Subzero: Merge SpillVariable functionality directly into Variable.

src/IceCfg.h

Index: src/IceCfg.h
diff --git a/src/IceCfg.h b/src/IceCfg.h
index 181585f72ef2a3025bfbfedbe4133087cf3695ba..42e6ef121c519417faf5393e42a74bf62728e4f5 100644
--- a/src/IceCfg.h
+++ b/src/IceCfg.h
@@ -111,8 +111,8 @@ public:
 
   /// Create a new Variable with a particular type and an optional name. The
   /// Node argument is the node where the variable is defined.
-  // TODO(jpp): untemplate this with separate methods: makeVariable,
-  // makeSpillVariable, and makeStackVariable.
+  // TODO(jpp): untemplate this with separate methods: makeVariable and
+  // makeStackVariable.
   template <typename T = Variable> T *makeVariable(Type Ty) {
     SizeT Index = Variables.size();
     auto *Var = T::create(this, Ty, Index);