// DESCRIPTION: Verilator: Verilog Test module
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of either the GNU Lesser General Public License Version 3
// or the Perl Artistic License Version 2.0.
// SPDX-FileCopyrightText: 2022 Geza Lore
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0

// This hits a case where parameter specialization of recursive modules
// used to yield a module list that was not topologically sorted, which
// then caused V3Inline to blow up as it assumes that.

module top #(
    parameter N = 8
) (
    input wire [N-1:0] i,
    output wire [N-1:0] o,
    output wire [N-1:0] a
);

  sub #(
      .N(N)
  ) inst (
      .i(i),
      .o(a)
  );

  generate
    if (N > 1) begin : recursive
      top #(
          .N(N / 2)
      ) hi (
          .i(i[N-1:N/2]),
          .o(o[N-1:N/2]),
          .a()
      );
      top #(
          .N(N / 2)
      ) lo (
          .i(i[N/2-1:0]),
          .o(o[N/2-1:0]),
          .a()
      );
    end
    else begin : base
      assign o = i;
    end
  endgenerate

endmodule

module sub #(
    parameter N = 8
) (
    input wire [N-1:0] i,
    output wire [N-1:0] o
);

  generate
    if (N > 1) begin : recursive
      sub #(
          .N(N / 2)
      ) hi (
          .i(i[N-1:N/2]),
          .o(o[N-1:N/2])
      );
      sub #(
          .N(N / 2)
      ) lo (
          .i(i[N/2-1:0]),
          .o(o[N/2-1:0])
      );
    end
    else begin : base
      assign o = i;
    end
  endgenerate

endmodule