Fix bug in aliasing computation for constant index.

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/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 5092 matching lines @@
       }
     }
   }
 
   void EnsureAliasingForIndexes() {
     BitVector* indexes = Get(Alias::Indexes());
     if (indexes == NULL) {
       return;
     }
 
-    // Constant indexes alias all non-constant indexes and non-constant
-    // indexes alias all constant indexes. Ids start at 1.
+    // Constant indexes alias all non-constant indexes.
+    // Non-constant indexes alias all constant indexes.
+    // First update alias set for const-indices, then
+    // update set for all indices. Ids start at 1.
     for (intptr_t id = 1; id <= max_index_id_; id++) {
       BitVector* const_indexes = Get(Alias::ConstantIndex(id));
       if (const_indexes != NULL) {
         const_indexes->AddAll(indexes);
+      }
+    }
+
+    for (intptr_t id = 1; id <= max_index_id_; id++) {
+      BitVector* const_indexes = Get(Alias::ConstantIndex(id));
+      if (const_indexes != NULL) {
         indexes->AddAll(const_indexes);
       }
     }
   }
 
   void AddIdForAlias(const Alias alias, intptr_t place_id) {
     const intptr_t idx = alias.ToIndex();
     while (sets_.length() <= idx) {
       sets_.Add(NULL);
     }
@@ skipping 3306 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart