improve const correctness.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45646 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index b0eada8..bd8d210 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -827,7 +827,7 @@
       const CodeGenTarget &CGT = CGP.getTargetInfo();
       CodeGenInstruction &II = CGT.getInstruction(Op->getName());
       const DAGInstruction &Inst = CGP.getInstruction(Op);
-      TreePattern *InstPat = Inst.getPattern();
+      const TreePattern *InstPat = Inst.getPattern();
       // FIXME: Assume actual pattern comes before "implicit".
       TreePatternNode *InstPatNode =
         isRoot ? (InstPat ? InstPat->getTree(0) : Pattern)