VM: Support phis with pair representations.

runtime/vm/flow_graph.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/flow_graph.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/il_printer.h"
 #include "vm/intermediate_language.h"
@@ skipping 903 matching lines @@
                                 GrowableArray<PhiInstr*>* live_phis,
                                 VariableLivenessAnalysis* variable_liveness) {
   // 1. Process phis first.
   if (block_entry->IsJoinEntry()) {
     JoinEntryInstr* join = block_entry->AsJoinEntry();
     if (join->phis() != NULL) {
       for (intptr_t i = 0; i < join->phis()->length(); ++i) {
         PhiInstr* phi = (*join->phis())[i];
         if (phi != NULL) {
           (*env)[i] = phi;
-          phi->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
+          AllocateSSAIndexes(phi);  // New SSA temp.
           if (block_entry->InsideTryBlock() && !phi->is_alive()) {
             // This is a safe approximation.  Inside try{} all locals are
             // used at every call implicitly, so we mark all phis as live
             // from the start.
             // TODO(fschneider): Improve this approximation to eliminate
             // more redundant phis.
             phi->mark_alive();
             live_phis->Add(phi);
           }
         }
@@ skipping 455 matching lines @@
 }
 
 
 bool BlockEffects::IsSideEffectFreePath(BlockEntryInstr* from,
                                         BlockEntryInstr* to) const {
   return available_at_[to->postorder_number()]->Contains(
       from->postorder_number());
 }
 
 }  // namespace dart