
-
-void LAllocator::Use(LifetimePosition block_start,
-                     LifetimePosition position,
-                     LOperand* operand,
-                     LOperand* hint) {
-  LiveRange* range = LiveRangeFor(operand);
-  if (range == NULL) return;
-  if (operand->IsUnallocated()) {
-    LUnallocated* unalloc_operand = LUnallocated::cast(operand);
-    range->AddUsePosition(position, unalloc_operand, hint, zone());
-  }
-  range->AddUseInterval(block_start, position, zone());
-}
-
-
-void LAllocator::AddConstraintsGapMove(int index,
-                                       LOperand* from,
-                                       LOperand* to) {
-  LGap* gap = GapAt(index);
-  LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
-                                                     chunk()->zone());
-  if (from->IsUnallocated()) {
-    const ZoneList<LMoveOperands>* move_operands = move->move_operands();
-    for (int i = 0; i < move_operands->length(); ++i) {
-      LMoveOperands cur = move_operands->at(i);
-      LOperand* cur_to = cur.destination();
-      if (cur_to->IsUnallocated()) {
-        if (LUnallocated::cast(cur_to)->virtual_register() ==
-            LUnallocated::cast(from)->virtual_register()) {
-          move->AddMove(cur.source(), to, chunk()->zone());
-          return;
-        }
-      }
-    }
-  }
-  move->AddMove(from, to, chunk()->zone());
-}
-
-
-void LAllocator::MeetRegisterConstraints(HBasicBlock* block) {
-  int start = block->first_instruction_index();
-  int end = block->last_instruction_index();
-  if (start == -1) return;
-  for (int i = start; i <= end; ++i) {
-    if (IsGapAt(i)) {
-      LInstruction* instr = NULL;
-      LInstruction* prev_instr = NULL;
-      if (i < end) instr = InstructionAt(i + 1);
-      if (i > start) prev_instr = InstructionAt(i - 1);
-      MeetConstraintsBetween(prev_instr, instr, i);
-      if (!AllocationOk()) return;
-    }
-  }
-}
-
-
-void LAllocator::MeetConstraintsBetween(LInstruction* first,
-                                        LInstruction* second,
-                                        int gap_index) {
-  // Handle fixed temporaries.
-  if (first != NULL) {
-    for (TempIterator it(first); !it.Done(); it.Advance()) {
-      LUnallocated* temp = LUnallocated::cast(it.Current());
-      if (temp->HasFixedPolicy()) {
-        AllocateFixed(temp, gap_index - 1, false);
-      }
-    }
-  }
-
-  // Handle fixed output operand.
-  if (first != NULL && first->Output() != NULL) {
-    LUnallocated* first_output = LUnallocated::cast(first->Output());
-    LiveRange* range = LiveRangeFor(first_output->virtual_register());
-    bool assigned = false;
-    if (first_output->HasFixedPolicy()) {
-      LUnallocated* output_copy = first_output->CopyUnconstrained(
-          chunk()->zone());
-      bool is_tagged = HasTaggedValue(first_output->virtual_register());
-      AllocateFixed(first_output, gap_index, is_tagged);
-
-      // This value is produced on the stack, we never need to spill it.
-      if (first_output->IsStackSlot()) {
-        range->SetSpillOperand(first_output);
-        range->SetSpillStartIndex(gap_index - 1);
-        assigned = true;
-      }
-      chunk_->AddGapMove(gap_index, first_output, output_copy);
-    }
-
-    if (!assigned) {
-      range->SetSpillStartIndex(gap_index);
-
-      // This move to spill operand is not a real use. Liveness analysis
-      // and splitting of live ranges do not account for it.
-      // Thus it should be inserted to a lifetime position corresponding to
-      // the instruction end.
-      LGap* gap = GapAt(gap_index);
-      LParallelMove* move = gap->GetOrCreateParallelMove(LGap::BEFORE,
-                                                         chunk()->zone());
-      move->AddMove(first_output, range->GetSpillOperand(),
-                    chunk()->zone());
-    }
-  }
-
-  // Handle fixed input operands of second instruction.
-  if (second != NULL) {
-    for (UseIterator it(second); !it.Done(); it.Advance()) {
-      LUnallocated* cur_input = LUnallocated::cast(it.Current());
-      if (cur_input->HasFixedPolicy()) {
-        LUnallocated* input_copy = cur_input->CopyUnconstrained(
-            chunk()->zone());
-        bool is_tagged = HasTaggedValue(cur_input->virtual_register());
-        AllocateFixed(cur_input, gap_index + 1, is_tagged);
-        AddConstraintsGapMove(gap_index, input_copy, cur_input);
-      } else if (cur_input->HasWritableRegisterPolicy()) {
-        // The live range of writable input registers always goes until the end
-        // of the instruction.
-        DCHECK(!cur_input->IsUsedAtStart());
-
-        LUnallocated* input_copy = cur_input->CopyUnconstrained(
-            chunk()->zone());
-        int vreg = GetVirtualRegister();
-        if (!AllocationOk()) return;
-        cur_input->set_virtual_register(vreg);
-
-        if (RequiredRegisterKind(input_copy->virtual_register()) ==
-            DOUBLE_REGISTERS) {
-          double_artificial_registers_.Add(
-              cur_input->virtual_register() - first_artificial_register_,
-              zone());
-        }
-
-        AddConstraintsGapMove(gap_index, input_copy, cur_input);
-      }
-    }
-  }
-
-  // Handle "output same as input" for second instruction.
-  if (second != NULL && second->Output() != NULL) {
-    LUnallocated* second_output = LUnallocated::cast(second->Output());
-    if (second_output->HasSameAsInputPolicy()) {
-      LUnallocated* cur_input = LUnallocated::cast(second->FirstInput());
-      int output_vreg = second_output->virtual_register();
-      int input_vreg = cur_input->virtual_register();
-
-      LUnallocated* input_copy = cur_input->CopyUnconstrained(
-          chunk()->zone());
-      cur_input->set_virtual_register(second_output->virtual_register());
-      AddConstraintsGapMove(gap_index, input_copy, cur_input);
-
-      if (HasTaggedValue(input_vreg) && !HasTaggedValue(output_vreg)) {
-        int index = gap_index + 1;
-        LInstruction* instr = InstructionAt(index);
-        if (instr->HasPointerMap()) {
-          instr->pointer_map()->RecordPointer(input_copy, chunk()->zone());
-        }
-      } else if (!HasTaggedValue(input_vreg) && HasTaggedValue(output_vreg)) {
-        // The input is assumed to immediately have a tagged representation,
-        // before the pointer map can be used. I.e. the pointer map at the
-        // instruction will include the output operand (whose value at the
-        // beginning of the instruction is equal to the input operand). If
-        // this is not desired, then the pointer map at this instruction needs
-        // to be adjusted manually.
-      }
-    }
-  }
-}
-
-
-void LAllocator::ProcessInstructions(HBasicBlock* block, BitVector* live) {
-  int block_start = block->first_instruction_index();
-  int index = block->last_instruction_index();
-
-  LifetimePosition block_start_position =
-      LifetimePosition::FromInstructionIndex(block_start);
-
-  while (index >= block_start) {
-    LifetimePosition curr_position =
-        LifetimePosition::FromInstructionIndex(index);
-
-    if (IsGapAt(index)) {
-      // We have a gap at this position.
-      LGap* gap = GapAt(index);
-      LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
-                                                         chunk()->zone());
-      const ZoneList<LMoveOperands>* move_operands = move->move_operands();
-      for (int i = 0; i < move_operands->length(); ++i) {
-        LMoveOperands* cur = &move_operands->at(i);
-        if (cur->IsIgnored()) continue;
-        LOperand* from = cur->source();
-        LOperand* to = cur->destination();
-        HPhi* phi = LookupPhi(to);
-        LOperand* hint = to;
-        if (phi != NULL) {
-          // This is a phi resolving move.
-          if (!phi->block()->IsLoopHeader()) {
-            hint = LiveRangeFor(phi->id())->current_hint_operand();
-          }
-        } else {
-          if (to->IsUnallocated()) {
-            if (live->Contains(LUnallocated::cast(to)->virtual_register())) {
-              Define(curr_position, to, from);
-              live->Remove(LUnallocated::cast(to)->virtual_register());
-            } else {
-              cur->Eliminate();
-              continue;
-            }
-          } else {
-            Define(curr_position, to, from);
-          }
-        }
-        Use(block_start_position, curr_position, from, hint);
-        if (from->IsUnallocated()) {
-          live->Add(LUnallocated::cast(from)->virtual_register());
-        }
-      }
-    } else {
-      DCHECK(!IsGapAt(index));
-      LInstruction* instr = InstructionAt(index);
-
-      if (instr != NULL) {
-        LOperand* output = instr->Output();
-        if (output != NULL) {
-          if (output->IsUnallocated()) {
-            live->Remove(LUnallocated::cast(output)->virtual_register());
-          }
-          Define(curr_position, output, NULL);
-        }
-
-        if (instr->ClobbersRegisters()) {
-          for (int i = 0; i < Register::kNumRegisters; ++i) {
-            if (Register::from_code(i).IsAllocatable()) {
-              if (output == NULL || !output->IsRegister() ||
-                  output->index() != i) {
-                LiveRange* range = FixedLiveRangeFor(i);
-                range->AddUseInterval(curr_position,
-                                      curr_position.InstructionEnd(), zone());
-              }
-            }
-          }
-        }
-
-        if (instr->ClobbersDoubleRegisters(isolate())) {
-          for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
-            if (DoubleRegister::from_code(i).IsAllocatable()) {
-              if (output == NULL || !output->IsDoubleRegister() ||
-                  output->index() != i) {
-                LiveRange* range = FixedDoubleLiveRangeFor(i);
-                range->AddUseInterval(curr_position,
-                                      curr_position.InstructionEnd(), zone());
-              }
-            }
-          }
-        }
-
-        for (UseIterator it(instr); !it.Done(); it.Advance()) {
-          LOperand* input = it.Current();
-
-          LifetimePosition use_pos;
-          if (input->IsUnallocated() &&
-              LUnallocated::cast(input)->IsUsedAtStart()) {
-            use_pos = curr_position;
-          } else {
-            use_pos = curr_position.InstructionEnd();
-          }
-
-          Use(block_start_position, use_pos, input, NULL);
-          if (input->IsUnallocated()) {
-            live->Add(LUnallocated::cast(input)->virtual_register());
-          }
-        }
-
-        for (TempIterator it(instr); !it.Done(); it.Advance()) {
-          LOperand* temp = it.Current();
-          if (instr->ClobbersTemps()) {
-            if (temp->IsRegister()) continue;
-            if (temp->IsUnallocated()) {
-              LUnallocated* temp_unalloc = LUnallocated::cast(temp);
-              if (temp_unalloc->HasFixedPolicy()) {
-                continue;
-              }
-            }
-          }
-          Use(block_start_position, curr_position.InstructionEnd(), temp, NULL);
-          Define(curr_position, temp, NULL);
-
-          if (temp->IsUnallocated()) {
-            LUnallocated* temp_unalloc = LUnallocated::cast(temp);
-            if (temp_unalloc->HasDoubleRegisterPolicy()) {
-              double_artificial_registers_.Add(
-                  temp_unalloc->virtual_register() - first_artificial_register_,
-                  zone());
-            }
-          }
-        }
-      }
-    }
-
-    index = index - 1;
-  }
-}
-
-
-void LAllocator::ResolvePhis(HBasicBlock* block) {
-  const ZoneList<HPhi*>* phis = block->phis();
-  for (int i = 0; i < phis->length(); ++i) {
-    HPhi* phi = phis->at(i);
-    LUnallocated* phi_operand =
-        new (chunk()->zone()) LUnallocated(LUnallocated::NONE);
-    phi_operand->set_virtual_register(phi->id());
-    for (int j = 0; j < phi->OperandCount(); ++j) {
-      HValue* op = phi->OperandAt(j);
-      LOperand* operand = NULL;
-      if (op->IsConstant() && op->EmitAtUses()) {
-        HConstant* constant = HConstant::cast(op);
-        operand = chunk_->DefineConstantOperand(constant);
-      } else {
-        DCHECK(!op->EmitAtUses());
-        LUnallocated* unalloc =
-            new(chunk()->zone()) LUnallocated(LUnallocated::ANY);
-        unalloc->set_virtual_register(op->id());
-        operand = unalloc;
-      }
-      HBasicBlock* cur_block = block->predecessors()->at(j);
-      // The gap move must be added without any special processing as in
-      // the AddConstraintsGapMove.
-      chunk_->AddGapMove(cur_block->last_instruction_index() - 1,
-                         operand,
-                         phi_operand);
-
-      // We are going to insert a move before the branch instruction.
-      // Some branch instructions (e.g. loops' back edges)
-      // can potentially cause a GC so they have a pointer map.
-      // By inserting a move we essentially create a copy of a
-      // value which is invisible to PopulatePointerMaps(), because we store
-      // it into a location different from the operand of a live range
-      // covering a branch instruction.
-      // Thus we need to manually record a pointer.
-      LInstruction* branch =
-          InstructionAt(cur_block->last_instruction_index());
-      if (branch->HasPointerMap()) {
-        if (phi->representation().IsTagged() && !phi->type().IsSmi()) {
-          branch->pointer_map()->RecordPointer(phi_operand, chunk()->zone());
-        } else if (!phi->representation().IsDouble()) {
-          branch->pointer_map()->RecordUntagged(phi_operand, chunk()->zone());
-        }
-      }
-    }
-
-    LiveRange* live_range = LiveRangeFor(phi->id());
-    LLabel* label = chunk_->GetLabel(phi->block()->block_id());
-    label->GetOrCreateParallelMove(LGap::START, chunk()->zone())->
-        AddMove(phi_operand, live_range->GetSpillOperand(), chunk()->zone());
-    live_range->SetSpillStartIndex(phi->block()->first_instruction_index());
-  }
-}
-
-
-bool LAllocator::Allocate(LChunk* chunk) {
-  DCHECK(chunk_ == NULL);
-  chunk_ = static_cast<LPlatformChunk*>(chunk);
-  assigned_registers_ =
-      new (chunk->zone()) BitVector(Register::kNumRegisters, chunk->zone());
-  assigned_double_registers_ = new (chunk->zone())
-      BitVector(DoubleRegister::kMaxNumRegisters, chunk->zone());
-  MeetRegisterConstraints();
-  if (!AllocationOk()) return false;
-  ResolvePhis();
-  BuildLiveRanges();
-  AllocateGeneralRegisters();
-  if (!AllocationOk()) return false;
-  AllocateDoubleRegisters();
-  if (!AllocationOk()) return false;
-  PopulatePointerMaps();
-  ConnectRanges();
-  ResolveControlFlow();
-  return true;
-}
-
-
-void LAllocator::MeetRegisterConstraints() {
-  LAllocatorPhase phase("L_Register constraints", this);
-  const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
-  for (int i = 0; i < blocks->length(); ++i) {
-    HBasicBlock* block = blocks->at(i);
-    MeetRegisterConstraints(block);
-    if (!AllocationOk()) return;
-  }
-}
-
-
-void LAllocator::ResolvePhis() {
-  LAllocatorPhase phase("L_Resolve phis", this);
-
-  // Process the blocks in reverse order.
-  const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
-  for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) {
-    HBasicBlock* block = blocks->at(block_id);
-    ResolvePhis(block);
-  }
-}
-
-
-void LAllocator::ResolveControlFlow(LiveRange* range,
-                                    HBasicBlock* block,
-                                    HBasicBlock* pred) {
-  LifetimePosition pred_end =
-      LifetimePosition::FromInstructionIndex(pred->last_instruction_index());
-  LifetimePosition cur_start =
-      LifetimePosition::FromInstructionIndex(block->first_instruction_index());
-  LiveRange* pred_cover = NULL;
-  LiveRange* cur_cover = NULL;
-  LiveRange* cur_range = range;
-  while (cur_range != NULL && (cur_cover == NULL || pred_cover == NULL)) {
-    if (cur_range->CanCover(cur_start)) {
-      DCHECK(cur_cover == NULL);
-      cur_cover = cur_range;
-    }
-    if (cur_range->CanCover(pred_end)) {
-      DCHECK(pred_cover == NULL);
-      pred_cover = cur_range;
-    }
-    cur_range = cur_range->next();
-  }
-
-  if (cur_cover->IsSpilled()) return;
-  DCHECK(pred_cover != NULL && cur_cover != NULL);
-  if (pred_cover != cur_cover) {
-    LOperand* pred_op = pred_cover->CreateAssignedOperand(chunk()->zone());
-    LOperand* cur_op = cur_cover->CreateAssignedOperand(chunk()->zone());
-    if (!pred_op->Equals(cur_op)) {
-      LGap* gap = NULL;
-      if (block->predecessors()->length() == 1) {
-        gap = GapAt(block->first_instruction_index());
-      } else {
-        DCHECK(pred->end()->SecondSuccessor() == NULL);
-        gap = GetLastGap(pred);
-
-        // We are going to insert a move before the branch instruction.
-        // Some branch instructions (e.g. loops' back edges)
-        // can potentially cause a GC so they have a pointer map.
-        // By inserting a move we essentially create a copy of a
-        // value which is invisible to PopulatePointerMaps(), because we store
-        // it into a location different from the operand of a live range
-        // covering a branch instruction.
-        // Thus we need to manually record a pointer.
-        LInstruction* branch = InstructionAt(pred->last_instruction_index());
-        if (branch->HasPointerMap()) {
-          if (HasTaggedValue(range->id())) {
-            branch->pointer_map()->RecordPointer(cur_op, chunk()->zone());
-          } else if (!cur_op->IsDoubleStackSlot() &&
-                     !cur_op->IsDoubleRegister()) {
-            branch->pointer_map()->RemovePointer(cur_op);
-          }
-        }
-      }
-      gap->GetOrCreateParallelMove(
-          LGap::START, chunk()->zone())->AddMove(pred_op, cur_op,
-                                                 chunk()->zone());
-    }
-  }
-}
-
-
-LParallelMove* LAllocator::GetConnectingParallelMove(LifetimePosition pos) {
-  int index = pos.InstructionIndex();
-  if (IsGapAt(index)) {
-    LGap* gap = GapAt(index);
-    return gap->GetOrCreateParallelMove(
-        pos.IsInstructionStart() ? LGap::START : LGap::END, chunk()->zone());
-  }
-  int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1);
-  return GapAt(gap_pos)->GetOrCreateParallelMove(
-      (gap_pos < index) ? LGap::AFTER : LGap::BEFORE, chunk()->zone());
-}
-
-
-HBasicBlock* LAllocator::GetBlock(LifetimePosition pos) {
-  LGap* gap = GapAt(chunk_->NearestGapPos(pos.InstructionIndex()));
-  return gap->block();
-}
-
-
-void LAllocator::ConnectRanges() {
-  LAllocatorPhase phase("L_Connect ranges", this);
-  for (int i = 0; i < live_ranges()->length(); ++i) {
-    LiveRange* first_range = live_ranges()->at(i);
-    if (first_range == NULL || first_range->parent() != NULL) continue;
-
-    LiveRange* second_range = first_range->next();
-    while (second_range != NULL) {
-      LifetimePosition pos = second_range->Start();
-
-      if (!second_range->IsSpilled()) {
-        // Add gap move if the two live ranges touch and there is no block
-        // boundary.
-        if (first_range->End().Value() == pos.Value()) {
-          bool should_insert = true;
-          if (IsBlockBoundary(pos)) {
-            should_insert = CanEagerlyResolveControlFlow(GetBlock(pos));
-          }
-          if (should_insert) {
-            LParallelMove* move = GetConnectingParallelMove(pos);
-            LOperand* prev_operand = first_range->CreateAssignedOperand(
-                chunk()->zone());
-            LOperand* cur_operand = second_range->CreateAssignedOperand(
-                chunk()->zone());
-            move->AddMove(prev_operand, cur_operand,
-                          chunk()->zone());
-          }
-        }
-      }
-
-      first_range = second_range;
-      second_range = second_range->next();
-    }
-  }
-}
-
-
-bool LAllocator::CanEagerlyResolveControlFlow(HBasicBlock* block) const {
-  if (block->predecessors()->length() != 1) return false;
-  return block->predecessors()->first()->block_id() == block->block_id() - 1;
-}
-
-
-void LAllocator::ResolveControlFlow() {
-  LAllocatorPhase phase("L_Resolve control flow", this);
-  const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
-  for (int block_id = 1; block_id < blocks->length(); ++block_id) {
-    HBasicBlock* block = blocks->at(block_id);
-    if (CanEagerlyResolveControlFlow(block)) continue;
-    BitVector* live = live_in_sets_[block->block_id()];
-    BitVector::Iterator iterator(live);
-    while (!iterator.Done()) {
-      int operand_index = iterator.Current();
-      for (int i = 0; i < block->predecessors()->length(); ++i) {
-        HBasicBlock* cur = block->predecessors()->at(i);
-        LiveRange* cur_range = LiveRangeFor(operand_index);
-        ResolveControlFlow(cur_range, block, cur);
-      }
-      iterator.Advance();
-    }
-  }
-}
-
-
-void LAllocator::BuildLiveRanges() {
-  LAllocatorPhase phase("L_Build live ranges", this);
-  InitializeLivenessAnalysis();
-  // Process the blocks in reverse order.
-  const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
-  for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) {
-    HBasicBlock* block = blocks->at(block_id);
-    BitVector* live = ComputeLiveOut(block);
-    // Initially consider all live_out values live for the entire block. We
-    // will shorten these intervals if necessary.
-    AddInitialIntervals(block, live);
-
-    // Process the instructions in reverse order, generating and killing
-    // live values.
-    ProcessInstructions(block, live);
-    // All phi output operands are killed by this block.
-    const ZoneList<HPhi*>* phis = block->phis();
-    for (int i = 0; i < phis->length(); ++i) {
-      // The live range interval already ends at the first instruction of the
-      // block.
-      HPhi* phi = phis->at(i);
-      live->Remove(phi->id());
-
-      LOperand* hint = NULL;
-      LOperand* phi_operand = NULL;
-      LGap* gap = GetLastGap(phi->block()->predecessors()->at(0));
-      LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
-                                                         chunk()->zone());
-      for (int j = 0; j < move->move_operands()->length(); ++j) {
-        LOperand* to = move->move_operands()->at(j).destination();
-        if (to->IsUnallocated() &&
-            LUnallocated::cast(to)->virtual_register() == phi->id()) {
-          hint = move->move_operands()->at(j).source();
-          phi_operand = to;
-          break;
-        }
-      }
-      DCHECK(hint != NULL);
-
-      LifetimePosition block_start = LifetimePosition::FromInstructionIndex(
-              block->first_instruction_index());
-      Define(block_start, phi_operand, hint);
-    }
-
-    // Now live is live_in for this block except not including values live
-    // out on backward successor edges.
-    live_in_sets_[block_id] = live;
-
-    // If this block is a loop header go back and patch up the necessary
-    // predecessor blocks.
-    if (block->IsLoopHeader()) {
-      // TODO(kmillikin): Need to be able to get the last block of the loop
-      // in the loop information. Add a live range stretching from the first
-      // loop instruction to the last for each value live on entry to the
-      // header.
-      HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
-      BitVector::Iterator iterator(live);
-      LifetimePosition start = LifetimePosition::FromInstructionIndex(
-          block->first_instruction_index());
-      LifetimePosition end = LifetimePosition::FromInstructionIndex(
-          back_edge->last_instruction_index()).NextInstruction();
-      while (!iterator.Done()) {
-        int operand_index = iterator.Current();
-        LiveRange* range = LiveRangeFor(operand_index);
-        range->EnsureInterval(start, end, zone());
-        iterator.Advance();
-      }
-
-      for (int i = block->block_id() + 1; i <= back_edge->block_id(); ++i) {
-        live_in_sets_[i]->Union(*live);
-      }
-    }
-
-#ifdef DEBUG
-    if (block_id == 0) {
-      BitVector::Iterator iterator(live);
-      bool found = false;
-      while (!iterator.Done()) {
-        found = true;
-        int operand_index = iterator.Current();
-        {
-          AllowHandleDereference allow_deref;
-          PrintF("Function: %s\n", chunk_->info()->GetDebugName().get());
-        }
-        PrintF("Value %d used before first definition!\n", operand_index);
-        LiveRange* range = LiveRangeFor(operand_index);
-        PrintF("First use is at %d\n", range->first_pos()->pos().Value());
-        iterator.Advance();
-      }
-      DCHECK(!found);
-    }
-#endif
-  }
-
-  for (int i = 0; i < live_ranges_.length(); ++i) {
-    if (live_ranges_[i] != NULL) {
-      live_ranges_[i]->kind_ = RequiredRegisterKind(live_ranges_[i]->id());
-    }
-  }
-}
-
-
-bool LAllocator::SafePointsAreInOrder() const {
-  const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
-  int safe_point = 0;
-  for (int i = 0; i < pointer_maps->length(); ++i) {
-    LPointerMap* map = pointer_maps->at(i);
-    if (safe_point > map->lithium_position()) return false;
-    safe_point = map->lithium_position();
-  }
-  return true;
-}
-
-
-void LAllocator::PopulatePointerMaps() {
-  LAllocatorPhase phase("L_Populate pointer maps", this);
-  const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
-
-  DCHECK(SafePointsAreInOrder());
-
-  // Iterate over all safe point positions and record a pointer
-  // for all spilled live ranges at this point.
-  int first_safe_point_index = 0;
-  int last_range_start = 0;
-  for (int range_idx = 0; range_idx < live_ranges()->length(); ++range_idx) {
-    LiveRange* range = live_ranges()->at(range_idx);
-    if (range == NULL) continue;
-    // Iterate over the first parts of multi-part live ranges.
-    if (range->parent() != NULL) continue;
-    // Skip non-pointer values.
-    if (!HasTaggedValue(range->id())) continue;
-    // Skip empty live ranges.
-    if (range->IsEmpty()) continue;
-
-    // Find the extent of the range and its children.
-    int start = range->Start().InstructionIndex();
-    int end = 0;
-    for (LiveRange* cur = range; cur != NULL; cur = cur->next()) {
-      LifetimePosition this_end = cur->End();
-      if (this_end.InstructionIndex() > end) end = this_end.InstructionIndex();
-      DCHECK(cur->Start().InstructionIndex() >= start);
-    }
-
-    // Most of the ranges are in order, but not all.  Keep an eye on when
-    // they step backwards and reset the first_safe_point_index so we don't
-    // miss any safe points.
-    if (start < last_range_start) {
-      first_safe_point_index = 0;
-    }
-    last_range_start = start;
-
-    // Step across all the safe points that are before the start of this range,
-    // recording how far we step in order to save doing this for the next range.
-    while (first_safe_point_index < pointer_maps->length()) {
-      LPointerMap* map = pointer_maps->at(first_safe_point_index);
-      int safe_point = map->lithium_position();
-      if (safe_point >= start) break;
-      first_safe_point_index++;
-    }
-
-    // Step through the safe points to see whether they are in the range.
-    for (int safe_point_index = first_safe_point_index;
-         safe_point_index < pointer_maps->length();
-         ++safe_point_index) {
-      LPointerMap* map = pointer_maps->at(safe_point_index);
-      int safe_point = map->lithium_position();
-
-      // The safe points are sorted so we can stop searching here.
-      if (safe_point - 1 > end) break;
-
-      // Advance to the next active range that covers the current
-      // safe point position.
-      LifetimePosition safe_point_pos =
-          LifetimePosition::FromInstructionIndex(safe_point);
-      LiveRange* cur = range;
-      while (cur != NULL && !cur->Covers(safe_point_pos)) {
-        cur = cur->next();
-      }
-      if (cur == NULL) continue;
-
-      // Check if the live range is spilled and the safe point is after
-      // the spill position.
-      if (range->HasAllocatedSpillOperand() &&
-          safe_point >= range->spill_start_index()) {
-        TraceAlloc("Pointer for range %d (spilled at %d) at safe point %d\n",
-                   range->id(), range->spill_start_index(), safe_point);
-        map->RecordPointer(range->GetSpillOperand(), chunk()->zone());
-      }
-
-      if (!cur->IsSpilled()) {
-        TraceAlloc("Pointer in register for range %d (start at %d) "
-                   "at safe point %d\n",
-                   cur->id(), cur->Start().Value(), safe_point);
-        LOperand* operand = cur->CreateAssignedOperand(chunk()->zone());
-        DCHECK(!operand->IsStackSlot());
-        map->RecordPointer(operand, chunk()->zone());
-      }
-    }
-  }
-}
-
-
-void LAllocator::AllocateGeneralRegisters() {
-  LAllocatorPhase phase("L_Allocate general registers", this);
-  num_registers_ =
-      RegisterConfiguration::ArchDefault()->num_allocatable_general_registers();
-  allocatable_register_codes_ =
-      RegisterConfiguration::ArchDefault()->allocatable_general_codes();
-  mode_ = GENERAL_REGISTERS;
-  AllocateRegisters();
-}
-
-
-void LAllocator::AllocateDoubleRegisters() {
-  LAllocatorPhase phase("L_Allocate double registers", this);
-  num_registers_ =
-      RegisterConfiguration::ArchDefault()->num_allocatable_double_registers();
-  allocatable_register_codes_ =
-      RegisterConfiguration::ArchDefault()->allocatable_double_codes();
-  mode_ = DOUBLE_REGISTERS;
-  AllocateRegisters();
-}
-
-
-void LAllocator::AllocateRegisters() {
-  DCHECK(unhandled_live_ranges_.is_empty());
-
-  for (int i = 0; i < live_ranges_.length(); ++i) {
-    if (live_ranges_[i] != NULL) {
-      if (live_ranges_[i]->Kind() == mode_) {
-        AddToUnhandledUnsorted(live_ranges_[i]);
-      }
-    }
-  }
-  SortUnhandled();
-  DCHECK(UnhandledIsSorted());
-
-  DCHECK(reusable_slots_.is_empty());
-  DCHECK(active_live_ranges_.is_empty());
-  DCHECK(inactive_live_ranges_.is_empty());
-
-  if (mode_ == DOUBLE_REGISTERS) {
-    for (int i = 0; i < fixed_double_live_ranges_.length(); ++i) {
-      LiveRange* current = fixed_double_live_ranges_.at(i);
-      if (current != NULL) {
-        AddToInactive(current);
-      }
-    }
-  } else {
-    DCHECK(mode_ == GENERAL_REGISTERS);
-    for (int i = 0; i < fixed_live_ranges_.length(); ++i) {
-      LiveRange* current = fixed_live_ranges_.at(i);
-      if (current != NULL) {
-        AddToInactive(current);
-      }
-    }
-  }
-
-  while (!unhandled_live_ranges_.is_empty()) {
-    DCHECK(UnhandledIsSorted());
-    LiveRange* current = unhandled_live_ranges_.RemoveLast();
-    DCHECK(UnhandledIsSorted());
-    LifetimePosition position = current->Start();
-#ifdef DEBUG
-    allocation_finger_ = position;
-#endif
-    TraceAlloc("Processing interval %d start=%d\n",
-               current->id(),
-               position.Value());
-
-    if (current->HasAllocatedSpillOperand()) {
-      TraceAlloc("Live range %d already has a spill operand\n", current->id());
-      LifetimePosition next_pos = position;
-      if (IsGapAt(next_pos.InstructionIndex())) {
-        next_pos = next_pos.NextInstruction();
-      }
-      UsePosition* pos = current->NextUsePositionRegisterIsBeneficial(next_pos);
-      // If the range already has a spill operand and it doesn't need a
-      // register immediately, split it and spill the first part of the range.
-      if (pos == NULL) {
-        Spill(current);
-        continue;
-      } else if (pos->pos().Value() >
-                 current->Start().NextInstruction().Value()) {
-        // Do not spill live range eagerly if use position that can benefit from
-        // the register is too close to the start of live range.
-        SpillBetween(current, current->Start(), pos->pos());
-        if (!AllocationOk()) return;
-        DCHECK(UnhandledIsSorted());
-        continue;
-      }
-    }
-
-    for (int i = 0; i < active_live_ranges_.length(); ++i) {
-      LiveRange* cur_active = active_live_ranges_.at(i);
-      if (cur_active->End().Value() <= position.Value()) {
-        ActiveToHandled(cur_active);
-        --i;  // The live range was removed from the list of active live ranges.
-      } else if (!cur_active->Covers(position)) {
-        ActiveToInactive(cur_active);
-        --i;  // The live range was removed from the list of active live ranges.
-      }
-    }
-
-    for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
-      LiveRange* cur_inactive = inactive_live_ranges_.at(i);
-      if (cur_inactive->End().Value() <= position.Value()) {
-        InactiveToHandled(cur_inactive);
-        --i;  // Live range was removed from the list of inactive live ranges.
-      } else if (cur_inactive->Covers(position)) {
-        InactiveToActive(cur_inactive);
-        --i;  // Live range was removed from the list of inactive live ranges.
-      }
-    }
-
-    DCHECK(!current->HasRegisterAssigned() && !current->IsSpilled());
-
-    bool result = TryAllocateFreeReg(current);
-    if (!AllocationOk()) return;
-
-    if (!result) AllocateBlockedReg(current);
-    if (!AllocationOk()) return;
-
-    if (current->HasRegisterAssigned()) {
-      AddToActive(current);
-    }
-  }
-
-  reusable_slots_.Rewind(0);
-  active_live_ranges_.Rewind(0);
-  inactive_live_ranges_.Rewind(0);
-}
-
-
-const char* LAllocator::RegisterName(int allocation_index) {
-  if (mode_ == GENERAL_REGISTERS) {
-    return Register::from_code(allocation_index).ToString();
-  } else {
-    return DoubleRegister::from_code(allocation_index).ToString();
-  }
-}
-
-
-void LAllocator::TraceAlloc(const char* msg, ...) {
-  if (FLAG_trace_alloc) {
-    va_list arguments;
-    va_start(arguments, msg);
-    base::OS::VPrint(msg, arguments);
-    va_end(arguments);
-  }
-}
-
-
-bool LAllocator::HasTaggedValue(int virtual_register) const {
-  HValue* value = graph_->LookupValue(virtual_register);
-  if (value == NULL) return false;
-  return value->representation().IsTagged() && !value->type().IsSmi();
-}
-
-
-RegisterKind LAllocator::RequiredRegisterKind(int virtual_register) const {
-  if (virtual_register < first_artificial_register_) {
-    HValue* value = graph_->LookupValue(virtual_register);
-    if (value != NULL && value->representation().IsDouble()) {
-      return DOUBLE_REGISTERS;
-    }
-  } else if (double_artificial_registers_.Contains(
-      virtual_register - first_artificial_register_)) {
-    return DOUBLE_REGISTERS;
-  }
-
-  return GENERAL_REGISTERS;
-}
-
-
-void LAllocator::AddToActive(LiveRange* range) {
-  TraceAlloc("Add live range %d to active\n", range->id());
-  active_live_ranges_.Add(range, zone());
-}
-
-
-void LAllocator::AddToInactive(LiveRange* range) {
-  TraceAlloc("Add live range %d to inactive\n", range->id());
-  inactive_live_ranges_.Add(range, zone());
-}
-
-
-void LAllocator::AddToUnhandledSorted(LiveRange* range) {
-  if (range == NULL || range->IsEmpty()) return;
-  DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled());
-  DCHECK(allocation_finger_.Value() <= range->Start().Value());
-  for (int i = unhandled_live_ranges_.length() - 1; i >= 0; --i) {
-    LiveRange* cur_range = unhandled_live_ranges_.at(i);
-    if (range->ShouldBeAllocatedBefore(cur_range)) {
-      TraceAlloc("Add live range %d to unhandled at %d\n", range->id(), i + 1);
-      unhandled_live_ranges_.InsertAt(i + 1, range, zone());
-      DCHECK(UnhandledIsSorted());
-      return;
-    }
-  }
-  TraceAlloc("Add live range %d to unhandled at start\n", range->id());
-  unhandled_live_ranges_.InsertAt(0, range, zone());
-  DCHECK(UnhandledIsSorted());
-}
-
-
-void LAllocator::AddToUnhandledUnsorted(LiveRange* range) {
-  if (range == NULL || range->IsEmpty()) return;
-  DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled());
-  TraceAlloc("Add live range %d to unhandled unsorted at end\n", range->id());
-  unhandled_live_ranges_.Add(range, zone());
-}
-
-
-static int UnhandledSortHelper(LiveRange* const* a, LiveRange* const* b) {
-  DCHECK(!(*a)->ShouldBeAllocatedBefore(*b) ||
-         !(*b)->ShouldBeAllocatedBefore(*a));
-  if ((*a)->ShouldBeAllocatedBefore(*b)) return 1;
-  if ((*b)->ShouldBeAllocatedBefore(*a)) return -1;
-  return (*a)->id() - (*b)->id();
-}
-
-
-// Sort the unhandled live ranges so that the ranges to be processed first are
-// at the end of the array list.  This is convenient for the register allocation
-// algorithm because it is efficient to remove elements from the end.
-void LAllocator::SortUnhandled() {
-  TraceAlloc("Sort unhandled\n");
-  unhandled_live_ranges_.Sort(&UnhandledSortHelper);
-}
-
-
-bool LAllocator::UnhandledIsSorted() {
-  int len = unhandled_live_ranges_.length();
-  for (int i = 1; i < len; i++) {
-    LiveRange* a = unhandled_live_ranges_.at(i - 1);
-    LiveRange* b = unhandled_live_ranges_.at(i);
-    if (a->Start().Value() < b->Start().Value()) return false;
-  }
-  return true;
-}
-
-
-void LAllocator::FreeSpillSlot(LiveRange* range) {
-  // Check that we are the last range.
-  if (range->next() != NULL) return;
-
-  if (!range->TopLevel()->HasAllocatedSpillOperand()) return;
-
-  int index = range->TopLevel()->GetSpillOperand()->index();
-  if (index >= 0) {
-    reusable_slots_.Add(range, zone());
-  }
-}
-
-
-LOperand* LAllocator::TryReuseSpillSlot(LiveRange* range) {
-  if (reusable_slots_.is_empty()) return NULL;
-  if (reusable_slots_.first()->End().Value() >
-      range->TopLevel()->Start().Value()) {
-    return NULL;
-  }
-  LOperand* result = reusable_slots_.first()->TopLevel()->GetSpillOperand();
-  reusable_slots_.Remove(0);
-  return result;
-}
-
-
-void LAllocator::ActiveToHandled(LiveRange* range) {
-  DCHECK(active_live_ranges_.Contains(range));
-  active_live_ranges_.RemoveElement(range);
-  TraceAlloc("Moving live range %d from active to handled\n", range->id());
-  FreeSpillSlot(range);
-}
-
-
-void LAllocator::ActiveToInactive(LiveRange* range) {
-  DCHECK(active_live_ranges_.Contains(range));
-  active_live_ranges_.RemoveElement(range);
-  inactive_live_ranges_.Add(range, zone());
-  TraceAlloc("Moving live range %d from active to inactive\n", range->id());
-}
-
-
-void LAllocator::InactiveToHandled(LiveRange* range) {
-  DCHECK(inactive_live_ranges_.Contains(range));
-  inactive_live_ranges_.RemoveElement(range);
-  TraceAlloc("Moving live range %d from inactive to handled\n", range->id());
-  FreeSpillSlot(range);
-}
-
-
-void LAllocator::InactiveToActive(LiveRange* range) {
-  DCHECK(inactive_live_ranges_.Contains(range));
-  inactive_live_ranges_.RemoveElement(range);
-  active_live_ranges_.Add(range, zone());
-  TraceAlloc("Moving live range %d from inactive to active\n", range->id());
-}
-
-
-bool LAllocator::TryAllocateFreeReg(LiveRange* current) {
-  DCHECK(DoubleRegister::kMaxNumRegisters >= Register::kNumRegisters);
-
-  LifetimePosition free_until_pos[DoubleRegister::kMaxNumRegisters];
-
-  for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
-    free_until_pos[i] = LifetimePosition::MaxPosition();
-  }
-
-  for (int i = 0; i < active_live_ranges_.length(); ++i) {
-    LiveRange* cur_active = active_live_ranges_.at(i);
-    free_until_pos[cur_active->assigned_register()] =
-        LifetimePosition::FromInstructionIndex(0);
-  }
-
-  for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
-    LiveRange* cur_inactive = inactive_live_ranges_.at(i);
-    DCHECK(cur_inactive->End().Value() > current->Start().Value());
-    LifetimePosition next_intersection =
-        cur_inactive->FirstIntersection(current);
-    if (!next_intersection.IsValid()) continue;
-    int cur_reg = cur_inactive->assigned_register();
-    free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection);
-  }
-
-  LOperand* hint = current->FirstHint();
-  if (hint != NULL && (hint->IsRegister() || hint->IsDoubleRegister())) {
-    int register_index = hint->index();
-    TraceAlloc(
-        "Found reg hint %s (free until [%d) for live range %d (end %d[).\n",
-        RegisterName(register_index),
-        free_until_pos[register_index].Value(),
-        current->id(),
-        current->End().Value());
-
-    // The desired register is free until the end of the current live range.
-    if (free_until_pos[register_index].Value() >= current->End().Value()) {
-      TraceAlloc("Assigning preferred reg %s to live range %d\n",
-                 RegisterName(register_index),
-                 current->id());
-      SetLiveRangeAssignedRegister(current, register_index);
-      return true;
-    }
-  }
-
-  // Find the register which stays free for the longest time.
-  int reg = allocatable_register_codes_[0];
-  for (int i = 1; i < RegisterCount(); ++i) {
-    int code = allocatable_register_codes_[i];
-    if (free_until_pos[code].Value() > free_until_pos[reg].Value()) {
-      reg = code;
-    }
-  }
-
-  LifetimePosition pos = free_until_pos[reg];
-
-  if (pos.Value() <= current->Start().Value()) {
-    // All registers are blocked.
-    return false;
-  }
-
-  if (pos.Value() < current->End().Value()) {
-    // Register reg is available at the range start but becomes blocked before
-    // the range end. Split current at position where it becomes blocked.
-    LiveRange* tail = SplitRangeAt(current, pos);
-    if (!AllocationOk()) return false;
-    AddToUnhandledSorted(tail);
-  }
-
-
-  // Register reg is available at the range start and is free until
-  // the range end.
-  DCHECK(pos.Value() >= current->End().Value());
-  TraceAlloc("Assigning free reg %s to live range %d\n",
-             RegisterName(reg),
-             current->id());
-  SetLiveRangeAssignedRegister(current, reg);
-
-  return true;
-}
-
-
-void LAllocator::AllocateBlockedReg(LiveRange* current) {
-  UsePosition* register_use = current->NextRegisterPosition(current->Start());
-  if (register_use == NULL) {
-    // There is no use in the current live range that requires a register.
-    // We can just spill it.
-    Spill(current);
-    return;
-  }
-
-
-  LifetimePosition use_pos[DoubleRegister::kMaxNumRegisters];
-  LifetimePosition block_pos[DoubleRegister::kMaxNumRegisters];
-
-  for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
-    use_pos[i] = block_pos[i] = LifetimePosition::MaxPosition();
-  }
-
-  for (int i = 0; i < active_live_ranges_.length(); ++i) {
-    LiveRange* range = active_live_ranges_[i];
-    int cur_reg = range->assigned_register();
-    if (range->IsFixed() || !range->CanBeSpilled(current->Start())) {
-      block_pos[cur_reg] = use_pos[cur_reg] =
-          LifetimePosition::FromInstructionIndex(0);
-    } else {
-      UsePosition* next_use = range->NextUsePositionRegisterIsBeneficial(
-          current->Start());
-      if (next_use == NULL) {
-        use_pos[cur_reg] = range->End();
-      } else {
-        use_pos[cur_reg] = next_use->pos();
-      }
-    }
-  }
-
-  for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
-    LiveRange* range = inactive_live_ranges_.at(i);
-    DCHECK(range->End().Value() > current->Start().Value());
-    LifetimePosition next_intersection = range->FirstIntersection(current);
-    if (!next_intersection.IsValid()) continue;
-    int cur_reg = range->assigned_register();
-    if (range->IsFixed()) {
-      block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection);
-      use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]);
-    } else {
-      use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection);
-    }
-  }
-
-  int reg = allocatable_register_codes_[0];
-  for (int i = 1; i < RegisterCount(); ++i) {
-    int code = allocatable_register_codes_[i];
-    if (use_pos[code].Value() > use_pos[reg].Value()) {
-      reg = code;
-    }
-  }
-
-  LifetimePosition pos = use_pos[reg];
-
-  if (pos.Value() < register_use->pos().Value()) {
-    // All registers are blocked before the first use that requires a register.
-    // Spill starting part of live range up to that use.
-    SpillBetween(current, current->Start(), register_use->pos());
-    return;
-  }
-
-  if (block_pos[reg].Value() < current->End().Value()) {
-    // Register becomes blocked before the current range end. Split before that
-    // position.
-    LiveRange* tail = SplitBetween(current,
-                                   current->Start(),
-                                   block_pos[reg].InstructionStart());
-    if (!AllocationOk()) return;
-    AddToUnhandledSorted(tail);
-  }
-
-  // Register reg is not blocked for the whole range.
-  DCHECK(block_pos[reg].Value() >= current->End().Value());
-  TraceAlloc("Assigning blocked reg %s to live range %d\n",
-             RegisterName(reg),
-             current->id());
-  SetLiveRangeAssignedRegister(current, reg);
-
-  // This register was not free. Thus we need to find and spill
-  // parts of active and inactive live regions that use the same register
-  // at the same lifetime positions as current.
-  SplitAndSpillIntersecting(current);
-}
-
-
-LifetimePosition LAllocator::FindOptimalSpillingPos(LiveRange* range,
-                                                    LifetimePosition pos) {
-  HBasicBlock* block = GetBlock(pos.InstructionStart());
-  HBasicBlock* loop_header =
-      block->IsLoopHeader() ? block : block->parent_loop_header();
-
-  if (loop_header == NULL) return pos;
-
-  UsePosition* prev_use =
-    range->PreviousUsePositionRegisterIsBeneficial(pos);
-
-  while (loop_header != NULL) {
-    // We are going to spill live range inside the loop.
-    // If possible try to move spilling position backwards to loop header.
-    // This will reduce number of memory moves on the back edge.
-    LifetimePosition loop_start = LifetimePosition::FromInstructionIndex(
-        loop_header->first_instruction_index());
-
-    if (range->Covers(loop_start)) {
-      if (prev_use == NULL || prev_use->pos().Value() < loop_start.Value()) {
-        // No register beneficial use inside the loop before the pos.
-        pos = loop_start;
-      }
-    }
-
-    // Try hoisting out to an outer loop.
-    loop_header = loop_header->parent_loop_header();
-  }
-
-  return pos;
-}
-
-
-void LAllocator::SplitAndSpillIntersecting(LiveRange* current) {
-  DCHECK(current->HasRegisterAssigned());
-  int reg = current->assigned_register();
-  LifetimePosition split_pos = current->Start();
-  for (int i = 0; i < active_live_ranges_.length(); ++i) {
-    LiveRange* range = active_live_ranges_[i];
-    if (range->assigned_register() == reg) {
-      UsePosition* next_pos = range->NextRegisterPosition(current->Start());
-      LifetimePosition spill_pos = FindOptimalSpillingPos(range, split_pos);
-      if (next_pos == NULL) {
-        SpillAfter(range, spill_pos);
-      } else {
-        // When spilling between spill_pos and next_pos ensure that the range
-        // remains spilled at least until the start of the current live range.
-        // This guarantees that we will not introduce new unhandled ranges that
-        // start before the current range as this violates allocation invariant
-        // and will lead to an inconsistent state of active and inactive
-        // live-ranges: ranges are allocated in order of their start positions,
-        // ranges are retired from active/inactive when the start of the
-        // current live-range is larger than their end.
-        SpillBetweenUntil(range, spill_pos, current->Start(), next_pos->pos());
-      }
-      if (!AllocationOk()) return;
-      ActiveToHandled(range);
-      --i;
-    }
-  }
-
-  for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
-    LiveRange* range = inactive_live_ranges_[i];
-    DCHECK(range->End().Value() > current->Start().Value());
-    if (range->assigned_register() == reg && !range->IsFixed()) {
-      LifetimePosition next_intersection = range->FirstIntersection(current);
-      if (next_intersection.IsValid()) {
-        UsePosition* next_pos = range->NextRegisterPosition(current->Start());
-        if (next_pos == NULL) {
-          SpillAfter(range, split_pos);
-        } else {
-          next_intersection = Min(next_intersection, next_pos->pos());
-          SpillBetween(range, split_pos, next_intersection);
-        }
-        if (!AllocationOk()) return;
-        InactiveToHandled(range);
-        --i;
-      }
-    }
-  }
-}
-
-
-bool LAllocator::IsBlockBoundary(LifetimePosition pos) {
-  return pos.IsInstructionStart() &&
-      InstructionAt(pos.InstructionIndex())->IsLabel();
-}
-
-
-LiveRange* LAllocator::SplitRangeAt(LiveRange* range, LifetimePosition pos) {
-  DCHECK(!range->IsFixed());
-  TraceAlloc("Splitting live range %d at %d\n", range->id(), pos.Value());
-
-  if (pos.Value() <= range->Start().Value()) return range;
-
-  // We can't properly connect liveranges if split occured at the end
-  // of control instruction.
-  DCHECK(pos.IsInstructionStart() ||
-         !chunk_->instructions()->at(pos.InstructionIndex())->IsControl());
-
-  int vreg = GetVirtualRegister();
-  if (!AllocationOk()) return NULL;
-  LiveRange* result = LiveRangeFor(vreg);
-  range->SplitAt(pos, result, zone());
-  return result;
-}
-
-
-LiveRange* LAllocator::SplitBetween(LiveRange* range,
-                                    LifetimePosition start,
-                                    LifetimePosition end) {
-  DCHECK(!range->IsFixed());
-  TraceAlloc("Splitting live range %d in position between [%d, %d]\n",
-             range->id(),
-             start.Value(),
-             end.Value());
-
-  LifetimePosition split_pos = FindOptimalSplitPos(start, end);
-  DCHECK(split_pos.Value() >= start.Value());
-  return SplitRangeAt(range, split_pos);
-}
-
-
-LifetimePosition LAllocator::FindOptimalSplitPos(LifetimePosition start,
-                                                 LifetimePosition end) {
-  int start_instr = start.InstructionIndex();
-  int end_instr = end.InstructionIndex();
-  DCHECK(start_instr <= end_instr);
-
-  // We have no choice
-  if (start_instr == end_instr) return end;
-
-  HBasicBlock* start_block = GetBlock(start);
-  HBasicBlock* end_block = GetBlock(end);
-
-  if (end_block == start_block) {
-    // The interval is split in the same basic block. Split at the latest
-    // possible position.
-    return end;
-  }
-
-  HBasicBlock* block = end_block;
-  // Find header of outermost loop.
-  while (block->parent_loop_header() != NULL &&
-      block->parent_loop_header()->block_id() > start_block->block_id()) {
-    block = block->parent_loop_header();
-  }
-
-  // We did not find any suitable outer loop. Split at the latest possible
-  // position unless end_block is a loop header itself.
-  if (block == end_block && !end_block->IsLoopHeader()) return end;
-
-  return LifetimePosition::FromInstructionIndex(
-      block->first_instruction_index());
-}
-
-
-void LAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) {
-  LiveRange* second_part = SplitRangeAt(range, pos);
-  if (!AllocationOk()) return;
-  Spill(second_part);
-}
-
-
-void LAllocator::SpillBetween(LiveRange* range,
-                              LifetimePosition start,
-                              LifetimePosition end) {
-  SpillBetweenUntil(range, start, start, end);
-}
-
-
-void LAllocator::SpillBetweenUntil(LiveRange* range,
-                                   LifetimePosition start,
-                                   LifetimePosition until,
-                                   LifetimePosition end) {
-  CHECK(start.Value() < end.Value());
-  LiveRange* second_part = SplitRangeAt(range, start);
-  if (!AllocationOk()) return;
-
-  if (second_part->Start().Value() < end.Value()) {
-    // The split result intersects with [start, end[.
-    // Split it at position between ]start+1, end[, spill the middle part
-    // and put the rest to unhandled.
-    LiveRange* third_part = SplitBetween(
-        second_part,
-        Max(second_part->Start().InstructionEnd(), until),
-        end.PrevInstruction().InstructionEnd());
-    if (!AllocationOk()) return;
-
-    DCHECK(third_part != second_part);
-
-    Spill(second_part);
-    AddToUnhandledSorted(third_part);
-  } else {
-    // The split result does not intersect with [start, end[.
-    // Nothing to spill. Just put it to unhandled as whole.
-    AddToUnhandledSorted(second_part);
-  }
-}
-
-
-void LAllocator::Spill(LiveRange* range) {
-  DCHECK(!range->IsSpilled());
-  TraceAlloc("Spilling live range %d\n", range->id());
-  LiveRange* first = range->TopLevel();
-
-  if (!first->HasAllocatedSpillOperand()) {
-    LOperand* op = TryReuseSpillSlot(range);
-    if (op == NULL) op = chunk_->GetNextSpillSlot(range->Kind());
-    first->SetSpillOperand(op);
-  }
-  range->MakeSpilled(chunk()->zone());
-}
-
-
-int LAllocator::RegisterCount() const {
-  return num_registers_;
-}
-
-
-#ifdef DEBUG
-
-
-void LAllocator::Verify() const {
-  for (int i = 0; i < live_ranges()->length(); ++i) {
-    LiveRange* current = live_ranges()->at(i);
-    if (current != NULL) current->Verify();
-  }
-}
-
-
-#endif
-
-
-LAllocatorPhase::LAllocatorPhase(const char* name, LAllocator* allocator)
-    : CompilationPhase(name, allocator->graph()->info()),
-      allocator_(allocator) {
-  if (FLAG_hydrogen_stats) {
-    allocator_zone_start_allocation_size_ =
-        allocator->zone()->allocation_size();
-  }
-}
-
-
-LAllocatorPhase::~LAllocatorPhase() {
-  if (FLAG_hydrogen_stats) {
-    size_t size = allocator_->zone()->allocation_size() -
-                  allocator_zone_start_allocation_size_;
-    isolate()->GetHStatistics()->SaveTiming(name(), base::TimeDelta(), size);
-  }
-
-  if (ShouldProduceTraceOutput()) {
-    isolate()->GetHTracer()->TraceLithium(name(), allocator_->chunk());
-    isolate()->GetHTracer()->TraceLiveRanges(name(), allocator_);
-  }
-
-#ifdef DEBUG
-  if (allocator_ != NULL) allocator_->Verify();
-#endif
-}
-
-
-}  // namespace internal
-}  // namespace v8