Remove optimization in unoptimized code that leave the graph in bad state (type test).

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, 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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 1402 matching lines @@
   const AbstractType& type = node->right()->AsTypeNode()->type();
   ASSERT(type.IsFinalized() && !type.IsMalformedOrMalbounded());
   const bool negate_result = (node->kind() == Token::kISNOT);
   // All objects are instances of type T if Object type is a subtype of type T.
   const Type& object_type = Type::Handle(Type::ObjectType());
   if (type.IsInstantiated() && object_type.IsSubtypeOf(type, NULL)) {
     // Must evaluate left side.
     EffectGraphVisitor for_left_value(owner());
     node->left()->Visit(&for_left_value);
     Append(for_left_value);
     ReturnDefinition(new ConstantInstr(Bool::Get(!negate_result)));

[regis, 2014/05/06 23:36:57]

Will this other optimization cause the same issue?

[srdjan, 2014/05/06 23:51:56]

Do not think so as we are not adding a ConstantInstr that then gest unused.

     return;
   }
 
-  // Eliminate the test if it can be performed successfully at compile time.
-  if ((node->left() != NULL) &&
-      node->left()->IsLiteralNode() &&
-      type.IsInstantiated()) {
-    const Instance& literal_value = node->left()->AsLiteralNode()->literal();
-    ConstantInstr* result = NULL;
-
-    Error& malformed_error = Error::Handle();
-    if (literal_value.IsInstanceOf(type,
-                                   TypeArguments::Handle(),
-                                   &malformed_error)) {
-      result = new ConstantInstr(Bool::Get(!negate_result));
-    } else {
-      result = new ConstantInstr(Bool::Get(negate_result));
-    }
-    ASSERT(malformed_error.IsNull());
-
-    ReturnDefinition(result);
-    return;
-  }
-
   ValueGraphVisitor for_left_value(owner());
   node->left()->Visit(&for_left_value);
   Append(for_left_value);
   PushArgumentInstr* push_left = PushArgument(for_left_value.value());
   PushArgumentInstr* push_instantiator = NULL;
   PushArgumentInstr* push_type_args = NULL;
   if (type.IsInstantiated()) {
     push_instantiator = PushArgument(BuildNullValue());
     push_type_args = PushArgument(BuildNullValue());
   } else {
@@ skipping 2466 matching lines @@
                                   function.token_pos(),
                                   LanguageError::kError,
                                   Heap::kNew,
                                   "FlowGraphBuilder Bailout: %s %s",
                                   String::Handle(function.name()).ToCString(),
                                   reason));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 }  // namespace dart