[Interpreter] Optimize code of the form 'if (x === undefined)'.

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/bytecode-analysis.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-type-hint-lowering.h"
@@ skipping 194 matching lines @@
 
   // Helper function to compute call frequency from the recorded type
   // feedback.
   float ComputeCallFrequency(int slot_id) const;
 
   // Control flow plumbing.
   void BuildJump();
   void BuildJumpIf(Node* condition);
   void BuildJumpIfNot(Node* condition);
   void BuildJumpIfEqual(Node* comperand);
+  void BuildJumpIfNotEqual(Node* comperand);
   void BuildJumpIfTrue();
   void BuildJumpIfFalse();
   void BuildJumpIfToBooleanTrue();
   void BuildJumpIfToBooleanFalse();
   void BuildJumpIfNotHole();
   void BuildJumpIfJSReceiver();
 
   // Simulates control flow by forward-propagating environments.
   void MergeIntoSuccessorEnvironment(int target_offset);
   void BuildLoopHeaderEnvironment(int current_offset);
@@ skipping 138 matching lines @@
   static int const kBinaryOperationSmiHintIndex = 2;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeGraphBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_BYTECODE_GRAPH_BUILDER_H_