Skip AssertAssignable in code generator if optimizer could establish that

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 1411 matching lines @@
 
   ConstantInstr* constant_type_args =
       instantiator_type_arguments()->definition()->AsConstant();
   if (constant_type_args != NULL &&
       !constant_type_args->value().IsNull() &&
       constant_type_args->value().IsTypeArguments()) {
     const TypeArguments& instantiator_type_args =
         TypeArguments::Cast(constant_type_args->value());
     const AbstractType& new_dst_type = AbstractType::Handle(
         dst_type().InstantiateFrom(instantiator_type_args, NULL));
+    // If dst_type is instantiated to dynamic or Object, skip the test.
+    if (!new_dst_type.IsMalformed() && !new_dst_type.IsMalbounded() &&
+        (new_dst_type.IsDynamicType() || new_dst_type.IsObjectType())) {
+      return value()->definition();
+    }
     set_dst_type(AbstractType::ZoneHandle(new_dst_type.Canonicalize()));
+    if (FLAG_eliminate_type_checks &&
+        value()->Type()->IsAssignableTo(dst_type())) {
+      return value()->definition();
+    }
     ConstantInstr* null_constant = flow_graph->constant_null();
     instantiator_type_arguments()->BindTo(null_constant);
   }
   return this;
 }
 
 
 Definition* BoxDoubleInstr::Canonicalize(FlowGraph* flow_graph) {
   if (input_use_list() == NULL) {
     // Environments can accomodate any representation. No need to box.
@@ skipping 1250 matching lines @@
       return kCosRuntimeEntry;
     default:
       UNREACHABLE();
   }
   return kSinRuntimeEntry;
 }
 
 #undef __
 
 }  // namespace dart