Fix issue with -0 in Maps

src/objects.cc

 // Copyright 2013 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 <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
@@ skipping 780 matching lines @@
   if (heap_object->IsBoolean()) {
     return context->boolean_function()->initial_map();
   }
   return isolate->heap()->null_value()->map();
 }
 
 
 Object* Object::GetHash() {
   // The object is either a number, a name, an odd-ball,
   // a real JS object, or a Harmony proxy.
-  if (IsNumber()) {
-    uint32_t hash = std::isnan(Number())
-                        ? Smi::kMaxValue
-                        : ComputeLongHash(double_to_uint64(Number()));
+  if (IsSmi()) {
+    int num = Smi::cast(this)->value();
+    uint32_t hash = ComputeLongHash(double_to_uint64(static_cast<double>(num)));
+    return Smi::FromInt(hash & Smi::kMaxValue);
+  }
+  if (IsHeapNumber()) {
+    double num = HeapNumber::cast(this)->value();
+    if (std::isnan(num)) return Smi::FromInt(Smi::kMaxValue);
+    if (i::IsMinusZero(num)) num = 0;
+    uint32_t hash = ComputeLongHash(double_to_uint64(num));
     return Smi::FromInt(hash & Smi::kMaxValue);
   }
   if (IsName()) {
     uint32_t hash = Name::cast(this)->Hash();
     return Smi::FromInt(hash);
   }
   if (IsOddball()) {
     uint32_t hash = Oddball::cast(this)->to_string()->Hash();
     return Smi::FromInt(hash);
   }
@@ skipping 16510 matching lines @@
                                                CompilationInfo* info) {
   Handle<DependentCode> codes = DependentCode::InsertCompilationInfo(
       handle(cell->dependent_code(), info->isolate()),
       DependentCode::kPropertyCellChangedGroup, info->object_wrapper());
   if (*codes != cell->dependent_code()) cell->set_dependent_code(*codes);
   info->dependencies(DependentCode::kPropertyCellChangedGroup)->Add(
       cell, info->zone());
 }
 
 } }  // namespace v8::internal