verilator/test_regress/t/t_recursive_module_bug.v
2022-03-05 15:04:13 +00:00

47 lines
1.2 KiB
Systemverilog

// DESCRIPTION: Verilator: Verilog Test module
//
// Copyright 2022 by Geza Lore. 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-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