Make unfold-batch-matmul into a command line option for the tfl-prepare-tf pass

PiperOrigin-RevId: 328319683
Change-Id: I674a6c0d789058737df9adaadebed5a56dfc21c1

tensorflow/compiler/mlir/lite/transforms/prepare_tf.cc

@@ -80,9 +80,11 @@ namespace {
 // Prepare TF operations in functions for subsequent legalization.
 class PrepareTFPass : public PassWrapper<PrepareTFPass, FunctionPass> {
  public:
-  explicit PrepareTFPass() : unfold_batch_matmul_(true) {}
-  explicit PrepareTFPass(bool unfold_batch_matmul)
-      : unfold_batch_matmul_(unfold_batch_matmul) {}
+  PrepareTFPass() = default;
+  PrepareTFPass(const PrepareTFPass &) {}
+  explicit PrepareTFPass(bool unfold_batch_matmul) {
+    unfold_batch_matmul_ = unfold_batch_matmul;
+  }
   void runOnFunction() override;
 
   void getDependentDialects(DialectRegistry &registry) const override {
@@ -91,7 +93,10 @@ class PrepareTFPass : public PassWrapper<PrepareTFPass, FunctionPass> {
   }
 
  private:
-  bool unfold_batch_matmul_;
+  Option<bool> unfold_batch_matmul_{
+      *this, "tfl-unfold-batch-matmul",
+      llvm::cl::desc("Unfold BatchMatMul into individual MatMul ops."),
+      llvm::cl::init(true)};
 };
 
 template <class TFFakeQuantOp>