Type handling for special cases and optimization

src/types.cc

Index: src/types.cc
diff --git a/src/types.cc b/src/types.cc
index b8febc2a149ad4e7e488a8cfc4e6a59f6c896da6..1275deacb744e7b2f60485e6c0deaa9005f1fc59 100644
--- a/src/types.cc
+++ b/src/types.cc
@@ -131,6 +131,7 @@ int Type::LubBitset() {
         if (value->IsUndefined()) return kUndefined;
         if (value->IsNull()) return kNull;
         if (value->IsTrue() || value->IsFalse()) return kBoolean;
+        if (value->IsTheHole()) return kAny;
       }
     }
     switch (map->instance_type()) {
@@ -200,6 +201,10 @@ int Type::LubBitset() {
         // We ought to find a cleaner solution for compiling stubs parameterised
         // over type or class variables, esp ones with bounds...
         return kDetectable;
+      case DECLARED_ACCESSOR_INFO_TYPE:
+      case EXECUTABLE_ACCESSOR_INFO_TYPE:
+      case ACCESSOR_PAIR_TYPE:
+        return kInternal;
       default:
         UNREACHABLE();
         return kNone;
@@ -222,7 +227,7 @@ int Type::GlbBitset() {
 
 
 // Check this <= that.
-bool Type::Is(Type* that) {
+bool Type::IsSlowCase(Type* that) {
   // Fast path for bitsets.
   if (that->is_bitset()) {
     return (this->LubBitset() | that->as_bitset()) == that->as_bitset();