region_if.getPred());

  // Move all regions from the old `mhlo.if` op to its replacement.
  new_if.getTrueBranch().takeBody(region_if.getTrueBranch());
  new_if.getFalseBranch().takeBody(region_if.getFalseBranch());

  // Forward result from old `mhlo.if` with replacement.
  SmallVector<Value> old_if_results = region_if.getResults();

        op.getLoc(), op->getResultTypes(), op.getPred(),
        /*is_stateless=*/false, /*_then_func_name=*/nullptr,
        /*_else_func_name=*/nullptr);
    new_op.getThenBranch().takeBody(op.getTrueBranch());
    new_op.getElseBranch().takeBody(op.getFalseBranch());
    ReplaceReturnOp(new_op.getThenBranch(), rewriter);
    ReplaceReturnOp(new_op.getElseBranch(), rewriter);