Validate well-formedness of the use lists in debug mode.

runtime/vm/flow_graph_optimizer.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_optimizer.h"
 
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
@@ skipping 136 matching lines @@
 static bool HasOnlyTwoDouble(const ICData& ic_data) {
   return (ic_data.NumberOfChecks() == 1) &&
       ICDataHasReceiverArgumentClassIds(ic_data, kDoubleCid, kDoubleCid);
 }
 
 
 static void RemovePushArguments(InstanceCallComp* comp) {
   // Remove original push arguments.
   for (intptr_t i = 0; i < comp->ArgumentCount(); ++i) {
     PushArgumentInstr* push = comp->ArgumentAt(i);
+    push->ReplaceUsesWith(push->value());
     push->RemoveFromGraph();
   }
 }
 
 
 // Returns true if all targets are the same.
 // TODO(srdjan): if targets are native use their C_function to compare.
 static bool HasOneTarget(const ICData& ic_data) {
   ASSERT(ic_data.NumberOfChecks() > 0);
   const Function& first_target = Function::Handle(ic_data.GetTargetAt(0));
@@ skipping 881 matching lines @@
       DirectChainedHashMap<BindInstr*> child_map(*map);  // Copy map.
       OptimizeRecursive(child, &child_map);
     } else {
       OptimizeRecursive(child, map);  // Reuse map for the last child.
     }
   }
 }
 
 
 }  // namespace dart