Apply clang-tidy fixes for performance-for-range-copy in rank_specialization.cc (NFC)

PiperOrigin-RevId: 418728399
Change-Id: I5c32d13934161c4e9af44bac47cfc182b7e4c44d
diff --git a/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/transforms/rank_specialization.cc b/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/transforms/rank_specialization.cc
index b52c436..c61a446 100644
--- a/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/transforms/rank_specialization.cc
+++ b/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/transforms/rank_specialization.cc
@@ -221,7 +221,7 @@
     // Map operands and copy operations of the preceding cluster into the new
     // body.
     BlockAndValueMapping bvm;
-    for (auto it : llvm::enumerate(preceding_body->getArguments()))
+    for (const auto &it : llvm::enumerate(preceding_body->getArguments()))
       bvm.map(it.value(), new_body->getArgument(it.index()));
     for (Operation &nested_op : preceding_body->without_terminator())
       rewriter.clone(nested_op, bvm);