Disable using CompileType for class check elimination.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 1024 matching lines @@
 }
 
 
 void StoreContextComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   // Nothing to do.  Context register were loaded by register allocator.
   ASSERT(locs()->in(0).reg() == CTX);
 }
 
 
 Definition* StrictCompareComp::TryReplace(BindInstr* instr) {
+  // TODO(srdjan): Do not use CompileType, as it is not correct.

[regis, 2012/08/15 00:11:46]

CompileType is not wrong. As I explained, it just cannot guarantee that an
instance is not null. For that, we would need value propagation. Or you may need
to emit null checks. Let's discuss.

[srdjan, 2012/08/15 00:16:46]

Oops. I realized that and changed the text to:

  // TODO(srdjan): Do not use CompileType for class check elimination.

   return NULL;
   UseVal* left_use = left()->AsUse();
   UseVal* right_use = right()->AsUse();
   if ((right_use == NULL) || (left_use == NULL)) return NULL;
   Definition* left = left_use->definition();
   BindInstr* right = right_use->definition()->AsBind();
   if (right == NULL) return NULL;
   ConstantVal* right_constant = right->computation()->AsConstant();
   if (right_constant == NULL) return NULL;
   // TODO(fschneider): Handle other cases: e === false and e !== true/false.
   // Handles e === true.
-  // const AbstractType& left_type = AbstractType::Handle(left->CompileType());
   if ((kind() == Token::kEQ_STRICT) &&
       (right_constant->value().raw() == Bool::True()) &&
       left_use->CompileTypeIsMoreSpecificThan(
           Type::Handle(Type::BoolInterface()))) {
     // Remove the constant from the graph.
     right->RemoveFromGraph();
     // Return left subexpression as the replacement for this instruction.
     return left;
   }
   return NULL;
@@ skipping 242 matching lines @@
   if (compiler->is_ssa()) {
     ASSERT(locs()->in(0).IsRegister());
     __ PushRegister(locs()->in(0).reg());
   }
 }
 
 
 #undef __
 
 }  // namespace dart