Sped up hashCode by removing megamorphic call to _identityHashCode.

runtime/vm/jit_optimizer.cc

Index: runtime/vm/jit_optimizer.cc
diff --git a/runtime/vm/jit_optimizer.cc b/runtime/vm/jit_optimizer.cc
index 090ef67bd914b3dd95627445920c080bd01fa347..56074a2ebda735139356b64012f7fee09ba4206e 100644
--- a/runtime/vm/jit_optimizer.cc
+++ b/runtime/vm/jit_optimizer.cc
@@ -2332,6 +2332,12 @@ static bool TryExpandTestCidsResult(ZoneGrowableArray<intptr_t>* results,
 }
 
 
+// Tells whether the function of the call matches the core private name.
+static bool matches_core(InstanceCallInstr* call, const String& name) {
+  return call->function_name().raw() == Library::PrivateCoreLibName(name).raw();
+}
+
+
 // TODO(srdjan): Use ICData to check if always true or false.
 void JitOptimizer::ReplaceWithInstanceOf(InstanceCallInstr* call) {
   ASSERT(Token::IsTypeTestOperator(call->token_kind()));
@@ -2341,26 +2347,27 @@ void JitOptimizer::ReplaceWithInstanceOf(InstanceCallInstr* call) {
   bool negate = false;
   if (call->ArgumentCount() == 2) {
     type_args = flow_graph()->constant_null();
-    if (call->function_name().raw() ==
-        Library::PrivateCoreLibName(Symbols::_instanceOfNum()).raw()) {
-      type = Type::Number();
-    } else if (call->function_name().raw() ==
-        Library::PrivateCoreLibName(Symbols::_instanceOfInt()).raw()) {
-      type = Type::IntType();
-    } else if (call->function_name().raw() ==
-        Library::PrivateCoreLibName(Symbols::_instanceOfSmi()).raw()) {
-      type = Type::SmiType();
-    } else if (call->function_name().raw() ==
-        Library::PrivateCoreLibName(Symbols::_instanceOfDouble()).raw()) {
-      type = Type::Double();
-    } else if (call->function_name().raw() ==
-        Library::PrivateCoreLibName(Symbols::_instanceOfString()).raw()) {
-      type = Type::StringType();
+    if (matches_core(call, Symbols::_simpleInstanceOf())) {
+      type =
+          AbstractType::Cast(call->ArgumentAt(1)->AsConstant()->value()).raw();
+      negate = false;  // Just to be sure.
     } else {
-      UNIMPLEMENTED();
+      if (matches_core(call, Symbols::_instanceOfNum())) {
+        type = Type::Number();
+      } else if (matches_core(call, Symbols::_instanceOfInt())) {
+        type = Type::IntType();
+      } else if (matches_core(call, Symbols::_instanceOfSmi())) {
+        type = Type::SmiType();
+      } else if (matches_core(call, Symbols::_instanceOfDouble())) {
+        type = Type::Double();
+      } else if (matches_core(call, Symbols::_instanceOfString())) {
+        type = Type::StringType();
+      } else {
+        UNIMPLEMENTED();
+      }
+      negate = Bool::Cast(call->ArgumentAt(1)->OriginalDefinition()
+                          ->AsConstant()->value()).value();
     }
-    negate = Bool::Cast(call->ArgumentAt(1)->OriginalDefinition()
-        ->AsConstant()->value()).value();
   } else {
     type_args = call->ArgumentAt(1);
     type = AbstractType::Cast(call->ArgumentAt(2)->AsConstant()->value()).raw();