Compute the loop nest depth of each CfgNode and weight Variables by it.

src/IceInst.h

 //===- subzero/src/IceInst.h - High-level instructions ----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 675 matching lines @@
 
 public:
   static InstStore *create(Cfg *Func, Operand *Data, Operand *Addr,
                            uint32_t Align = 1) {
     // TODO(kschimpf) Stop ignoring alignment specification.
     (void)Align;
     return new (Func->allocate<InstStore>()) InstStore(Func, Data, Addr);
   }
   Operand *getAddr() const { return getSrc(1); }
   Operand *getData() const { return getSrc(0); }
-  Variable *getRmwBeacon() const { return llvm::dyn_cast<Variable>(getSrc(2)); }
+  Variable *getRmwBeacon() const;
   void setRmwBeacon(Variable *Beacon);
   void dump(const Cfg *Func) const override;
   static bool classof(const Inst *Inst) { return Inst->getKind() == Store; }
 
 private:
   InstStore(Cfg *Func, Operand *Data, Operand *Addr);
 };
 
 /// Switch instruction.  The single source operand is captured as
 /// getSrc(0).
@@ skipping 275 matching lines @@
   static void noteHead(Ice::Inst *, Ice::Inst *) {}
   void deleteNode(Ice::Inst *) {}
 
 private:
   mutable ilist_half_node<Ice::Inst> Sentinel;
 };
 
 } // end of namespace llvm
 
 #endif // SUBZERO_SRC_ICEINST_H