Implement a variation of scalar replacement for non-escaping allocations.

runtime/vm/flow_graph_optimizer.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_OPTIMIZER_H_
 #define VM_FLOW_GRAPH_OPTIMIZER_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 26 matching lines @@
 
   // Returns true if any instructions were canonicalized away.
   bool Canonicalize();
 
   void EliminateDeadPhis();
 
   void SelectRepresentations();
 
   void InferSmiRanges();
 
+  // Remove environments from the instructions which do not deoptimize.
+  void EliminateEnvironments();
+
   virtual void VisitStaticCall(StaticCallInstr* instr);
   virtual void VisitInstanceCall(InstanceCallInstr* instr);
   virtual void VisitRelationalOp(RelationalOpInstr* instr);
   virtual void VisitEqualityCompare(EqualityCompareInstr* instr);
   virtual void VisitBranch(BranchInstr* instr);
   virtual void VisitStrictCompare(StrictCompareInstr* instr);
 
   void InsertBefore(Instruction* next,
                     Instruction* instr,
                     Environment* env,
@@ skipping 254 matching lines @@
 
 // Rewrite diamond control flow patterns that materialize values to use more
 // efficient branchless code patterns if such are supported on the current
 // platform.
 class IfConverter : public AllStatic {
  public:
   static void Simplify(FlowGraph* flow_graph);
 };
 
 
+class AllocationSinking : public ZoneAllocated {
+ public:
+  explicit AllocationSinking(FlowGraph* flow_graph)
+      : flow_graph_(flow_graph),
+        materializations_(5) { }
+
+  void Optimize();
+
+  void DetachMaterializations();
+
+ private:
+  void InsertMaterializations(AllocateObjectInstr* alloc);
+
+  void CreateMaterializationAt(
+      Instruction* exit,
+      AllocateObjectInstr* alloc,
+      const Class& cls,
+      const ZoneGrowableArray<const Field*>& fields);
+
+  FlowGraph* flow_graph_;
+
+  GrowableArray<MaterializeObjectInstr*> materializations_;
+};
+
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_