Move DeadControl into the JSGraph so that it can be reused.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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 "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
@@ skipping 2952 matching lines @@
     if (has_control) ++input_count_with_deps;
     if (has_effect) ++input_count_with_deps;
     Node** buffer = EnsureInputBufferSize(input_count_with_deps);
     memcpy(buffer, value_inputs, kPointerSize * value_input_count);
     Node** current_input = buffer + value_input_count;
     if (has_context) {
       *current_input++ = current_context();
     }
     if (has_framestate) {
       // The frame state will be inserted later. Here we misuse
-      // the dead_control node as a sentinel to be later overwritten
+      // the {DeadControl} node as a sentinel to be later overwritten
       // with the real frame state.
-      *current_input++ = dead_control();
+      *current_input++ = jsgraph()->DeadControl();
     }
     if (has_effect) {
       *current_input++ = environment_->GetEffectDependency();
     }
     if (has_control) {
       *current_input++ = environment_->GetControlDependency();
     }
     result = graph()->NewNode(op, input_count_with_deps, buffer, incomplete);
     if (has_effect) {
       environment_->UpdateEffectDependency(result);
@@ skipping 164 matching lines @@
     value->set_op(common()->Phi(kMachAnyTagged, inputs));
     value->InsertInput(graph_zone(), inputs - 1, other);
   } else if (value != other) {
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
-
-Node* AstGraphBuilder::dead_control() {
-  if (!dead_control_.is_set()) {
-    Node* dead_node = graph()->NewNode(common()->Dead());
-    dead_control_.set(dead_node);
-    return dead_node;
-  }
-  return dead_control_.get();
-}
-
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8