[AVX] Constify Inits

Make references to Inits const everywhere.  This is the final step
before making them unique.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136485 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/SetTheory.h b/utils/TableGen/SetTheory.h
index 6e8313b..f6123c7 100644
--- a/utils/TableGen/SetTheory.h
+++ b/utils/TableGen/SetTheory.h
@@ -70,7 +70,7 @@
 
     /// apply - Apply this operator to Expr's arguments and insert the result
     /// in Elts.
-    virtual void apply(SetTheory&, DagInit *Expr, RecSet &Elts) =0;
+    virtual void apply(SetTheory&, const DagInit *Expr, RecSet &Elts) =0;
   };
 
   /// Expander - A callback function that can transform a Record representing a
@@ -115,7 +115,7 @@
   void addOperator(StringRef Name, Operator*);
 
   /// evaluate - Evaluate Expr and append the resulting set to Elts.
-  void evaluate(Init *Expr, RecSet &Elts);
+  void evaluate(const Init *Expr, RecSet &Elts);
 
   /// evaluate - Evaluate a sequence of Inits and append to Elts.
   template<typename Iter>