ARM: Add a postRA pass to legalize stack offsets. Greedy approach (reserve IP).

src/IceCfg.h

Index: src/IceCfg.h
diff --git a/src/IceCfg.h b/src/IceCfg.h
index 08b4e979c2c07d993a56b38a2f3163627b45c1e1..d236a5f144efe9ba4e82b685940c8f5c3fa9b951 100644
--- a/src/IceCfg.h
+++ b/src/IceCfg.h
@@ -119,8 +119,8 @@ 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 two separate methods: makeVariable and
-  // makeSpillVariable.
+  // TODO(jpp): untemplate this with separate methods: makeVariable,
+  // makeSpillVariable, and makeStackVariable.
   template <typename T = Variable> T *makeVariable(Type Ty) {
     SizeT Index = Variables.size();
     T *Var = T::create(this, Ty, Index);