With >= 64 non-string instance types, I removed an optimization

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 0a5215cb405164a8df8044ac986fb5dda4288796..fa8476d1d77aba785ed2ac4bd58a63dd2b754d41 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -221,9 +221,8 @@ bool Object::IsSpecFunction() {
 bool Object::IsInternalizedString() {
   if (!this->IsHeapObject()) return false;
   uint32_t type = HeapObject::cast(this)->map()->instance_type();
-  STATIC_ASSERT(kInternalizedTag != 0);
-  return (type & (kIsNotStringMask | kIsInternalizedMask)) ==
-      (kInternalizedTag | kStringTag);
+  STATIC_ASSERT(kNotInternalizedTag != 0);
+  return type < kNotInternalizedTag;

[Yang, 2013/07/19 09:52:18]

I kinda prefer the bit-masking way, since it doesn't implicitly assume anything.
Shouldn't be more expensive. Below as well. But this is your choice.

[mvstanton, 2013/07/19 11:07:42]

I wondered about that too, it's better to be symmetrical with the way we do the
test in assembly. I'll change to the bit test.

 }
 
 
@@ -319,9 +318,8 @@ StringShape::StringShape(InstanceType t)
 
 bool StringShape::IsInternalized() {
   ASSERT(valid());
-  STATIC_ASSERT(kInternalizedTag != 0);
-  return (type_ & (kIsNotStringMask | kIsInternalizedMask)) ==
-      (kInternalizedTag | kStringTag);
+  STATIC_ASSERT(kNotInternalizedTag != 0);
+  return type_ < kNotInternalizedTag;

[mvstanton, 2013/07/19 11:07:42]

I restored this one too.

 }