ARM64: Regenerate instead of spilling and restoring cheap lithium instructions.

src/lithium-allocator.h

 // 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.
 
 #ifndef V8_LITHIUM_ALLOCATOR_H_
 #define V8_LITHIUM_ALLOCATOR_H_
 
 #include "v8.h"
 
 #include "allocation.h"
@@ skipping 332 matching lines @@
                       LifetimePosition end,
                       Zone* zone);
   void AddUsePosition(LifetimePosition pos,
                       LOperand* operand,
                       LOperand* hint,
                       Zone* zone);
 
   // Shorten the most recently added interval by setting a new start.
   void ShortenTo(LifetimePosition start);
 
+  void set_parent_linstr(LInstruction* instr) {
+    parent_linstr_ = instr;
+    spill_operand_->set_parent_linstr(instr);
+  }
+  LInstruction* parent_linstr() const { return parent_linstr_; }
+
 #ifdef DEBUG
   // True if target overlaps an existing interval.
   bool HasOverlap(UseInterval* target) const;
   void Verify() const;
 #endif
 
  private:
   void ConvertOperands(Zone* zone);
   UseInterval* FirstSearchIntervalForPosition(LifetimePosition position) const;
   void AdvanceLastProcessedMarker(UseInterval* to_start_of,
                                   LifetimePosition but_not_past) const;
 
   int id_;
   bool spilled_;
   RegisterKind kind_;
   int assigned_register_;
   UseInterval* last_interval_;
   UseInterval* first_interval_;
   UsePosition* first_pos_;
   LiveRange* parent_;
   LiveRange* next_;
   // This is used as a cache, it doesn't affect correctness.
   mutable UseInterval* current_interval_;
   UsePosition* last_processed_use_;
   // This is used as a cache, it's invalid outside of BuildLiveRanges.
   LOperand* current_hint_operand_;
   LOperand* spill_operand_;
   int spill_start_index_;
+  LInstruction* parent_linstr_;
 
   friend class LAllocator;  // Assigns to kind_.
 };
 
 
 class LAllocator BASE_EMBEDDED {
  public:
   LAllocator(int first_virtual_register, HGraph* graph);
 
   static void TraceAlloc(const char* msg, ...);
@@ skipping 234 matching lines @@
   LAllocator* allocator_;
   unsigned allocator_zone_start_allocation_size_;
 
   DISALLOW_COPY_AND_ASSIGN(LAllocatorPhase);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_ALLOCATOR_H_