yosys/tests/various/wreduce.ys

read_verilog <<EOT
module wreduce_sub_test(input [3:0] i, input [7:0] j, output [8:0] o);
    assign o = (j >> 4) - i;
endmodule
EOT

hierarchy -auto-top
proc
design -save gold

opt_expr
wreduce

select -assert-count 1 t:$sub r:A_WIDTH=4 r:B_WIDTH=4 r:Y_WIDTH=5 %i %i %i

design -stash gate

design -import gold -as gold
design -import gate -as gate

miter -equiv -flatten -make_assert -make_outputs gold gate miter
sat -verify -prove-asserts -show-ports miter