yosys/docs/source/code_examples/selections/foobaraddsub.v

module foobaraddsub(a, b, c, d, fa, fs, ba, bs);
  input [7:0] a, b, c, d;
  output [7:0] fa, fs, ba, bs;
  assign fa = a + (* foo *) b;
  assign fs = a - (* foo *) b;
  assign ba = c + (* bar *) d;
  assign bs = c - (* bar *) d;
endmodule