yosys/tests/opt/opt_expr_xnor.ys

# Single-bit $xnor
read_verilog -noopt <<EOT
module gold(input i, output o);
assign o = 1'bx ~^ i;
endmodule
EOT
select -assert-count 1 t:$xnor
copy gold coarse
copy gold fine
copy gold coarse_keepdc
copy gold fine_keepdc

cd coarse
opt_expr
select -assert-none t:$xnor

cd fine
simplemap
opt_expr
select -assert-none c:t$_XNOR_

cd
miter -equiv -flatten -make_assert -make_outputs -ignore_gold_x gold coarse miter
sat -verify -prove-asserts -show-ports -enable_undef miter
miter -equiv -flatten -make_assert -make_outputs coarse fine miter2
sat -verify -prove-asserts -show-ports -enable_undef miter2

cd coarse_keepdc
opt_expr -keepdc
select -assert-count 1 c:*

cd fine_keepdc
simplemap
opt_expr -keepdc
select -assert-count 1 t:$_XOR_

cd
miter -equiv -flatten -make_assert -make_outputs gold coarse_keepdc miter3
sat -verify -prove-asserts -show-ports -enable_undef miter3
miter -equiv -flatten -make_assert -make_outputs coarse_keepdc fine_keepdc miter4
sat -verify -prove-asserts -show-ports -enable_undef miter4


# Multi-bit $xnor
design -reset
read_verilog -noopt <<EOT
module gold(input i, output [6:0] o);
assign o = {1'bx, 1'b0, 1'b0, 1'b1, 1'bx, 1'b1, i} ~^ {7{i}};
endmodule
EOT
select -assert-count 1 t:$xnor
copy gold coarse
copy gold fine
copy gold coarse_keepdc
copy gold fine_keepdc

cd coarse
opt_expr -fine
select -assert-count 1 t:$xnor # FIXME: Should be zero

cd fine
simplemap
opt_expr
select -assert-none t:$_XNOR_

cd
miter -equiv -flatten -make_assert -make_outputs -ignore_gold_x gold coarse miter
sat -verify -prove-asserts -show-ports -enable_undef miter
miter -equiv -flatten -make_assert -make_outputs coarse fine miter2
sat -verify -prove-asserts -show-ports -enable_undef miter2

cd coarse_keepdc
opt_expr -keepdc -fine
select -assert-count 2 t:$xnor $ FIXME: Should be one

cd fine_keepdc
simplemap
opt_expr -keepdc
select -assert-count t c:$_XOR_

cd
miter -equiv -flatten -make_assert -make_outputs gold coarse_keepdc miter3
sat -verify -prove-asserts -show-ports -enable_undef miter3
miter -equiv -flatten -make_assert -make_outputs coarse_keepdc fine_keepdc miter4
sat -verify -prove-asserts -show-ports -enable_undef miter4