Eliminate class UseVal.

runtime/vm/flow_graph_builder.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 90 matching lines @@
   Instruction* exit() const { return exit_; }
 
   bool is_empty() const { return entry_ == NULL; }
   bool is_open() const { return is_empty() || exit_ != NULL; }
 
   void Bailout(const char* reason);
 
   // Append a graph fragment to this graph.  Assumes this graph is open.
   void Append(const EffectGraphVisitor& other_fragment);
   // Append a computation with one use.  Assumes this graph is open.
-  UseVal* Bind(Computation* computation);
+  Value* Bind(Computation* computation);
   // Append a computation with no uses.  Assumes this graph is open.
   void Do(Computation* computation);
   // Append a single (non-Definition, non-Entry) instruction.  Assumes this
   // graph is open.
   void AddInstruction(Instruction* instruction);
   // Append a Goto (unconditional control flow) instruction and close
   // the graph fragment.  Assumes this graph fragment is open.
   void Goto(JoinEntryInstr* join);
 
   // Append a 'diamond' branch and join to this graph, depending on which
@@ skipping 151 matching lines @@
   virtual void VisitStaticSetterNode(StaticSetterNode* node);
 
   Value* value() const { return value_; }
 
  protected:
   // Output parameters.
   Value* value_;
 
  private:
   // Helper to set the output state to return a Value.
-  virtual void ReturnValue(Value* value) {
-    ASSERT(value->IsUse());
-    value_ = value;
-  }
+  virtual void ReturnValue(Value* value) { value_ = value; }
 
   // Specify a computation as the final result.  Adds a Bind instruction to
   // the graph and returns its temporary value (i.e., set the output
   // parameters).
   virtual void ReturnComputation(Computation* computation) {
     ReturnValue(Bind(computation));
   }
 
   virtual void BuildTypeTest(ComparisonNode* node);
   virtual void BuildTypeCast(ComparisonNode* node);
@@ skipping 53 matching lines @@
   // Output parameters.
   TargetEntryInstr** true_successor_address_;
   TargetEntryInstr** false_successor_address_;
 
   intptr_t condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_