Mark null and undefined as undetectable, and use it to handle abstract equality comparison in the g…

src/crankshaft/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/crankshaft/ia32/lithium-codegen-ia32.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5106 matching lines @@
     __ CmpObjectType(input, SYMBOL_TYPE, input);
     final_branch_condition = equal;
 
   } else if (String::Equals(type_name, factory()->boolean_string())) {
     __ cmp(input, factory()->true_value());
     __ j(equal, true_label, true_distance);
     __ cmp(input, factory()->false_value());
     final_branch_condition = equal;
 
   } else if (String::Equals(type_name, factory()->undefined_string())) {
-    __ cmp(input, factory()->undefined_value());
-    __ j(equal, true_label, true_distance);
+    __ cmp(input, factory()->null_value());
+    __ j(equal, false_label, false_distance);
     __ JumpIfSmi(input, false_label, false_distance);
     // Check for undetectable objects => true.
     __ mov(input, FieldOperand(input, HeapObject::kMapOffset));
     __ test_b(FieldOperand(input, Map::kBitFieldOffset),
               1 << Map::kIsUndetectable);
     final_branch_condition = not_zero;
 
   } else if (String::Equals(type_name, factory()->function_string())) {
     __ JumpIfSmi(input, false_label, false_distance);
     // Check for callable and not undetectable objects => true.
@@ skipping 288 matching lines @@
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32