Fix instruction removal for 'as' test; the bug caused us to stop optimizing after an 'as' test.

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/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 3406 matching lines @@
     if (as_bool.raw() == Bool::True().raw()) {
       AddReceiverCheck(call);
       // Remove the original push arguments.
       for (intptr_t i = 0; i < call->ArgumentCount(); ++i) {
         PushArgumentInstr* push = call->PushArgumentAt(i);
         push->ReplaceUsesWith(push->value()->definition());
         push->RemoveFromGraph();
       }
       // Remove call, replace it with 'left'.
       call->ReplaceUsesWith(left);
-      call->RemoveFromGraph();
+      current_iterator()->RemoveCurrentFromGraph();

[zra, 2013/12/27 21:10:06]

Many other uses of RemoveCurrentFromGraph() are preceded by an ASSERT checking
that the correct node will be removed from the graph. Would it make sense to do
something like that here, too? Would it make sense to ASSERT before
RemoveFromGraph(), as well, since removing the wrong node caused the problem
here?

[srdjan, 2013/12/27 21:35:01]

Good point, added the assert.

       return;
     }
   }
   const String& dst_name = String::ZoneHandle(
       Symbols::New(Exceptions::kCastErrorDstName));
   AssertAssignableInstr* assert_as =
       new AssertAssignableInstr(call->token_pos(),
                                 new Value(left),
                                 new Value(instantiator),
                                 new Value(type_args),
@@ skipping 4845 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart