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opt_expr: const_xnor replacement to pad Y with 1'b1

This commit is contained in:
Eddie Hung 2020-04-24 14:13:45 -07:00
parent ebd6fa945d
commit b5f38f8342
2 changed files with 48 additions and 1 deletions
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3
passes/opt/opt_expr.cc
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@ -575,7 +575,8 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
if (cell->type.in(ID($xnor), ID($_XNOR_))) { if (cell->type.in(ID($xnor), ID($_XNOR_))) {
cover("opt.opt_expr.const_xnor"); cover("opt.opt_expr.const_xnor");
// For consistency since simplemap does $xnor -> $_XOR_ + $_NOT_ // For consistency since simplemap does $xnor -> $_XOR_ + $_NOT_
replace_cell(assign_map, module, cell, "const_xnor", ID::Y, RTLIL::State::S1); int width = cell->getParam(ID::Y_WIDTH).as_int();
replace_cell(assign_map, module, cell, "const_xnor", ID::Y, SigSpec(RTLIL::State::S1, width));
goto next_cell; goto next_cell;
} }
log_abort(); log_abort();

46
tests/opt/opt_expr_xnor.ys
View File

@ -83,3 +83,49 @@ miter -equiv -flatten -make_assert -make_outputs gold coarse_keepdc miter3
sat -verify -prove-asserts -show-ports -enable_undef miter3 sat -verify -prove-asserts -show-ports -enable_undef miter3
miter -equiv -flatten -make_assert -make_outputs coarse_keepdc fine_keepdc miter4 miter -equiv -flatten -make_assert -make_outputs coarse_keepdc fine_keepdc miter4
sat -verify -prove-asserts -show-ports -enable_undef miter4 sat -verify -prove-asserts -show-ports -enable_undef miter4
# Single-bit $xnor extension
design -reset
read_verilog -noopt <<EOT
module gold(input i, output [1:0] o, p, q);
assign o = i ~^ i;
assign p = 1'b0 ~^ i;
assign q = 1'b1 ~^ i;
endmodule
EOT
select -assert-count 3 t:$xnor
copy gold coarse
copy gold fine
copy gold coarse_keepdc
copy gold fine_keepdc
cd coarse
opt_expr -fine
select -assert-none t:$xnor
cd fine
simplemap
opt_expr
select -assert-none t:$_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 1 t:$xnor
cd fine_keepdc
simplemap
opt_expr -keepdc
select -assert-count 0 c:$_XNOR_
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