yosys/tests/opt/opt_share_cat_multiuser.v

module opt_share_test(
	input [15:0] 			a,
	input [15:0] 			b,
	input [15:0] 			c,
	input [15:0] 			d,
	input 						sel,
	output reg [47:0] res,
	);

	wire [15:0] 			add_res = a+b;
	wire [15:0] 			sub_res = a-b;
	wire [31: 0] 			cat1 = {add_res, c+d};
	wire [31: 0] 			cat2 = {sub_res, c-d};

	always @* begin
		case(sel)
			0: res = {cat1, add_res};
			1: res = {cat2, add_res};
		endcase
	end

endmodule