Subzero: Allow delaying Phi lowering until after register allocation.

src/IceCfg.h

 //===- subzero/src/IceCfg.h - Control flow graph ----------------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the Cfg class, which represents the control flow
@@ skipping 93 matching lines @@
   // Passes over the CFG.
   void translate();
   // After the CFG is fully constructed, iterate over the nodes and
   // compute the predecessor edges, in the form of
   // CfgNode::InEdges[].
   void computePredecessors();
   void renumberInstructions();
   void placePhiLoads();
   void placePhiStores();
   void deletePhis();
+  void advancedPhiLowering();
+  void reorderNodes();
   void doAddressOpt();
   void doArgLowering();
   void doNopInsertion();
   void genCode();
   void genFrame();
   void livenessLightweight();
   void liveness(LivenessMode Mode);
   bool validateLiveness() const;
   void deleteRedundantAssignments();
+  void contractEmptyNodes();
   void doBranchOpt();
 
   // Manage the CurrentNode field, which is used for validating the
   // Variable::DefNode field during dumping/emitting.
   void setCurrentNode(const CfgNode *Node) { CurrentNode = Node; }
   void resetCurrentNode() { setCurrentNode(NULL); }
   const CfgNode *getCurrentNode() const { return CurrentNode; }
 
   void emit();
   void dump(const IceString &Message = "");
@@ skipping 54 matching lines @@
   // validating Variable::DefNode.  Normally, a traversal over
   // CfgNodes maintains this, but before global operations like
   // register allocation, resetCurrentNode() should be called to avoid
   // spurious validation failures.
   const CfgNode *CurrentNode;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICECFG_H