[turbofan] Avoid large deopt blocks

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/ostreams.h"
 #include "src/register-configuration.h"
@@ skipping 257 matching lines @@
   // For hinting only.
   void set_assigned_register(int register_code) {
     flags_ = AssignedRegisterField::update(flags_, register_code);
   }
 
   UsePositionHintType hint_type() const {
     return HintTypeField::decode(flags_);
   }
   bool HasHint() const;
   bool HintRegister(int* register_code) const;
+  void SetHint(UsePosition* use_pos);
   void ResolveHint(UsePosition* use_pos);
   bool IsResolved() const {
     return hint_type() != UsePositionHintType::kUnresolved;
   }
   static UsePositionHintType HintTypeForOperand(const InstructionOperand& op);
 
  private:
   typedef BitField<UsePositionType, 0, 2> TypeField;
   typedef BitField<UsePositionHintType, 2, 3> HintTypeField;
   typedef BitField<bool, 5, 1> RegisterBeneficialField;
@@ skipping 73 matching lines @@
   // Can this live range be spilled at this position.
   bool CanBeSpilled(LifetimePosition pos) const;
 
   // Splitting primitive used by both splitting and splintering members.
   // Performs the split, but does not link the resulting ranges.
   // The given position must follow the start of the range.
   // All uses following the given position will be moved from this
   // live range to the result live range.
   // The current range will terminate at position, while result will start from
   // position.
+  enum HintConnectionOption : bool {
+    DoNotConnectHints = false,
+    ConnectHints = true
+  };
   UsePosition* DetachAt(LifetimePosition position, LiveRange* result,
-                        Zone* zone);
+                        Zone* zone, HintConnectionOption connect_hints);
 
   // Detaches at position, and then links the resulting ranges. Returns the
   // child, which starts at position.
   LiveRange* SplitAt(LifetimePosition position, Zone* zone);
 
   // Returns nullptr when no register is hinted, otherwise sets register_index.
   UsePosition* FirstHintPosition(int* register_index) const;
   UsePosition* FirstHintPosition() const {
     int register_index;
     return FirstHintPosition(&register_index);
@@ skipping 785 matching lines @@
   RegisterAllocationData* const data_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveRangeConnector);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGISTER_ALLOCATOR_H_