Use a better hash function in IdentityMap.

test/unittests/interpreter/constant-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/factory.h"
 #include "src/handles-inl.h"
 #include "src/interpreter/constant-array-builder.h"
 #include "src/isolate.h"
@@ skipping 15 matching lines @@
 
 STATIC_CONST_MEMBER_DEFINITION const size_t
     ConstantArrayBuilderTest::kMaxCapacity;
 STATIC_CONST_MEMBER_DEFINITION const size_t
     ConstantArrayBuilderTest::kLowCapacity;
 
 
 TEST_F(ConstantArrayBuilderTest, AllocateAllEntries) {
   ConstantArrayBuilder builder(isolate(), zone());
   for (size_t i = 0; i < kMaxCapacity; i++) {
-    Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
-    builder.Insert(object);
-    CHECK_EQ(builder.size(), i + 1);
-    CHECK(builder.At(i)->SameValue(*object));
+    builder.Insert(handle(Smi::FromInt(static_cast<int>(i)), isolate()));
   }
+  CHECK_EQ(builder.size(), kMaxCapacity);
   for (size_t i = 0; i < kMaxCapacity; i++) {
-    CHECK_EQ(Handle<Smi>::cast(builder.At(i))->value(), static_cast<double>(i));
+    CHECK_EQ(Handle<Smi>::cast(builder.At(i))->value(), i);
   }
 }
 
 
 TEST_F(ConstantArrayBuilderTest, AllocateEntriesWithIdx8Reservations) {
   for (size_t reserved = 1; reserved < kLowCapacity; reserved *= 3) {
     ConstantArrayBuilder builder(isolate(), zone());
     for (size_t i = 0; i < reserved; i++) {
       OperandSize operand_size = builder.CreateReservedEntry();
       CHECK(operand_size == OperandSize::kByte);
@@ skipping 162 matching lines @@
     Handle<Object> original = builder.At(kLowCapacity + i);
     CHECK(original->SameValue(*reference));
     Handle<Object> duplicate = builder.At(i);
     CHECK(duplicate->SameValue(*isolate()->factory()->the_hole_value()));
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8