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

src/crankshaft/arm/lithium-codegen-arm.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.
 
 #include "src/crankshaft/arm/lithium-codegen-arm.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/arm/lithium-gap-resolver-arm.h"
@@ skipping 5223 matching lines @@
     __ CompareObjectType(input, scratch, no_reg, SYMBOL_TYPE);
     final_branch_condition = eq;
 
   } else if (String::Equals(type_name, factory->boolean_string())) {
     __ CompareRoot(input, Heap::kTrueValueRootIndex);
     __ b(eq, true_label);
     __ CompareRoot(input, Heap::kFalseValueRootIndex);
     final_branch_condition = eq;
 
   } else if (String::Equals(type_name, factory->undefined_string())) {
-    __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
-    __ b(eq, true_label);
+    __ CompareRoot(input, Heap::kNullValueRootIndex);
+    __ b(eq, false_label);
     __ JumpIfSmi(input, false_label);
     // Check for undetectable objects => true.
     __ ldr(scratch, FieldMemOperand(input, HeapObject::kMapOffset));
     __ ldrb(scratch, FieldMemOperand(scratch, Map::kBitFieldOffset));
     __ tst(scratch, Operand(1 << Map::kIsUndetectable));
     final_branch_condition = ne;
 
   } else if (String::Equals(type_name, factory->function_string())) {
     __ JumpIfSmi(input, false_label);
     __ ldr(scratch, FieldMemOperand(input, HeapObject::kMapOffset));
@@ skipping 298 matching lines @@
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8