Revert "Fix scheduler to correctly schedule nested diamonds."

src/compiler/scheduler.cc

Index: src/compiler/scheduler.cc
diff --git a/src/compiler/scheduler.cc b/src/compiler/scheduler.cc
index cccd7fefe3ded0a55954f1fdf857a8364abf4c59..6a84591fc1b548ae865bbe58ea176854df315724 100644
--- a/src/compiler/scheduler.cc
+++ b/src/compiler/scheduler.cc
@@ -34,7 +34,7 @@ Scheduler::Scheduler(Zone* zone, Graph* graph, Schedule* schedule)
       schedule_(schedule),
       scheduled_nodes_(zone),
       schedule_root_nodes_(zone),
-      node_data_(graph_->NodeCount(), DefaultSchedulerData(zone), zone),
+      node_data_(graph_->NodeCount(), DefaultSchedulerData(), zone),
       has_floating_control_(false) {}
 
 
@@ -62,8 +62,8 @@ Schedule* Scheduler::ComputeSchedule(Graph* graph) {
 }
 
 
-Scheduler::SchedulerData Scheduler::DefaultSchedulerData(Zone* zone) {
-  SchedulerData def = {0, -1, false, false, kUnknown, NodeVector(zone)};
+Scheduler::SchedulerData Scheduler::DefaultSchedulerData() {
+  SchedulerData def = {0, -1, false, false, kUnknown};
   return def;
 }
 
@@ -182,7 +182,6 @@ class CFGBuilder {
     }
   }
 
-
   void BuildBlocks(Node* node) {
     switch (node->opcode()) {
       case IrOpcode::kLoop:
@@ -396,26 +395,6 @@ class PrepareUsesVisitor : public NullNodeVisitor {
       Trace("  Use count of #%d:%s (used by #%d:%s)++ = %d\n", to->id(),
             to->op()->mnemonic(), from->id(), from->op()->mnemonic(),
             scheduler_->GetData(to)->unscheduled_count_);
-      if (OperatorProperties::IsBasicBlockBegin(to->op()) &&
-          (from->opcode() == IrOpcode::kEffectPhi ||
-           from->opcode() == IrOpcode::kPhi) &&
-          scheduler_->GetData(to)->is_floating_control_ &&
-          !scheduler_->GetData(to)->is_connected_control_) {
-        for (InputIter i = from->inputs().begin(); i != from->inputs().end();
-             ++i) {
-          if (!NodeProperties::IsControlEdge(i.edge())) {
-            Scheduler::SchedulerData* data = scheduler_->GetData(to);
-            data->additional_dependencies.push_back(*i);
-            ++(scheduler_->GetData(*i)->unscheduled_count_);
-            Trace(
-                "  Use count of #%d:%s (additional dependency of #%d:%s)++ = "
-                "%d\n",
-                (*i)->id(), (*i)->op()->mnemonic(), to->id(),
-                to->op()->mnemonic(),
-                scheduler_->GetData(*i)->unscheduled_count_);
-          }
-        }
-      }
     }
   }
 
@@ -530,7 +509,6 @@ class ScheduleLateNodeVisitor : public NullNodeVisitor {
     if (schedule_->IsScheduled(node)) {
       return GenericGraphVisit::CONTINUE;
     }
-
     Scheduler::SchedulerData* data = scheduler_->GetData(node);
     DCHECK_EQ(Scheduler::kSchedulable, data->placement_);
 
@@ -633,24 +611,6 @@ class ScheduleLateNodeVisitor : public NullNodeVisitor {
         }
       }
     }
-
-    Scheduler::SchedulerData* data = scheduler_->GetData(node);
-    for (NodeVectorIter i = data->additional_dependencies.begin();
-         i != data->additional_dependencies.end(); ++i) {
-      Scheduler::SchedulerData* data = scheduler_->GetData(*i);
-      DCHECK(data->unscheduled_count_ > 0);
-      --data->unscheduled_count_;
-      if (FLAG_trace_turbo_scheduler) {
-        Trace(
-            "  Use count for #%d:%s (additional dependency of #%d:%s)-- = %d\n",
-            (*i)->id(), (*i)->op()->mnemonic(), node->id(),
-            node->op()->mnemonic(), data->unscheduled_count_);
-        if (data->unscheduled_count_ == 0) {
-          Trace("  newly eligible #%d:%s\n", (*i)->id(),
-                (*i)->op()->mnemonic());
-        }
-      }
-    }
   }
 
   Scheduler* scheduler_;
@@ -709,14 +669,16 @@ bool Scheduler::ConnectFloatingControl() {
     // TODO(titzer): we place at most one floating control structure per
     // basic block because scheduling currently can interleave phis from
     // one subgraph with the merges from another subgraph.
+    bool one_placed = false;
     for (size_t j = 0; j < block->NodeCount(); j++) {
       Node* node = block->NodeAt(block->NodeCount() - 1 - j);
       SchedulerData* data = GetData(node);
-      if (data->is_floating_control_ && !data->is_connected_control_) {
+      if (data->is_floating_control_ && !data->is_connected_control_ &&
+          !one_placed) {
         Trace("  Floating control #%d:%s was scheduled in B%d\n", node->id(),
               node->op()->mnemonic(), block->id().ToInt());
         ConnectFloatingControlSubgraph(block, node);
-        return true;
+        one_placed = true;
       }
     }
   }