Subzero: Prune unreachable nodes after constructing the Cfg.

src/IceCfgNode.h

 //===- subzero/src/IceCfgNode.h - Control flow graph node -------*- 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 CfgNode class, which represents a single
@@ skipping 15 matching lines @@
   CfgNode(const CfgNode &) = delete;
   CfgNode &operator=(const CfgNode &) = delete;
 
 public:
   static CfgNode *create(Cfg *Func, SizeT LabelIndex) {
     return new (Func->allocate<CfgNode>()) CfgNode(Func, LabelIndex);
   }
 
   // Access the label number and name for this node.
   SizeT getIndex() const { return Number; }
+  void resetIndex(SizeT NewNumber) { Number = NewNumber; }
   IceString getName() const;
   void setName(const IceString &NewName) {
     // Make sure that the name can only be set once.
     assert(NameIndex == Cfg::IdentifierIndexInvalid);
     if (!NewName.empty())
       NameIndex = Func->addIdentifierName(NewName);
   }
   IceString getAsmName() const {
     return ".L" + Func->getFunctionName() + "$" + getName();
   }
@@ skipping 17 matching lines @@
   void renumberInstructions();
   // Rough and generally conservative estimate of the number of
   // instructions in the block.  It is updated when an instruction is
   // added, but not when deleted.  It is recomputed during
   // renumberInstructions().
   InstNumberT getInstCountEstimate() const { return InstCountEstimate; }
 
   // Add a predecessor edge to the InEdges list for each of this
   // node's successors.
   void computePredecessors();
+  void computeSuccessors();
   CfgNode *splitIncomingEdge(CfgNode *Pred, SizeT InEdgeIndex);
 
   void placePhiLoads();
   void placePhiStores();
   void deletePhis();
   void advancedPhiLowering();
   void doAddressOpt();
   void doNopInsertion();
   void genCode();
   void livenessLightweight();
   bool liveness(Liveness *Liveness);
   void livenessAddIntervals(Liveness *Liveness, InstNumberT FirstInstNum,
                             InstNumberT LastInstNum);
   void contractIfEmpty();
   void doBranchOpt(const CfgNode *NextNode);
   void emit(Cfg *Func) const;
   void emitIAS(Cfg *Func) const;
   void dump(Cfg *Func) const;
 
 private:
   CfgNode(Cfg *Func, SizeT LabelIndex);
   Cfg *const Func;
-  const SizeT Number;                 // label index
+  SizeT Number;                       // label index
   Cfg::IdentifierIndexType NameIndex; // index into Cfg::NodeNames table
   bool HasReturn;                     // does this block need an epilog?
   bool NeedsPlacement;
   InstNumberT InstCountEstimate; // rough instruction count estimate
   NodeList InEdges;              // in no particular order
   NodeList OutEdges;             // in no particular order
   PhiList Phis;                  // unordered set of phi instructions
   InstList Insts;                // ordered list of non-phi instructions
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICECFGNODE_H