[turbofan] The BytecodeGraphBuilder should never insert the empty frame state.

src/compiler/bytecode-graph-builder.h

 // Copyright 2015 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_COMPILER_BYTECODE_GRAPH_BUILDER_H_
 #define V8_COMPILER_BYTECODE_GRAPH_BUILDER_H_
 
 #include "src/compiler.h"
 #include "src/compiler/bytecode-branch-analysis.h"
 #include "src/compiler/js-graph.h"
@@ skipping 200 matching lines @@
   Zone* local_zone_;
   JSGraph* jsgraph_;
   Handle<BytecodeArray> bytecode_array_;
   Handle<HandlerTable> exception_handler_table_;
   Handle<TypeFeedbackVector> feedback_vector_;
   const FrameStateFunctionInfo* frame_state_function_info_;
   const interpreter::BytecodeArrayIterator* bytecode_iterator_;
   const BytecodeBranchAnalysis* branch_analysis_;
   Environment* environment_;
 
-  // Indicates whether deoptimization support is enabled for this compilation
-  // and whether valid frame states need to be attached to deoptimizing nodes.
-  bool deoptimization_enabled_;
-
   // Merge environments are snapshots of the environment at points where the
   // control flow merges. This models a forward data flow propagation of all
   // values from all predecessors of the merge in question.
   ZoneMap<int, Environment*> merge_environments_;
 
   // Exception handlers currently entered by the iteration.
   ZoneStack<ExceptionHandler> exception_handlers_;
   int current_exception_handler_;
 
   // Temporary storage for building node input lists.
   int input_buffer_size_;
   Node** input_buffer_;
 
   // Nodes representing values in the activation record.
   SetOncePointer<Node> function_context_;
   SetOncePointer<Node> function_closure_;
   SetOncePointer<Node> new_target_;
 
   // Control nodes that exit the function body.
   ZoneVector<Node*> exit_controls_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeGraphBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_BYTECODE_GRAPH_BUILDER_H_