Fold BIT_NOT and NEGATE during constant propagation.

runtime/vm/constant_propagator.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_CONSTANT_PROPAGATOR_H_
 #define VM_CONSTANT_PROPAGATOR_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 42 matching lines @@
     return value.raw() == unknown_.raw();
   }
   bool IsNonConstant(const Object& value) {
     return value.raw() == non_constant_.raw();
   }
   bool IsConstant(const Object& value) {
     return !IsNonConstant(value) && !IsUnknown(value);
   }
 
   void VisitBinaryIntegerOp(BinaryIntegerOpInstr* binary_op);
+  void VisitUnaryIntegerOp(UnaryIntegerOpInstr* unary_op);
 
   virtual void VisitBlocks() { UNREACHABLE(); }
 
 #define DECLARE_VISIT(type) virtual void Visit##type(type##Instr* instr);
   FOR_EACH_INSTRUCTION(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   Isolate* isolate() const { return graph_->isolate(); }
 
   FlowGraph* graph_;
@@ skipping 10 matching lines @@
 
   // Worklists of blocks and definitions.
   GrowableArray<BlockEntryInstr*> block_worklist_;
   DefinitionWorklist definition_worklist_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_CONSTANT_PROPAGATOR_H_