[turbofan] Avoid creating singleton state-values for the accumulator.

src/compiler/js-graph.h

 // 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.
 
 #ifndef V8_COMPILER_JS_GRAPH_H_
 #define V8_COMPILER_JS_GRAPH_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/compiler/common-node-cache.h"
 #include "src/compiler/common-operator.h"
@@ skipping 124 matching lines @@
   }
 
   // Creates a dummy Constant node, used to satisfy calling conventions of
   // stubs and runtime functions that do not require a context.
   Node* NoContextConstant() { return ZeroConstant(); }
 
   // Creates an empty StateValues node, used when we don't have any concrete
   // values for a certain part of the frame state.
   Node* EmptyStateValues();
 
+  // Typed state values with a single dead input. This is useful to represent
+  // dead accumulator.
+  Node* SingleDeadTypedStateValues();
+
   // Create a control node that serves as dependency for dead nodes.
   Node* Dead();
 
   CommonOperatorBuilder* common() const { return common_; }
   JSOperatorBuilder* javascript() const { return javascript_; }
   SimplifiedOperatorBuilder* simplified() const { return simplified_; }
   MachineOperatorBuilder* machine() const { return machine_; }
   Graph* graph() const { return graph_; }
   Zone* zone() const { return graph()->zone(); }
   Isolate* isolate() const { return isolate_; }
@@ skipping 19 matching lines @@
     kStaleRegisterConstant,
     kUndefinedConstant,
     kTheHoleConstant,
     kTrueConstant,
     kFalseConstant,
     kNullConstant,
     kZeroConstant,
     kOneConstant,
     kNaNConstant,
     kEmptyStateValues,
+    kSingleDeadTypedStateValues,
     kDead,
     kNumCachedNodes  // Must remain last.
   };
 
   Isolate* isolate_;
   Graph* graph_;
   CommonOperatorBuilder* common_;
   JSOperatorBuilder* javascript_;
   SimplifiedOperatorBuilder* simplified_;
   MachineOperatorBuilder* machine_;
   CommonNodeCache cache_;
   Node* cached_nodes_[kNumCachedNodes];
 
   Node* NumberConstant(double value);
 
   DISALLOW_COPY_AND_ASSIGN(JSGraph);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif