Subzero: Clean up live range construction.

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.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the Inst class and its target-independent
@@ skipping 51 matching lines @@
     FakeDef,  // not part of LLVM/PNaCl bitcode
     FakeUse,  // not part of LLVM/PNaCl bitcode
     FakeKill, // not part of LLVM/PNaCl bitcode
     Target    // target-specific low-level ICE
               // Anything >= Target is an InstTarget subclass.
   };
   InstKind getKind() const { return Kind; }
 
   InstNumberT getNumber() const { return Number; }
   void renumber(Cfg *Func);
-  enum { NumberDeleted = -1, NumberSentinel = 0 };
+  enum {
+    NumberDeleted = -1,
+    NumberSentinel = 0,
+    NumberInitial = 2,
+    NumberExtended = NumberInitial - 1
+  };
 
   bool isDeleted() const { return Deleted; }
   void setDeleted() { Deleted = true; }
   void deleteIfDead();
 
   bool hasSideEffects() const { return HasSideEffects; }
 
   bool isDestNonKillable() const { return IsDestNonKillable; }
   void setDestNonKillable() { IsDestNonKillable = true; }
 
@@ skipping 776 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