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

src/interpreter/bytecode-peephole-optimizer.cc

 // Copyright 2016 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.
 
 #include "src/interpreter/bytecode-peephole-optimizer.h"
 
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
 namespace v8 {
@@ skipping 123 matching lines @@
     BytecodeNode* const current) {
   DCHECK_EQ(last->bytecode(), Bytecode::kLdaZero);
   BytecodeNode node(new_bytecode, 0, current->operand(0), current->operand(1),
                     current->source_info());
   if (last->source_info().is_valid()) {
     node.set_source_info(last->source_info());
   }
   return node;
 }
 
-BytecodeNode TransformEqualityWithNullOrUndefined(Bytecode new_bytecode,
-                                                  BytecodeNode* const last,
-                                                  BytecodeNode* const current) {
-  DCHECK((last->bytecode() == Bytecode::kLdaNull) ||
-         (last->bytecode() == Bytecode::kLdaUndefined));
-  DCHECK((current->bytecode() == Bytecode::kTestEqual) ||
-         (current->bytecode() == Bytecode::kTestEqualStrict));
-  BytecodeNode node(new_bytecode, current->operand(0), current->source_info());
-  if (last->source_info().is_valid()) {
-    node.set_source_info(last->source_info());
-  }
-  return node;
-}
-
 }  // namespace
 
 void BytecodePeepholeOptimizer::DefaultAction(
     BytecodeNode* const node, const PeepholeActionAndData* action_data) {
   DCHECK(LastIsValid());
   DCHECK(!Bytecodes::IsJump(node->bytecode()));
 
   next_stage()->Write(last());
   SetLast(node);
 }
@@ skipping 93 matching lines @@
   if (!node->source_info().is_valid() || !last()->source_info().is_valid()) {
     // Fused last and current into current.
     BytecodeNode new_node(TransformLdaZeroBinaryOpToBinaryOpWithZero(
         action_data->bytecode, last(), node));
     SetLast(&new_node);
   } else {
     DefaultAction(node);
   }
 }
 
-void BytecodePeepholeOptimizer::TransformEqualityWithNullOrUndefinedAction(
-    BytecodeNode* const node, const PeepholeActionAndData* action_data) {
-  DCHECK(LastIsValid());
-  DCHECK(!Bytecodes::IsJump(node->bytecode()));
-  // Fused last and current into current.
-  BytecodeNode new_node(TransformEqualityWithNullOrUndefined(
-      action_data->bytecode, last(), node));
-  SetLast(&new_node);
-}
-
 void BytecodePeepholeOptimizer::DefaultJumpAction(
     BytecodeNode* const node, const PeepholeActionAndData* action_data) {
   DCHECK(LastIsValid());
   DCHECK(Bytecodes::IsJump(node->bytecode()));
 
   next_stage()->Write(last());
   InvalidateLast();
 }
 
 void BytecodePeepholeOptimizer::UpdateLastJumpAction(
@@ skipping 42 matching lines @@
 #undef CASE
     default:
       UNREACHABLE();
       break;
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8