[turbofan] Propagate "deferredness" to dominated basic blocks.

src/compiler/scheduler.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <deque>
 #include <queue>
 
 #include "src/compiler/scheduler.h"
 
 #include "src/bit-vector.h"
@@ skipping 397 matching lines @@
     buffer[0] = schedule_->block(successors[0]);
     buffer[1] = schedule_->block(successors[1]);
   }
 
   void ConnectBranch(Node* branch) {
     BasicBlock* successor_blocks[2];
     CollectSuccessorBlocks(branch, successor_blocks, IrOpcode::kIfTrue,
                            IrOpcode::kIfFalse);
 
     // Consider branch hints.
-    // TODO(turbofan): Propagate the deferred flag to all blocks dominated by
-    // this IfTrue/IfFalse later.
     switch (BranchHintOf(branch->op())) {
       case BranchHint::kNone:
         break;
       case BranchHint::kTrue:
         successor_blocks[1]->set_deferred(true);
         break;
       case BranchHint::kFalse:
         successor_blocks[0]->set_deferred(true);
         break;
     }
@@ skipping 624 matching lines @@
     // For multiple predecessors, walk up the dominator tree until a common
     // dominator is found. Visitation order guarantees that all predecessors
     // except for backwards edges have been visited.
     for (++pred; pred != end; ++pred) {
       // Don't examine backwards edges.
       if ((*pred)->dominator_depth() < 0) continue;
       dominator = GetCommonDominator(dominator, *pred);
     }
     current->set_dominator(dominator);
     current->set_dominator_depth(dominator->dominator_depth() + 1);
+    // Propagate "deferredness" of the dominator.
+    if (dominator->deferred()) current->set_deferred(true);
     Trace("Block B%d's idom is B%d, depth = %d\n", current->id().ToInt(),
           dominator->id().ToInt(), current->dominator_depth());
   }
 }
 
 
 // -----------------------------------------------------------------------------
 // Phase 3: Prepare use counts for nodes.
 
 
@@ skipping 387 matching lines @@
   for (NodeVectorIter i = nodes->begin(); i != nodes->end(); ++i) {
     schedule_->SetBlockForNode(to, *i);
     scheduled_nodes_[to->id().ToSize()].push_back(*i);
   }
   nodes->clear();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8