Fix bugs in load elimination and type propagation.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
===================================================================
--- runtime/vm/flow_graph_type_propagator.cc	(revision 28924)
+++ runtime/vm/flow_graph_type_propagator.cc	(working copy)
@@ -18,6 +18,13 @@
 DECLARE_FLAG(bool, use_cha);
 
 
+void FlowGraphTypePropagator::Propagate(FlowGraph* flow_graph) {
+  FlowGraphTypePropagator propagator(flow_graph);
+  propagator.Propagate();
+  DEBUG_ASSERT(flow_graph->VerifyUseLists());

[Kevin Millikin (Google), 2013/10/21 13:05:23]

Except for a couple instances during inlining, all other calls to VerifyUseLists
are in compiler.cc.  We did that by design so it would be easy to see which
passes preserved use lists (though most of them do).

I sort of like to keep it that way, also because it flags places where the graph
can change and makes it easy to see that we have verification code everywhere.

[Florian Schneider, 2013/10/21 13:30:04]

Done.

+}
+
+
 FlowGraphTypePropagator::FlowGraphTypePropagator(FlowGraph* flow_graph)
     : FlowGraphVisitor(flow_graph->reverse_postorder()),
       flow_graph_(flow_graph),