Add canonicalize optimization for branches.

runtime/vm/intermediate_language.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_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1017 matching lines @@
   virtual Definition* AsDefinition() { return this; }
 
   bool IsComparison() { return (AsComparison() != NULL); }
   virtual ComparisonInstr* AsComparison() { return NULL; }
 
   // Overridden by definitions that push arguments.
   virtual intptr_t ArgumentCount() const { return 0; }
 
   intptr_t temp_index() const { return temp_index_; }
   void set_temp_index(intptr_t index) { temp_index_ = index; }
+  void ClearTempIndex() { temp_index_ = -1; }
 
   intptr_t ssa_temp_index() const { return ssa_temp_index_; }
   void set_ssa_temp_index(intptr_t index) {
     ASSERT(index >= 0);
     ASSERT(is_used());
     ssa_temp_index_ = index;
   }
   bool HasSSATemp() const { return ssa_temp_index_ >= 0; }
+  void ClearSSATempIndex() { ssa_temp_index_ = -1; }
 
   bool is_used() const { return (use_kind_ != kEffect); }
   void set_use_kind(UseKind kind) { use_kind_ = kind; }
 
   // Compile time type of the definition, which may be requested before type
   // propagation during graph building.
   virtual RawAbstractType* CompileType() const = 0;
 
   virtual intptr_t ResultCid() const = 0;
 
@@ skipping 464 matching lines @@
   virtual LocationSummary* locs();
   virtual intptr_t DeoptimizationTarget() const;
   virtual Representation RequiredInputRepresentation(intptr_t i) const;
 
   // Replace the comparison with another, leaving the branch intact.
   void ReplaceWith(ComparisonInstr* other,
                    ForwardInstructionIterator* ignored) {
     comparison_ = other;
   }
 
+  virtual Instruction* Canonicalize(FlowGraphOptimizer* optimizer);
+
   virtual void PrintTo(BufferFormatter* f) const;
 
  private:
   ComparisonInstr* comparison_;
   const bool is_checked_;
 
   DISALLOW_COPY_AND_ASSIGN(BranchInstr);
 };
 
 
@@ skipping 2792 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_