Set previous instruction pointers when building the graph.

runtime/vm/flow_graph_allocator.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_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph.h"
@@ skipping 1041 matching lines @@
 }
 
 
 static ParallelMoveInstr* CreateParallelMoveBefore(Instruction* instr,
                                                    intptr_t pos) {
   ASSERT(pos > 0);
   Instruction* prev = instr->previous();
   ParallelMoveInstr* move = prev->AsParallelMove();
   if ((move == NULL) || (move->lifetime_position() != pos)) {
     move = new ParallelMoveInstr();
-    move->set_next(prev->next());
-    prev->set_next(move);
-    move->next()->set_previous(move);
-    move->set_previous(prev);
+    prev->LinkTo(move);
+    move->LinkTo(instr);
     move->set_lifetime_position(pos);
   }
   return move;
 }
 
 
 static ParallelMoveInstr* CreateParallelMoveAfter(Instruction* instr,
                                                   intptr_t pos) {
   Instruction* next = instr->next();
   if (next->IsParallelMove() && (next->lifetime_position() == pos)) {
@@ skipping 1162 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart