/* * yosys -- Yosys Open SYnthesis Suite * * Copyright (C) 2012 Clifford Wolf * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * */ #include "kernel/register.h" #include "kernel/bitpattern.h" #include "kernel/log.h" #include #include #include #include #include static void proc_rmdead(RTLIL::SwitchRule *sw, int &counter) { BitPatternPool pool(sw->signal); for (size_t i = 0; i < sw->cases.size(); i++) { bool is_default = sw->cases[i]->compare.size() == 0 && !pool.empty(); for (size_t j = 0; j < sw->cases[i]->compare.size(); j++) { RTLIL::SigSpec sig = sw->cases[i]->compare[j]; if (!sig.is_fully_const()) continue; if (!pool.take(sig)) sw->cases[i]->compare.erase(sw->cases[i]->compare.begin() + (j--)); } if (!is_default) { if (sw->cases[i]->compare.size() == 0) { delete sw->cases[i]; sw->cases.erase(sw->cases.begin() + (i--)); counter++; continue; } if (pool.empty()) sw->cases[i]->compare.clear(); } for (auto switch_it : sw->cases[i]->switches) proc_rmdead(switch_it, counter); if (is_default) pool.take_all(); } } struct ProcRmdeadPass : public Pass { ProcRmdeadPass() : Pass("proc_rmdead") { } virtual void execute(std::vector args, RTLIL::Design *design) { log_header("Executing PROC_RMDEAD pass (remove dead branches from decision trees).\n"); extra_args(args, 1, design); int total_counter = 0; for (auto &mod_it : design->modules) for (auto &proc_it : mod_it.second->processes) { int counter = 0; for (auto switch_it : proc_it.second->root_case.switches) proc_rmdead(switch_it, counter); if (counter > 0) log("Removed %d dead cases from process %s in module %s.\n", counter, proc_it.first.c_str(), mod_it.first.c_str()); total_counter += counter; } log("Removed a total of %d dead cases.\n", total_counter); } } ProcRmdeadPass;