verilator/test_regress/t/t_lint_latch_bad_3.v

76 lines
1.4 KiB
Systemverilog

// DESCRIPTION: Verilator: Verilog Test module for Issue#1609
//
// This file ONLY is placed into the Public Domain, for any use,
// without warranty, 2020 by Julien Margetts.
// SPDX-License-Identifier: Unlicense
module t (/*AUTOARG*/ reset, a, b, c, en, o1, o2, o3, o4, o5);
input reset;
input a;
input b;
input c;
input en;
output reg o1; // Always assigned
output reg o2; // "
output reg o3; // "
output reg o4; // "
output reg o5; // Latch
always_comb
if (reset)
begin
o1 = 1'b0;
o2 = 1'b0;
o3 = 1'b0;
o4 = 1'b0;
o5 = 1'b0;
end
else
begin
o1 = 1'b1;
if (en)
begin
o2 = 1'b0;
if (a)
begin
o3 = a;
o5 = 1'b1;
end
else
begin
o3 = ~a;
o5 = a;
end
// o3 is not assigned in either path of this if/else
// but no latch because always assigned above
if (c)
begin
o2 = a ^ b;
o4 = 1'b1;
end
else
o4 = ~a ^ b;
o2 = 1'b1;
end
else
begin
o2 = 1'b1;
if (b)
begin
o3 = ~a | b;
o5 = ~b;
end
else
begin
o3 = a & ~b;
// No assignment to o5, expect Warning-LATCH
end
o4 = 1'b0;
end
end
endmodule