diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc index 5c10278a9..f63b69acd 100644 --- a/passes/techmap/abc9.cc +++ b/passes/techmap/abc9.cc @@ -579,11 +579,46 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri module->connect(conn); continue; } - if (c->type == "\\NOT") { - RTLIL::Cell *cell = module->addCell(remap_name(c->name), "$_NOT_"); + if (c->type == "$_NOT_") { + RTLIL::Cell *cell; + RTLIL::SigBit a_bit = c->getPort("\\A").as_bit(); + RTLIL::SigBit y_bit = c->getPort("\\Y").as_bit(); + if (!lut_costs.empty()) { + // ABC can return NOT gates that drive POs + if (a_bit.wire->port_input) { + // If it's a NOT gate that comes from a primary input directly + // then implement it using a LUT + cell = module->addLut(remap_name(stringf("%s_lut", c->name.c_str())), + RTLIL::SigBit(module->wires_[remap_name(a_bit.wire->name)], a_bit.offset), + RTLIL::SigBit(module->wires_[remap_name(y_bit.wire->name)], y_bit.offset), + 1); + } + else { + // Otherwise, clone the driving LUT to guarantee that we + // won't increase the max logic depth + // (TODO: Optimise by not cloning unless will increase depth) + RTLIL::Cell* driver = mapped_mod->cell(stringf("%s_lut", a_bit.wire->name.c_str())); + log_assert(driver); + auto driver_a = driver->getPort("\\A").chunks(); + for (auto &chunk : driver_a) + chunk.wire = module->wires_[remap_name(chunk.wire->name)]; + RTLIL::Const driver_lut = driver->getParam("\\LUT"); + for (auto &b : driver_lut.bits) { + if (b == RTLIL::State::S0) b = RTLIL::State::S1; + else if (b == RTLIL::State::S1) b = RTLIL::State::S0; + } + cell = module->addLut(remap_name(stringf("%s_lut", c->name.c_str())), + driver_a, + RTLIL::SigBit(module->wires_[remap_name(y_bit.wire->name)], y_bit.offset), + driver_lut); + } + } + else { + cell = module->addCell(remap_name(c->name), "$_NOT_"); + cell->setPort("\\A", RTLIL::SigBit(module->wires_[remap_name(a_bit.wire->name)], a_bit.offset)); + cell->setPort("\\Y", RTLIL::SigBit(module->wires_[remap_name(y_bit.wire->name)], y_bit.offset)); + } if (markgroups) cell->attributes["\\abcgroup"] = map_autoidx; - cell->setPort("\\A", RTLIL::SigSpec(module->wires_[remap_name(c->getPort("\\A").as_wire()->name)])); - cell->setPort("\\Y", RTLIL::SigSpec(module->wires_[remap_name(c->getPort("\\Y").as_wire()->name)])); design->select(module, cell); continue; }