Subzero: Prototype to make use of RegNumT::No Register more concise

src/IceOperand.h

Index: src/IceOperand.h
diff --git a/src/IceOperand.h b/src/IceOperand.h
index a20308660ced41885cc20c2d8cdf756a5ee4ffe3..bb390f95fe3f36bd22134a9ff51dc9636e2ddc7c 100644
--- a/src/IceOperand.h
+++ b/src/IceOperand.h
@@ -441,7 +441,9 @@ public:
   // Define NoRegisterValue as an enum value so that it can be used as an
   // argument for the public ctor if desired.
   enum { NoRegisterValue = std::numeric_limits<BaseType>::max() };
-  const static RegNumT NoRegister /* = NoRegisterValue */;
+
+  bool hasValue() const { return Value != NoRegisterValue; }
+  bool hasNoValue() const { return !hasValue(); }
 
 private:
   BaseType Value = NoRegisterValue;
@@ -646,14 +648,14 @@ public:
     return "lv$" + getName(Func);
   }
 
-  bool hasReg() const { return getRegNum() != RegNumT::NoRegister; }
+  bool hasReg() const { return getRegNum().hasValue(); }
   RegNumT getRegNum() const { return RegNum; }
   void setRegNum(RegNumT NewRegNum) {
     // Regnum shouldn't be set more than once.
     assert(!hasReg() || RegNum == NewRegNum);
     RegNum = NewRegNum;
   }
-  bool hasRegTmp() const { return getRegNumTmp() != RegNumT::NoRegister; }
+  bool hasRegTmp() const { return getRegNumTmp().hasValue(); }
   RegNumT getRegNumTmp() const { return RegNumTmp; }
   void setRegNumTmp(RegNumT NewRegNum) { RegNumTmp = NewRegNum; }
 
@@ -711,7 +713,7 @@ public:
   void dump(const Cfg *Func, Ostream &Str) const override;
 
   /// Return reg num of base register, if different from stack/frame register.
-  virtual RegNumT getBaseRegNum() const { return RegNumT::NoRegister; }
+  virtual RegNumT getBaseRegNum() const { return RegNumT(); }
 
   static bool classof(const Operand *Operand) {
     OperandKind Kind = Operand->getKind();
@@ -743,9 +745,9 @@ protected:
   RegClass RegisterClass;
   /// RegNum is the allocated register, or NoRegister if it isn't

[Jim Stichnoth, 2016/02/13 18:58:10]

/// RegNum is the allocated register (as long as RegNum.hasValue() is true).

[rkotlerimgtec, 2016/02/14 00:04:05]

Done.

   /// register-allocated.
-  RegNumT RegNum = RegNumT::NoRegister;
+  RegNumT RegNum;
   /// RegNumTmp is the tentative assignment during register allocation.
-  RegNumT RegNumTmp = RegNumT::NoRegister;
+  RegNumT RegNumTmp;
   /// StackOffset is the canonical location on stack (only if
   /// RegNum==NoRegister || IsArgument).

[Jim Stichnoth, 2016/02/13 18:58:10]

RegNum.hasNoValue()

[rkotlerimgtec, 2016/02/14 00:04:05]

Done.

   int32_t StackOffset = 0;