[turbofan]: delay ssa deconstruction in register allocator

src/compiler/register-allocator.h

 // 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.
 
 #ifndef V8_REGISTER_ALLOCATOR_H_
 #define V8_REGISTER_ALLOCATOR_H_
 
 #include "src/compiler/instruction.h"
 #include "src/zone-containers.h"
 
@@ skipping 323 matching lines @@
   const ZoneVector<LiveRange*>& fixed_double_live_ranges() const {
     return fixed_double_live_ranges_;
   }
   InstructionSequence* code() const { return code_; }
   // This zone is for datastructures only needed during register allocation.
   Zone* local_zone() const { return local_zone_; }
 
   // Phase 1 : insert moves to account for fixed register operands.
   void MeetRegisterConstraints();
 
-  // Phase 2: deconstruct SSA by inserting moves in successors and the headers
-  // of blocks containing phis.
-  void ResolvePhis();
-
-  // Phase 3: compute liveness of all virtual register.
+  // Phase 2: compute liveness of all virtual register.
   void BuildLiveRanges();
   bool ExistsUseWithoutDefinition();
 
-  // Phase 4: compute register assignments.
+  // Phase 3: compute register assignments.
   void AllocateGeneralRegisters();
   void AllocateDoubleRegisters();
 
-  // Phase 5: compute values for pointer maps.
+  // Phase 4: compute values for pointer maps.
   void PopulatePointerMaps();  // TODO(titzer): rename to PopulateReferenceMaps.
 
-  // Phase 6: reconnect split ranges with moves.
+  // Phase 5: reconnect split ranges with moves.
   void ConnectRanges();
 
-  // Phase 7: insert moves to connect ranges across basic blocks.
+  // Phase 6: insert moves to connect ranges across basic blocks.
   void ResolveControlFlow();
 
  private:
   int GetVirtualRegister() {
     int vreg = code()->NextVirtualRegister();
     if (vreg >= UnallocatedOperand::kMaxVirtualRegisters) {
       allocation_ok_ = false;
       // Maintain the invariant that we return something below the maximum.
       return 0;
     }
@@ skipping 27 matching lines @@
   BitVector* ComputeLiveOut(const InstructionBlock* block);
   void AddInitialIntervals(const InstructionBlock* block, BitVector* live_out);
   bool IsOutputRegisterOf(Instruction* instr, int index);
   bool IsOutputDoubleRegisterOf(Instruction* instr, int index);
   void ProcessInstructions(const InstructionBlock* block, BitVector* live);
   void MeetRegisterConstraints(const InstructionBlock* block);
   void MeetConstraintsBetween(Instruction* first, Instruction* second,
                               int gap_index);
   void MeetRegisterConstraintsForLastInstructionInBlock(
       const InstructionBlock* block);
-  void ResolvePhis(const InstructionBlock* block);
+  void ProcessPhis(const InstructionBlock* block);
 
   // Helper methods for building intervals.
   InstructionOperand* AllocateFixed(UnallocatedOperand* operand, int pos,
                                     bool is_tagged);
   LiveRange* LiveRangeFor(InstructionOperand* operand);
   void Define(LifetimePosition position, InstructionOperand* operand,
               InstructionOperand* hint);
   void Use(LifetimePosition block_start, LifetimePosition position,
            InstructionOperand* operand, InstructionOperand* hint);
   void AddConstraintsGapMove(int index, InstructionOperand* from,
@@ skipping 127 matching lines @@
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(RegisterAllocator);
 };
 
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_REGISTER_ALLOCATOR_H_