Subzero: Recognize single-block loops during loop depth analysis.

src/IceLoopAnalyzer.h

 //===- subzero/src/IceLoopAnalyzer.h - Loop Analysis ------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 60 matching lines @@
     }
     IndexT getLowLink() const { return LowLink; }
 
     void setOnStack(bool NewValue = true) { OnStack = NewValue; }
     bool isOnStack() const { return OnStack; }
 
     void setDeleted() { Deleted = true; }
     bool isDeleted() const { return Deleted; }
 
     void incrementLoopNestDepth();
+    bool hasSelfEdge() const;
 
   private:
     CfgNode *BB;
     NodeList::const_iterator Succ;
     IndexT Index;
     IndexT LowLink;
     bool OnStack;
     bool Deleted = false;
   };
 
@@ skipping 16 matching lines @@
   /// The index to assign to the next visited node.
   IndexT NextIndex = FirstDefinedIndex;
   /// The number of nodes which have been marked deleted. This is used to track
   /// when the iteration should end.
   LoopNodePtrList::size_type NumDeletedNodes = 0;
 };
 
 } // end of namespace Ice
 
 #endif //  SUBZERO_SRC_ICELOOPANALYZER_H