Use type propagation to eliminate store barriers.

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 274 matching lines @@
   // However, the 'more specific than' relation is transitive and is used
   // here. In other words, if the compile type of the value is more specific
   // than the destination type, the run time type of the value, which is
   // guaranteed to be a subtype of the compile type, is also guaranteed to be
   // a subtype of the destination type and the type check can therefore be
   // eliminated.
   return compile_type.IsMoreSpecificThan(dst_type, NULL);
 }
 
 
+bool Value::NeedsStoreBuffer() const {
+  const intptr_t cid = ResultCid();
+  if ((cid == kSmiCid) || (cid == kBoolCid) || (cid == kNullCid)) {
+    return false;
+  }
+  if (BindsToConstant()) return false;

[Ivan Posva, 2012/08/25 00:20:51]

return !BindsToConstant();

[srdjan, 2012/08/25 00:25:52]

Done.

+  return true;
+}
+
+

[Ivan Posva, 2012/08/25 00:20:51]

Extra line.

[srdjan, 2012/08/25 00:25:52]

Done.

+
 RawAbstractType* PhiInstr::CompileType() const {
   ASSERT(!HasPropagatedType());
   // Since type propagation has not yet occured, we are reaching this phi via a
   // back edge phi input. Return null as compile type so that this input is
   // ignored in the first iteration of type propagation.
   return AbstractType::null();
 }
 
 
 RawAbstractType* PhiInstr::LeastSpecificInputType() const {
@@ skipping 1220 matching lines @@
                      ? UseDefinition(values()[i]->AsUse()->definition())
                      : val);
   }
   return copy;
 }
 
 
 #undef __
 
 }  // namespace dart