[Interpreter] Optimize equality check with null/undefined with a check on the map.

test/unittests/interpreter/bytecode-array-builder-unittest.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecode-array-iterator.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-register-allocator.h"
@@ skipping 177 matching lines @@
   builder.CompareOperation(Token::Value::EQ, reg, 1)
       .CompareOperation(Token::Value::NE, reg, 2)
       .CompareOperation(Token::Value::EQ_STRICT, reg, 3)
       .CompareOperation(Token::Value::LT, reg, 4)
       .CompareOperation(Token::Value::GT, reg, 5)
       .CompareOperation(Token::Value::LTE, reg, 6)
       .CompareOperation(Token::Value::GTE, reg, 7)
       .CompareOperation(Token::Value::INSTANCEOF, reg, 8)
       .CompareOperation(Token::Value::IN, reg, 9);
 
+  // Emit peephole optimizations of equality with Null or Undefined.
+  builder.LoadUndefined()
+      .CompareOperation(Token::Value::EQ, reg, 1)
+      .LoadNull()
+      .CompareOperation(Token::Value::EQ, reg, 1);
+
   // Emit conversion operator invocations.
   builder.ConvertAccumulatorToNumber(reg)
       .ConvertAccumulatorToObject(reg)
       .ConvertAccumulatorToName(reg);
 
   // Short jumps with Imm8 operands
   {
     BytecodeLabel start, after_jump1, after_jump2, after_jump3, after_jump4;
     builder.Bind(&start)
         .Jump(&after_jump1)
@@ skipping 183 matching lines @@
     scorecard[Bytecodes::ToByte(Bytecode::kJumpIfTrue)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kJumpIfFalse)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kJumpIfTrueConstant)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kJumpIfFalseConstant)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kAddSmi)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kSubSmi)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kBitwiseAndSmi)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kBitwiseOrSmi)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kShiftLeftSmi)] = 1;
     scorecard[Bytecodes::ToByte(Bytecode::kShiftRightSmi)] = 1;
+    scorecard[Bytecodes::ToByte(Bytecode::kTestUndetectable)] = 1;
   }
 
   // Check return occurs at the end and only once in the BytecodeArray.
   CHECK_EQ(final_bytecode, Bytecode::kReturn);
   CHECK_EQ(scorecard[Bytecodes::ToByte(final_bytecode)], 1);
 
 #define CHECK_BYTECODE_PRESENT(Name, ...)                                \
   /* Check Bytecode is marked in scorecard, unless it's a debug break */ \
   if (!Bytecodes::IsDebugBreak(Bytecode::k##Name)) {                     \
     CHECK_GE(scorecard[Bytecodes::ToByte(Bytecode::k##Name)], 1);        \
@@ skipping 319 matching lines @@
     iterator.Advance();
   }
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kReturn);
   iterator.Advance();
   CHECK(iterator.done());
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8