Make the CFG depth-first traversal do more work for us.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
diff --git a/runtime/vm/flow_graph_builder.cc b/runtime/vm/flow_graph_builder.cc
index 7ec9f564b52161c948b68d46dc909485f626a107..d7b5139987dd4c3296d4e369950cf8128a708585 100644
--- a/runtime/vm/flow_graph_builder.cc
+++ b/runtime/vm/flow_graph_builder.cc
@@ -1671,8 +1671,11 @@ void FlowGraphBuilder::BuildGraph() {
   if (for_effect.entry() != NULL) {
     // Perform a depth-first traversal of the graph to build preorder and
     // postorder block orders.
-    for_effect.entry()->DepthFirstSearch(&preorder_block_entries_,
-                                         &postorder_block_entries_);
+    GrowableArray<BlockEntryInstr*> parent;

[Kevin Millikin (Google), 2012/03/19 18:05:12]

parent is currently ignored.

+    for_effect.entry()->DiscoverBlocks(NULL,  // Entry block predecessor.
+                                       &preorder_block_entries_,
+                                       &postorder_block_entries_,
+                                       &parent);
   }
   if (FLAG_print_flow_graph) {
     intptr_t length = postorder_block_entries_.length();