Fix scheduler to correctly schedule nested diamonds.

src/compiler/scheduler.h

Index: src/compiler/scheduler.h
diff --git a/src/compiler/scheduler.h b/src/compiler/scheduler.h
index 9e806814dec2aa7188a7118ccaf303648b50b1ae..2cef2270f09f82803a85ed62cc396d56708a32ec 100644
--- a/src/compiler/scheduler.h
+++ b/src/compiler/scheduler.h
@@ -36,8 +36,9 @@ class Scheduler {
     bool is_connected_control_;  // {true} if control-connected to the end node.
     bool is_floating_control_;   // {true} if control, but not control-connected
                                  // to the end node.
-    Placement placement_ : 3;    // Whether the node is fixed, schedulable,
+    Placement placement_;        // Whether the node is fixed, schedulable,
                                  // or not yet known.
+    NodeVector additional_dependencies;
   };
 
   Zone* zone_;
@@ -50,7 +51,7 @@ class Scheduler {
 
   Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
 
-  SchedulerData DefaultSchedulerData();
+  SchedulerData DefaultSchedulerData(Zone* zone);
 
   SchedulerData* GetData(Node* node) {
     DCHECK(node->id() < static_cast<int>(node_data_.size()));