A load static of an initialized static final field can be converted to its value, as long as it is …

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 4426 matching lines @@
   }
   return changed;
 }
 
 
 ConstantPropagator::ConstantPropagator(
     FlowGraph* graph,
     const GrowableArray<BlockEntryInstr*>& ignored)
     : FlowGraphVisitor(ignored),
       graph_(graph),
-      unknown_(Object::transition_sentinel()),
-      non_constant_(Object::sentinel()),
+      unknown_(Object::unknown_constant()),
+      non_constant_(Object::non_constant()),
       reachable_(new BitVector(graph->preorder().length())),
       definition_marks_(new BitVector(graph->max_virtual_register_number())),
       block_worklist_(),
       definition_worklist_() {}
 
 
 void ConstantPropagator::Optimize(FlowGraph* graph) {
   GrowableArray<BlockEntryInstr*> ignored;
   ConstantPropagator cp(graph, ignored);
   cp.Analyze();
@@ skipping 416 matching lines @@
 }
 
 
 void ConstantPropagator::VisitStoreInstanceField(
     StoreInstanceFieldInstr* instr) {
   SetValue(instr, instr->value()->definition()->constant_value());
 }
 
 
 void ConstantPropagator::VisitLoadStaticField(LoadStaticFieldInstr* instr) {
+  const Field& field = instr->field();
+  ASSERT(field.is_static());
+  if (field.is_final()) {
+    Instance& obj = Instance::Handle(field.value());
+    if (obj.IsSmi() || obj.IsOld()) {
+      SetValue(instr, obj);
+      return;
+    }
+  }
   SetValue(instr, non_constant_);
 }
 
 
 void ConstantPropagator::VisitStoreStaticField(StoreStaticFieldInstr* instr) {
   SetValue(instr, instr->value()->definition()->constant_value());
 }
 
 
 void ConstantPropagator::VisitBooleanNegate(BooleanNegateInstr* instr) {
@@ skipping 1250 matching lines @@
 
   // Insert materializations at environment uses.
   const Class& cls = Class::Handle(alloc->constructor().Owner());
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, cls, *fields);
   }
 }
 
 
 }  // namespace dart