Introduce Type::IsCurrently

src/types.cc

Index: src/types.cc
diff --git a/src/types.cc b/src/types.cc
index 7c54d4fb27e7db94b06c1726a9e07678bc8ead80..485ba885187364ed2b99098865eec3197b2c47dc 100644
--- a/src/types.cc
+++ b/src/types.cc
@@ -244,7 +244,7 @@ int Type::GlbBitset() {
 
 
 // Most precise _current_ type of a value (usually its class).
-Type* Type::CurrentOf(Handle<i::Object> value) {
+Type* Type::OfCurrently(Handle<i::Object> value) {
   if (value->IsSmi()) return Smi();
   i::Map* map = i::HeapObject::cast(*value)->map();
   if (map->instance_type() == HEAP_NUMBER_TYPE ||
@@ -297,6 +297,14 @@ bool Type::SlowIs(Type* that) {
 }
 
 
+bool Type::IsCurrently(Type* that) {
+  return this->Is(that) ||
+      (this->is_constant() && that->is_class() &&
+       this->as_constant()->IsHeapObject() &&
+       i::HeapObject::cast(*this->as_constant())->map() == *that->as_class());
+}
+
+
 // Check this overlaps that.
 bool Type::Maybe(Type* that) {
   // Fast path for bitsets.