Subzero: Fix a couple of debugging tools.

src/IceOperand.h

 //===- subzero/src/IceOperand.h - High-level operands -----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 509 matching lines @@
     NumVars = 1;
   }
   /// Number is unique across all variables, and is used as a (bit)vector index
   /// for liveness analysis.
   const SizeT Number;
   Cfg::IdentifierIndexType NameIndex = Cfg::IdentifierIndexInvalid;
   bool IsArgument = false;
   bool IsImplicitArgument = false;
   /// IgnoreLiveness means that the variable should be ignored when constructing
   /// and validating live ranges. This is usually reserved for the stack
-  /// pointer.
+  /// pointer and other physical registers specifically referenced by name.
   bool IgnoreLiveness = false;
   /// StackOffset is the canonical location on stack (only if RegNum==NoRegister
   /// || IsArgument).
   int32_t StackOffset = 0;
   /// RegNum is the allocated register, or NoRegister if it isn't
   /// register-allocated.
   int32_t RegNum = NoRegister;
   /// RegNumTmp is the tentative assignment during register allocation.
   int32_t RegNumTmp = NoRegister;
   RegRequirement RegRequirement = RR_MayHaveRegister;
@@ skipping 111 matching lines @@
 private:
   const Cfg *Func;
   MetadataKind Kind;
   CfgVector<VariableTracking> Metadata;
   const static InstDefList NoDefinitions;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEOPERAND_H