[turbofan] decouple register allocation from schedule and graph

src/compiler/register-allocator.cc

 // Copyright 2014 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/compiler/register-allocator.h"
 
-#include "src/compiler/generic-node-inl.h"
 #include "src/compiler/linkage.h"
 #include "src/hydrogen.h"
 #include "src/string-stream.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) {
   return a.Value() < b.Value() ? a : b;
@@ skipping 499 matching lines @@
 
 
 void RegisterAllocator::InitializeLivenessAnalysis() {
   // Initialize the live_in sets for each block to NULL.
   int block_count = code()->BasicBlockCount();
   live_in_sets_.Initialize(block_count, zone());
   live_in_sets_.AddBlock(NULL, block_count, zone());
 }
 
 
-BitVector* RegisterAllocator::ComputeLiveOut(BasicBlock* block) {
+BitVector* RegisterAllocator::ComputeLiveOut(const InstructionBlock* block) {
   // Compute live out for the given block, except not including backward
   // successor edges.
   BitVector* live_out =
       new (zone()) BitVector(code()->VirtualRegisterCount(), zone());
 
   // Process all successor blocks.
-  for (BasicBlock::Successors::iterator i = block->successors_begin();
-       i != block->successors_end(); ++i) {
+  for (auto succ : block->successors()) {
     // Add values live on entry to the successor. Note the successor's
     // live_in will not be computed yet for backwards edges.
-    BasicBlock* successor = *i;
-    BitVector* live_in = live_in_sets_[successor->rpo_number()];
+    BitVector* live_in = live_in_sets_[succ.ToSize()];
     if (live_in != NULL) live_out->Union(*live_in);
 
     // All phi input operands corresponding to this successor edge are live
     // out from this block.
-    size_t index = successor->PredecessorIndexOf(block);
+    const InstructionBlock* successor = code()->InstructionBlockAt(succ);
+    size_t index = successor->PredecessorIndexOf(block->rpo_number());
     DCHECK(index < successor->PredecessorCount());
-    for (BasicBlock::const_iterator j = successor->begin();
-         j != successor->end(); ++j) {
-      Node* phi = *j;
-      if (phi->opcode() != IrOpcode::kPhi) continue;
-      Node* input = phi->InputAt(static_cast<int>(index));
-      live_out->Add(code()->GetVirtualRegister(input));
+    for (auto phi : successor->phis()) {
+      live_out->Add(phi->operands()[index]);
     }
   }
   return live_out;
 }
 
 
-void RegisterAllocator::AddInitialIntervals(BasicBlock* block,
+void RegisterAllocator::AddInitialIntervals(const InstructionBlock* 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(
-      code()->first_instruction_index(block));
-  LifetimePosition end =
-      LifetimePosition::FromInstructionIndex(
-          code()->last_instruction_index(block)).NextInstruction();
+  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();
   }
 }
 
 
@@ skipping 67 matching lines @@
   }
   LiveRange* result = live_ranges_[index];
   if (result == NULL) {
     result = new (zone()) LiveRange(index, code_zone());
     live_ranges_[index] = result;
   }
   return result;
 }
 
 
-GapInstruction* RegisterAllocator::GetLastGap(BasicBlock* block) {
-  int last_instruction = code()->last_instruction_index(block);
+GapInstruction* RegisterAllocator::GetLastGap(const InstructionBlock* block) {
+  int last_instruction = block->last_instruction_index();
   return code()->GapAt(last_instruction - 1);
 }
 
 
 LiveRange* RegisterAllocator::LiveRangeFor(InstructionOperand* operand) {
   if (operand->IsUnallocated()) {
     return LiveRangeFor(UnallocatedOperand::cast(operand)->virtual_register());
   } else if (operand->IsRegister()) {
     return FixedLiveRangeFor(operand->index());
   } else if (operand->IsDoubleRegister()) {
@@ skipping 56 matching lines @@
           move->AddMove(cur.source(), to, code_zone());
           return;
         }
       }
     }
   }
   move->AddMove(from, to, code_zone());
 }
 
 
-void RegisterAllocator::MeetRegisterConstraints(BasicBlock* block) {
-  int start = code()->first_instruction_index(block);
-  int end = code()->last_instruction_index(block);
+void RegisterAllocator::MeetRegisterConstraints(const InstructionBlock* block) {
+  int start = block->first_instruction_index();
+  int end = block->last_instruction_index();
   DCHECK_NE(-1, start);
   for (int i = start; i <= end; ++i) {
     if (code()->IsGapAt(i)) {
       Instruction* instr = NULL;
       Instruction* 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;
     }
   }
 
   // Meet register constraints for the instruction in the end.
   if (!code()->IsGapAt(end)) {
     MeetRegisterConstraintsForLastInstructionInBlock(block);
   }
 }
 
 
 void RegisterAllocator::MeetRegisterConstraintsForLastInstructionInBlock(
-    BasicBlock* block) {
-  int end = code()->last_instruction_index(block);
+    const InstructionBlock* block) {
+  int end = block->last_instruction_index();
   Instruction* last_instruction = InstructionAt(end);
   for (size_t i = 0; i < last_instruction->OutputCount(); i++) {
     InstructionOperand* output_operand = last_instruction->OutputAt(i);
     DCHECK(!output_operand->IsConstant());
     UnallocatedOperand* output = UnallocatedOperand::cast(output_operand);
     int output_vreg = output->virtual_register();
     LiveRange* range = LiveRangeFor(output_vreg);
     bool assigned = false;
     if (output->HasFixedPolicy()) {
       AllocateFixed(output, -1, false);
       // This value is produced on the stack, we never need to spill it.
       if (output->IsStackSlot()) {
         range->SetSpillOperand(output);
         range->SetSpillStartIndex(end);
         assigned = true;
       }
 
-      for (BasicBlock::Successors::iterator succ = block->successors_begin();
-           succ != block->successors_end(); ++succ) {
-        DCHECK((*succ)->PredecessorCount() == 1);
-        int gap_index = code()->first_instruction_index(*succ) + 1;
+      for (auto succ : block->successors()) {
+        const InstructionBlock* successor = code()->InstructionBlockAt(succ);
+        DCHECK(successor->PredecessorCount() == 1);
+        int gap_index = successor->first_instruction_index() + 1;
         DCHECK(code()->IsGapAt(gap_index));
 
         // Create an unconstrained operand for the same virtual register
         // and insert a gap move from the fixed output to the operand.
         UnallocatedOperand* output_copy =
             new (code_zone()) UnallocatedOperand(UnallocatedOperand::ANY);
         output_copy->set_virtual_register(output_vreg);
 
         code()->AddGapMove(gap_index, output, output_copy);
       }
     }
 
     if (!assigned) {
-      for (BasicBlock::Successors::iterator succ = block->successors_begin();
-           succ != block->successors_end(); ++succ) {
-        DCHECK((*succ)->PredecessorCount() == 1);
-        int gap_index = code()->first_instruction_index(*succ) + 1;
+      for (auto succ : block->successors()) {
+        const InstructionBlock* successor = code()->InstructionBlockAt(succ);
+        DCHECK(successor->PredecessorCount() == 1);
+        int gap_index = successor->first_instruction_index() + 1;
         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.
         GapInstruction* gap = code()->GapAt(gap_index);
         ParallelMove* move =
             gap->GetOrCreateParallelMove(GapInstruction::BEFORE, code_zone());
         move->AddMove(output, range->GetSpillOperand(), code_zone());
@@ skipping 124 matching lines @@
 bool RegisterAllocator::IsOutputDoubleRegisterOf(Instruction* instr,
                                                  int index) {
   for (size_t i = 0; i < instr->OutputCount(); i++) {
     InstructionOperand* output = instr->OutputAt(i);
     if (output->IsDoubleRegister() && output->index() == index) return true;
   }
   return false;
 }
 
 
-void RegisterAllocator::ProcessInstructions(BasicBlock* block,
+void RegisterAllocator::ProcessInstructions(const InstructionBlock* block,
                                             BitVector* live) {
-  int block_start = code()->first_instruction_index(block);
+  int block_start = block->first_instruction_index();
 
   LifetimePosition block_start_position =
       LifetimePosition::FromInstructionIndex(block_start);
 
-  for (int index = code()->last_instruction_index(block); index >= block_start;
+  for (int index = block->last_instruction_index(); index >= block_start;
        index--) {
     LifetimePosition curr_position =
         LifetimePosition::FromInstructionIndex(index);
 
     Instruction* instr = InstructionAt(index);
     DCHECK(instr != NULL);
     if (instr->IsGapMoves()) {
       // Process the moves of the gap instruction, making their sources live.
       GapInstruction* gap = code()->GapAt(index);
 
@@ skipping 95 matching lines @@
           }
         }
         Use(block_start_position, curr_position.InstructionEnd(), temp, NULL);
         Define(curr_position, temp, NULL);
       }
     }
   }
 }
 
 
-void RegisterAllocator::ResolvePhis(BasicBlock* block) {
-  for (BasicBlock::const_iterator i = block->begin(); i != block->end(); ++i) {
-    Node* phi = *i;
-    if (phi->opcode() != IrOpcode::kPhi) continue;
-
+void RegisterAllocator::ResolvePhis(const InstructionBlock* block) {
+  for (auto phi : block->phis()) {
     UnallocatedOperand* phi_operand =
         new (code_zone()) UnallocatedOperand(UnallocatedOperand::NONE);
-    int phi_vreg = code()->GetVirtualRegister(phi);
+    int phi_vreg = phi->virtual_register();
     phi_operand->set_virtual_register(phi_vreg);
 
-    size_t j = 0;
-    Node::Inputs inputs = phi->inputs();
-    for (Node::Inputs::iterator iter(inputs.begin()); iter != inputs.end();
-         ++iter, ++j) {
-      Node* op = *iter;
-      // TODO(mstarzinger): Use a ValueInputIterator instead.
-      if (j >= block->PredecessorCount()) continue;
+    for (size_t i = 0; i < phi->operands().size(); ++i) {
       UnallocatedOperand* operand =
           new (code_zone()) UnallocatedOperand(UnallocatedOperand::ANY);
-      operand->set_virtual_register(code()->GetVirtualRegister(op));
-      BasicBlock* cur_block = block->PredecessorAt(j);
+      operand->set_virtual_register(phi->operands()[i]);
+      InstructionBlock* cur_block =
+          code()->InstructionBlockAt(block->predecessors()[i]);
       // The gap move must be added without any special processing as in
       // the AddConstraintsGapMove.
-      code()->AddGapMove(code()->last_instruction_index(cur_block) - 1, operand,
+      code()->AddGapMove(cur_block->last_instruction_index() - 1, operand,
                          phi_operand);
 
-      Instruction* branch =
-          InstructionAt(code()->last_instruction_index(cur_block));
+      Instruction* branch = InstructionAt(cur_block->last_instruction_index());
       DCHECK(!branch->HasPointerMap());
       USE(branch);
     }
 
     LiveRange* live_range = LiveRangeFor(phi_vreg);
     BlockStartInstruction* block_start =
-        code()->GetBlockStart(block->GetRpoNumber());
+        code()->GetBlockStart(block->rpo_number());
     block_start->GetOrCreateParallelMove(GapInstruction::START, code_zone())
         ->AddMove(phi_operand, live_range->GetSpillOperand(), code_zone());
-    live_range->SetSpillStartIndex(code()->first_instruction_index(block));
+    live_range->SetSpillStartIndex(block->first_instruction_index());
 
     // We use the phi-ness of some nodes in some later heuristics.
     live_range->set_is_phi(true);
     if (!block->IsLoopHeader()) {
       live_range->set_is_non_loop_phi(true);
     }
   }
 }
 
 
@@ skipping 15 matching lines @@
   ResolveControlFlow();
   code()->frame()->SetAllocatedRegisters(assigned_registers_);
   code()->frame()->SetAllocatedDoubleRegisters(assigned_double_registers_);
   return true;
 }
 
 
 void RegisterAllocator::MeetRegisterConstraints() {
   RegisterAllocatorPhase phase("L_Register constraints", this);
   for (int i = 0; i < code()->BasicBlockCount(); ++i) {
-    MeetRegisterConstraints(code()->BlockAt(i));
+    MeetRegisterConstraints(
+        code()->InstructionBlockAt(BasicBlock::RpoNumber::FromInt(i)));
     if (!AllocationOk()) return;
   }
 }
 
 
 void RegisterAllocator::ResolvePhis() {
   RegisterAllocatorPhase phase("L_Resolve phis", this);
 
   // Process the blocks in reverse order.
   for (int i = code()->BasicBlockCount() - 1; i >= 0; --i) {
-    ResolvePhis(code()->BlockAt(i));
+    ResolvePhis(code()->InstructionBlockAt(BasicBlock::RpoNumber::FromInt(i)));
   }
 }
 
 
-void RegisterAllocator::ResolveControlFlow(LiveRange* range, BasicBlock* block,
-                                           BasicBlock* pred) {
-  LifetimePosition pred_end = LifetimePosition::FromInstructionIndex(
-      code()->last_instruction_index(pred));
-  LifetimePosition cur_start = LifetimePosition::FromInstructionIndex(
-      code()->first_instruction_index(block));
+void RegisterAllocator::ResolveControlFlow(LiveRange* range,
+                                           const InstructionBlock* block,
+                                           const InstructionBlock* 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) {
     InstructionOperand* pred_op =
         pred_cover->CreateAssignedOperand(code_zone());
     InstructionOperand* cur_op = cur_cover->CreateAssignedOperand(code_zone());
     if (!pred_op->Equals(cur_op)) {
       GapInstruction* gap = NULL;
       if (block->PredecessorCount() == 1) {
-        gap = code()->GapAt(code()->first_instruction_index(block));
+        gap = code()->GapAt(block->first_instruction_index());
       } else {
         DCHECK(pred->SuccessorCount() == 1);
         gap = GetLastGap(pred);
 
-        Instruction* branch =
-            InstructionAt(code()->last_instruction_index(pred));
+        Instruction* branch = InstructionAt(pred->last_instruction_index());
         DCHECK(!branch->HasPointerMap());
         USE(branch);
       }
       gap->GetOrCreateParallelMove(GapInstruction::START, code_zone())
           ->AddMove(pred_op, cur_op, code_zone());
     }
   }
 }
 
 
 ParallelMove* RegisterAllocator::GetConnectingParallelMove(
     LifetimePosition pos) {
   int index = pos.InstructionIndex();
   if (code()->IsGapAt(index)) {
     GapInstruction* gap = code()->GapAt(index);
     return gap->GetOrCreateParallelMove(
         pos.IsInstructionStart() ? GapInstruction::START : GapInstruction::END,
         code_zone());
   }
   int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1);
   return code()->GapAt(gap_pos)->GetOrCreateParallelMove(
       (gap_pos < index) ? GapInstruction::AFTER : GapInstruction::BEFORE,
       code_zone());
 }
 
 
-BasicBlock* RegisterAllocator::GetBlock(LifetimePosition pos) {
-  return code()->GetBasicBlock(pos.InstructionIndex());
+const InstructionBlock* RegisterAllocator::GetInstructionBlock(
+    LifetimePosition pos) {
+  return code()->GetInstructionBlock(pos.InstructionIndex());
 }
 
 
 void RegisterAllocator::ConnectRanges() {
   RegisterAllocatorPhase 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));
+            should_insert =
+                CanEagerlyResolveControlFlow(GetInstructionBlock(pos));
           }
           if (should_insert) {
             ParallelMove* move = GetConnectingParallelMove(pos);
             InstructionOperand* prev_operand =
                 first_range->CreateAssignedOperand(code_zone());
             InstructionOperand* cur_operand =
                 second_range->CreateAssignedOperand(code_zone());
             move->AddMove(prev_operand, cur_operand, code_zone());
           }
         }
       }
 
       first_range = second_range;
       second_range = second_range->next();
     }
   }
 }
 
 
-bool RegisterAllocator::CanEagerlyResolveControlFlow(BasicBlock* block) const {
+bool RegisterAllocator::CanEagerlyResolveControlFlow(
+    const InstructionBlock* block) const {
   if (block->PredecessorCount() != 1) return false;
-  return block->PredecessorAt(0)->rpo_number() == block->rpo_number() - 1;
+  return block->predecessors()[0].IsNext(block->rpo_number());
 }
 
 
 void RegisterAllocator::ResolveControlFlow() {
   RegisterAllocatorPhase phase("L_Resolve control flow", this);
   for (int block_id = 1; block_id < code()->BasicBlockCount(); ++block_id) {
-    BasicBlock* block = code()->BlockAt(block_id);
+    const InstructionBlock* block =
+        code()->InstructionBlockAt(BasicBlock::RpoNumber::FromInt(block_id));
     if (CanEagerlyResolveControlFlow(block)) continue;
-    BitVector* live = live_in_sets_[block->rpo_number()];
+    BitVector* live = live_in_sets_[block->rpo_number().ToInt()];
     BitVector::Iterator iterator(live);
     while (!iterator.Done()) {
       int operand_index = iterator.Current();
-      for (BasicBlock::Predecessors::iterator i = block->predecessors_begin();
-           i != block->predecessors_end(); ++i) {
-        BasicBlock* cur = *i;
+      for (auto pred : block->predecessors()) {
+        const InstructionBlock* cur = code()->InstructionBlockAt(pred);
         LiveRange* cur_range = LiveRangeFor(operand_index);
         ResolveControlFlow(cur_range, block, cur);
       }
       iterator.Advance();
     }
   }
 }
 
 
 void RegisterAllocator::BuildLiveRanges() {
   RegisterAllocatorPhase phase("L_Build live ranges", this);
   InitializeLivenessAnalysis();
   // Process the blocks in reverse order.
   for (int block_id = code()->BasicBlockCount() - 1; block_id >= 0;
        --block_id) {
-    BasicBlock* block = code()->BlockAt(block_id);
+    const InstructionBlock* block =
+        code()->InstructionBlockAt(BasicBlock::RpoNumber::FromInt(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.
-    for (BasicBlock::const_iterator i = block->begin(); i != block->end();
-         ++i) {
-      Node* phi = *i;
-      if (phi->opcode() != IrOpcode::kPhi) continue;
-
+    for (auto phi : block->phis()) {
       // The live range interval already ends at the first instruction of the
       // block.
-      int phi_vreg = code()->GetVirtualRegister(phi);
+      int phi_vreg = phi->virtual_register();
       live->Remove(phi_vreg);
 
       InstructionOperand* hint = NULL;
       InstructionOperand* phi_operand = NULL;
-      GapInstruction* gap = GetLastGap(block->PredecessorAt(0));
+      GapInstruction* gap =
+          GetLastGap(code()->InstructionBlockAt(block->predecessors()[0]));
 
       // TODO(titzer): no need to create the parallel move if it doesn't exit.
       ParallelMove* move =
           gap->GetOrCreateParallelMove(GapInstruction::START, code_zone());
       for (int j = 0; j < move->move_operands()->length(); ++j) {
         InstructionOperand* to = move->move_operands()->at(j).destination();
         if (to->IsUnallocated() &&
             UnallocatedOperand::cast(to)->virtual_register() == phi_vreg) {
           hint = move->move_operands()->at(j).source();
           phi_operand = to;
           break;
         }
       }
       DCHECK(hint != NULL);
 
       LifetimePosition block_start = LifetimePosition::FromInstructionIndex(
-          code()->first_instruction_index(block));
+          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 (block->IsLoopHeader()) {
       // Add a live range stretching from the first loop instruction to the last
       // for each value live on entry to the header.
       BitVector::Iterator iterator(live);
       LifetimePosition start = LifetimePosition::FromInstructionIndex(
-          code()->first_instruction_index(block));
-      int end_index =
-          code()->last_instruction_index(code()->BlockAt(block->loop_end()));
+          block->first_instruction_index());
+      int end_index = code()
+                          ->InstructionBlockAt(block->loop_end())
+                          ->last_instruction_index();
       LifetimePosition end =
           LifetimePosition::FromInstructionIndex(end_index).NextInstruction();
       while (!iterator.Done()) {
         int operand_index = iterator.Current();
         LiveRange* range = LiveRangeFor(operand_index);
         range->EnsureInterval(start, end, zone());
         iterator.Advance();
       }
 
       // Insert all values into the live in sets of all blocks in the loop.
-      for (int i = block->rpo_number() + 1; i < block->loop_end(); ++i) {
+      for (int i = block->rpo_number().ToInt() + 1;
+           i < block->loop_end().ToInt(); ++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;
@@ skipping 587 matching lines @@
 
   // 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 RegisterAllocator::FindOptimalSpillingPos(
     LiveRange* range, LifetimePosition pos) {
-  BasicBlock* block = GetBlock(pos.InstructionStart());
-  BasicBlock* loop_header =
+  const InstructionBlock* block = GetInstructionBlock(pos.InstructionStart());
+  const InstructionBlock* loop_header =
       block->IsLoopHeader() ? block : code()->GetContainingLoop(block);
 
   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(
-        code()->first_instruction_index(loop_header));
+        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 = code()->GetContainingLoop(loop_header);
@@ skipping 94 matching lines @@
 
 LifetimePosition RegisterAllocator::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;
 
-  BasicBlock* start_block = GetBlock(start);
-  BasicBlock* end_block = GetBlock(end);
+  const InstructionBlock* start_block = GetInstructionBlock(start);
+  const InstructionBlock* end_block = GetInstructionBlock(end);
 
   if (end_block == start_block) {
     // The interval is split in the same basic block. Split at the latest
     // possible position.
     return end;
   }
 
-  BasicBlock* block = end_block;
+  const InstructionBlock* block = end_block;
   // Find header of outermost loop.
   // TODO(titzer): fix redundancy below.
   while (code()->GetContainingLoop(block) != NULL &&
-         code()->GetContainingLoop(block)->rpo_number() >
-             start_block->rpo_number()) {
+         code()->GetContainingLoop(block)->rpo_number().ToInt() >
+             start_block->rpo_number().ToInt()) {
     block = code()->GetContainingLoop(block);
   }
 
   // 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(
-      code()->first_instruction_index(block));
+      block->first_instruction_index());
 }
 
 
 void RegisterAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) {
   LiveRange* second_part = SplitRangeAt(range, pos);
   if (!AllocationOk()) return;
   Spill(second_part);
 }
 
 
@@ skipping 102 matching lines @@
                     allocator_zone_start_allocation_size_;
     isolate()->GetTStatistics()->SaveTiming(name(), base::TimeDelta(), size);
   }
 #ifdef DEBUG
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 }
 }
 }  // namespace v8::internal::compiler