Improve precision of range analysis by allowing it to track ranges across all int typed phis.

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/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 4844 matching lines @@
           BinarySmiOpInstr* smi_op = defn->AsBinarySmiOp();
           BinaryInt32OpInstr* int32_op = new(I) BinaryInt32OpInstr(
             smi_op->op_kind(),
             smi_op->left()->CopyWithType(),
             smi_op->right()->CopyWithType(),
             smi_op->DeoptimizationTarget());
 
           smi_op->ReplaceWith(int32_op, NULL);
         } else if (defn->IsPhi()) {
           defn->AsPhi()->set_representation(kUnboxedInt32);
+          ASSERT(defn->Type()->IsInt());
         }
       }
     }
   }
 }
 #else
 void FlowGraphOptimizer::WidenSmiToInt32() {
   // TODO(vegorov) ideally on 64-bit platforms we would like to narrow smi
   // operations to 32-bit where it saves tagging and untagging and allows
   // to use shorted (and faster) instructions. But we currently don't
@@ skipping 5052 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, alloc->cls(), *slots);
   }
 }
 
 
 }  // namespace dart