VM: Support phis with pair representations.

runtime/vm/flow_graph_builder.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_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 471 matching lines @@
     // The immediate dominator of the join is the last one in the ordered
     // intersection.
     join_dominators.Last()->AddDominatedBlock(join);
     *exit_block = join;
     *last_instruction = join;
 
     // If the call has uses, create a phi of the returns.
     if (call_->HasUses()) {
       // Add a phi of the return values.
       PhiInstr* phi = new(Z) PhiInstr(join, num_exits);
-      phi->set_ssa_temp_index(caller_graph_->alloc_ssa_temp_index());
+      caller_graph_->AllocateSSAIndexes(phi);
       phi->mark_alive();
       for (intptr_t i = 0; i < num_exits; ++i) {
         ReturnAt(i)->RemoveEnvironment();
         phi->SetInputAt(i, ValueAt(i));
       }
       join->InsertPhi(phi);
       join->InheritDeoptTargetAfter(caller_graph_, call_, phi);
       return phi;
     } else {
       // In the case that the result is unused, remove the return value uses
@@ skipping 4191 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart