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yosys/passes/sat/freduce.cc

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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
*
* 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/celltypes.h"
#include "kernel/consteval.h"
#include "kernel/sigtools.h"
#include "kernel/log.h"
#include "kernel/satgen.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <algorithm>
namespace {
bool inv_mode;
int verbose_level, reduce_counter, reduce_stop_at;
typedef std::map<RTLIL::SigBit, std::pair<RTLIL::Cell*, std::set<RTLIL::SigBit>>> drivers_t;
std::string dump_prefix;
struct equiv_bit_t
{
int depth;
bool inverted;
RTLIL::Cell *drv;
RTLIL::SigBit bit;
bool operator<(const equiv_bit_t &other) const {
if (depth != other.depth)
return depth < other.depth;
if (inverted != other.inverted)
return inverted < other.inverted;
if (drv != other.drv)
return drv < other.drv;
return bit < other.bit;
}
};
struct CountBitUsage
{
SigMap &sigmap;
std::map<RTLIL::SigBit, int> &cache;
CountBitUsage(SigMap &sigmap, std::map<RTLIL::SigBit, int> &cache) : sigmap(sigmap), cache(cache) { }
void operator()(RTLIL::SigSpec &sig) {
std::vector<RTLIL::SigBit> vec = sigmap(sig).to_sigbit_vector();
for (auto &bit : vec)
cache[bit]++;
}
};
struct FindReducedInputs
{
SigMap &sigmap;
drivers_t &drivers;
ezDefaultSAT ez;
std::set<RTLIL::Cell*> ez_cells;
SatGen satgen;
std::map<RTLIL::SigBit, int> sat_pi;
std::vector<int> sat_pi_uniq_bitvec;
FindReducedInputs(SigMap &sigmap, drivers_t &drivers) :
sigmap(sigmap), drivers(drivers), satgen(&ez, &sigmap)
{
satgen.model_undef = true;
}
int get_bits(int val)
{
int bits = 0;
for (int i = 8*sizeof(int); val; i = i >> 1)
if (val >> (i-1)) {
bits += i;
val = val >> i;
}
return bits;
}
void register_pi_bit(RTLIL::SigBit bit)
{
if (sat_pi.count(bit) != 0)
return;
satgen.setContext(&sigmap, "A");
int sat_a = satgen.importSigSpec(bit).front();
ez.assume(ez.NOT(satgen.importUndefSigSpec(bit).front()));
satgen.setContext(&sigmap, "B");
int sat_b = satgen.importSigSpec(bit).front();
ez.assume(ez.NOT(satgen.importUndefSigSpec(bit).front()));
int idx = sat_pi.size();
size_t idx_bits = get_bits(idx);
if (sat_pi_uniq_bitvec.size() != idx_bits) {
sat_pi_uniq_bitvec.push_back(ez.frozen_literal(stringf("uniq_%d", int(idx_bits)-1)));
for (auto &it : sat_pi)
ez.assume(ez.OR(ez.NOT(it.second), ez.NOT(sat_pi_uniq_bitvec.back())));
}
log_assert(sat_pi_uniq_bitvec.size() == idx_bits);
sat_pi[bit] = ez.frozen_literal(stringf("p, falsei_%s", log_signal(bit)));
ez.assume(ez.IFF(ez.XOR(sat_a, sat_b), sat_pi[bit]));
for (size_t i = 0; i < idx_bits; i++)
if ((idx & (1 << i)) == 0)
ez.assume(ez.OR(ez.NOT(sat_pi[bit]), ez.NOT(sat_pi_uniq_bitvec[i])));
else
ez.assume(ez.OR(ez.NOT(sat_pi[bit]), sat_pi_uniq_bitvec[i]));
}
void register_cone_worker(std::set<RTLIL::SigBit> &pi, std::set<RTLIL::SigBit> &sigdone, RTLIL::SigBit out)
{
if (out.wire == NULL)
return;
if (sigdone.count(out) != 0)
return;
sigdone.insert(out);
if (drivers.count(out) != 0) {
std::pair<RTLIL::Cell*, std::set<RTLIL::SigBit>> &drv = drivers.at(out);
if (ez_cells.count(drv.first) == 0) {
satgen.setContext(&sigmap, "A");
if (!satgen.importCell(drv.first))
log_error("Can't create SAT model for cell %s (%s)!\n", RTLIL::id2cstr(drv.first->name), RTLIL::id2cstr(drv.first->type));
satgen.setContext(&sigmap, "B");
if (!satgen.importCell(drv.first))
log_abort();
ez_cells.insert(drv.first);
}
for (auto &bit : drv.second)
register_cone_worker(pi, sigdone, bit);
} else {
register_pi_bit(out);
pi.insert(out);
}
}
void register_cone(std::vector<RTLIL::SigBit> &pi, RTLIL::SigBit out)
{
std::set<RTLIL::SigBit> pi_set, sigdone;
register_cone_worker(pi_set, sigdone, out);
pi.clear();
pi.insert(pi.end(), pi_set.begin(), pi_set.end());
}
void analyze(std::vector<RTLIL::SigBit> &reduced_inputs, RTLIL::SigBit output, int prec)
{
if (verbose_level >= 1)
log("[%2d%%] Analyzing input cone for signal %s:\n", prec, log_signal(output));
std::vector<RTLIL::SigBit> pi;
register_cone(pi, output);
if (verbose_level >= 1)
log(" Found %d input signals and %d cells.\n", int(pi.size()), int(ez_cells.size()));
satgen.setContext(&sigmap, "A");
int output_a = satgen.importSigSpec(output).front();
int output_undef_a = satgen.importUndefSigSpec(output).front();
satgen.setContext(&sigmap, "B");
int output_b = satgen.importSigSpec(output).front();
int output_undef_b = satgen.importUndefSigSpec(output).front();
std::set<int> unused_pi_idx;
for (size_t i = 0; i < pi.size(); i++)
unused_pi_idx.insert(i);
while (1)
{
std::vector<int> model_pi_idx;
std::vector<int> model_expr;
std::vector<bool> model;
for (size_t i = 0; i < pi.size(); i++)
if (unused_pi_idx.count(i) != 0) {
model_pi_idx.push_back(i);
model_expr.push_back(sat_pi.at(pi[i]));
}
if (!ez.solve(model_expr, model, ez.expression(ezSAT::OpOr, model_expr), ez.XOR(output_a, output_b), ez.NOT(output_undef_a), ez.NOT(output_undef_b)))
break;
int found_count = 0;
for (size_t i = 0; i < model_pi_idx.size(); i++)
if (model[i]) {
if (verbose_level >= 2)
log(" Found relevant input: %s\n", log_signal(pi[model_pi_idx[i]]));
unused_pi_idx.erase(model_pi_idx[i]);
found_count++;
}
log_assert(found_count == 1);
}
for (size_t i = 0; i < pi.size(); i++)
if (unused_pi_idx.count(i) == 0)
reduced_inputs.push_back(pi[i]);
if (verbose_level >= 1)
log(" Reduced input cone contains %d inputs.\n", int(reduced_inputs.size()));
}
};
struct PerformReduction
{
SigMap &sigmap;
drivers_t &drivers;
std::set<std::pair<RTLIL::SigBit, RTLIL::SigBit>> &inv_pairs;
ezDefaultSAT ez;
SatGen satgen;
std::vector<int> sat_pi, sat_out, sat_def;
std::vector<RTLIL::SigBit> out_bits, pi_bits;
std::vector<bool> out_inverted;
std::vector<int> out_depth;
int cone_size;
int register_cone_worker(std::set<RTLIL::Cell*> &celldone, std::map<RTLIL::SigBit, int> &sigdepth, RTLIL::SigBit out)
{
if (out.wire == NULL)
return 0;
if (sigdepth.count(out) != 0)
return sigdepth.at(out);
if (drivers.count(out) != 0) {
std::pair<RTLIL::Cell*, std::set<RTLIL::SigBit>> &drv = drivers.at(out);
if (celldone.count(drv.first) == 0) {
if (!satgen.importCell(drv.first))
log_error("Can't create SAT model for cell %s (%s)!\n", RTLIL::id2cstr(drv.first->name), RTLIL::id2cstr(drv.first->type));
celldone.insert(drv.first);
}
int max_child_depth = 0;
for (auto &bit : drv.second)
max_child_depth = std::max(register_cone_worker(celldone, sigdepth, bit), max_child_depth);
sigdepth[out] = max_child_depth + 1;
} else {
pi_bits.push_back(out);
sat_pi.push_back(satgen.importSigSpec(out).front());
ez.assume(ez.NOT(satgen.importUndefSigSpec(out).front()));
sigdepth[out] = 0;
}
return sigdepth.at(out);
}
PerformReduction(SigMap &sigmap, drivers_t &drivers, std::set<std::pair<RTLIL::SigBit, RTLIL::SigBit>> &inv_pairs, std::vector<RTLIL::SigBit> &bits, int cone_size) :
sigmap(sigmap), drivers(drivers), inv_pairs(inv_pairs), satgen(&ez, &sigmap), out_bits(bits), cone_size(cone_size)
{
satgen.model_undef = true;
std::set<RTLIL::Cell*> celldone;
std::map<RTLIL::SigBit, int> sigdepth;
for (auto &bit : bits) {
out_depth.push_back(register_cone_worker(celldone, sigdepth, bit));
sat_out.push_back(satgen.importSigSpec(bit).front());
sat_def.push_back(ez.NOT(satgen.importUndefSigSpec(bit).front()));
}
if (inv_mode && cone_size > 0) {
if (!ez.solve(sat_out, out_inverted, ez.expression(ezSAT::OpAnd, sat_def)))
log_error("Solving for initial model failed!\n");
for (size_t i = 0; i < sat_out.size(); i++)
if (out_inverted.at(i))
sat_out[i] = ez.NOT(sat_out[i]);
} else
out_inverted = std::vector<bool>(sat_out.size(), false);
}
void analyze_const(std::vector<std::vector<equiv_bit_t>> &results, int idx)
{
if (verbose_level == 1)
log(" Finding const value for %s.\n", log_signal(out_bits[idx]));
bool can_be_set = ez.solve(ez.AND(sat_out[idx], sat_def[idx]));
bool can_be_clr = ez.solve(ez.AND(ez.NOT(sat_out[idx]), sat_def[idx]));
log_assert(!can_be_set || !can_be_clr);
RTLIL::SigBit value(RTLIL::State::Sx);
if (can_be_set)
value = RTLIL::State::S1;
if (can_be_clr)
value = RTLIL::State::S0;
if (verbose_level == 1)
log(" Constant value for this signal: %s\n", log_signal(value));
int result_idx = -1;
for (size_t i = 0; i < results.size(); i++) {
if (results[i].front().bit == value) {
result_idx = i;
break;
}
}
if (result_idx == -1) {
result_idx = results.size();
results.push_back(std::vector<equiv_bit_t>());
equiv_bit_t bit;
bit.depth = 0;
bit.inverted = false;
bit.drv = NULL;
bit.bit = value;
results.back().push_back(bit);
}
equiv_bit_t bit;
bit.depth = 1;
bit.inverted = false;
bit.drv = drivers.count(out_bits[idx]) ? drivers.at(out_bits[idx]).first : NULL;
bit.bit = out_bits[idx];
results[result_idx].push_back(bit);
}
void analyze(std::vector<std::set<int>> &results, std::map<int, int> &results_map, std::vector<int> &bucket, std::string indent1, std::string indent2)
{
std::string indent = indent1 + indent2;
const char *indt = indent.c_str();
if (bucket.size() <= 1)
return;
if (verbose_level == 1)
log("%s Trying to shatter bucket with %d signals.\n", indt, int(bucket.size()));
if (verbose_level > 1) {
std::vector<RTLIL::SigBit> bucket_sigbits;
for (int idx : bucket)
bucket_sigbits.push_back(out_bits[idx]);
log("%s Trying to shatter bucket with %d signals: %s\n", indt, int(bucket.size()), log_signal(bucket_sigbits));
}
std::vector<int> sat_set_list, sat_clr_list;
for (int idx : bucket) {
sat_set_list.push_back(ez.AND(sat_out[idx], sat_def[idx]));
sat_clr_list.push_back(ez.AND(ez.NOT(sat_out[idx]), sat_def[idx]));
}
std::vector<int> modelVars = sat_out;
std::vector<bool> model;
modelVars.insert(modelVars.end(), sat_def.begin(), sat_def.end());
if (verbose_level >= 2)
modelVars.insert(modelVars.end(), sat_pi.begin(), sat_pi.end());
if (ez.solve(modelVars, model, ez.expression(ezSAT::OpOr, sat_set_list), ez.expression(ezSAT::OpOr, sat_clr_list)))
{
int iter_count = 1;
while (1)
{
sat_set_list.clear();
sat_clr_list.clear();
std::vector<int> sat_def_list;
for (int idx : bucket)
if (!model[sat_out.size() + idx]) {
sat_set_list.push_back(ez.AND(sat_out[idx], sat_def[idx]));
sat_clr_list.push_back(ez.AND(ez.NOT(sat_out[idx]), sat_def[idx]));
} else {
sat_def_list.push_back(sat_def[idx]);
}
if (!ez.solve(modelVars, model, ez.expression(ezSAT::OpOr, sat_set_list), ez.expression(ezSAT::OpOr, sat_clr_list), ez.expression(ezSAT::OpAnd, sat_def_list)))
break;
iter_count++;
}
if (verbose_level >= 1) {
int count_set = 0, count_clr = 0, count_undef = 0;
for (int idx : bucket)
if (!model[sat_out.size() + idx])
count_undef++;
else if (model[idx])
count_set++;
else
count_clr++;
log("%s After %d iterations: %d set vs. %d clr vs %d undef\n", indt, iter_count, count_set, count_clr, count_undef);
}
if (verbose_level >= 2) {
for (size_t i = 0; i < pi_bits.size(); i++)
log("%s -> PI %c == %s\n", indt, model[2*sat_out.size() + i] ? '1' : '0', log_signal(pi_bits[i]));
for (int idx : bucket)
log("%s -> OUT %c == %s%s\n", indt, model[sat_out.size() + idx] ? model[idx] ? '1' : '0' : 'x',
out_inverted.at(idx) ? "~" : "", log_signal(out_bits[idx]));
}
std::vector<int> buckets_a;
std::vector<int> buckets_b;
for (int idx : bucket) {
if (!model[sat_out.size() + idx] || model[idx])
buckets_a.push_back(idx);
if (!model[sat_out.size() + idx] || !model[idx])
buckets_b.push_back(idx);
}
analyze(results, results_map, buckets_a, indent1 + ".", indent2 + " ");
analyze(results, results_map, buckets_b, indent1 + "x", indent2 + " ");
}
else
{
std::vector<int> undef_slaves;
for (int idx : bucket) {
std::vector<int> sat_def_list;
for (int idx2 : bucket)
if (idx != idx2)
sat_def_list.push_back(sat_def[idx2]);
if (ez.solve(ez.NOT(sat_def[idx]), ez.expression(ezSAT::OpOr, sat_def_list)))
undef_slaves.push_back(idx);
}
if (undef_slaves.size() == bucket.size()) {
if (verbose_level >= 1)
log("%s Complex undef overlap. None of the signals covers the others.\n", indt);
// FIXME: We could try to further shatter a group with complex undef overlaps
return;
}
for (int idx : undef_slaves)
out_depth[idx] = std::numeric_limits<int>::max();
if (verbose_level >= 1) {
log("%s Found %d equivialent signals:", indt, int(bucket.size()));
for (int idx : bucket)
log("%s%s%s", idx == bucket.front() ? " " : ", ", out_inverted[idx] ? "~" : "", log_signal(out_bits[idx]));
log("\n");
}
int result_idx = -1;
for (int idx : bucket) {
if (results_map.count(idx) == 0)
continue;
if (result_idx == -1) {
result_idx = results_map.at(idx);
continue;
}
int result_idx2 = results_map.at(idx);
results[result_idx].insert(results[result_idx2].begin(), results[result_idx2].end());
for (int idx2 : results[result_idx2])
results_map[idx2] = result_idx;
results[result_idx2].clear();
}
if (result_idx == -1) {
result_idx = results.size();
results.push_back(std::set<int>());
}
results[result_idx].insert(bucket.begin(), bucket.end());
}
}
void analyze(std::vector<std::vector<equiv_bit_t>> &results, int perc)
{
std::vector<int> bucket;
for (size_t i = 0; i < sat_out.size(); i++)
bucket.push_back(i);
std::vector<std::set<int>> results_buf;
std::map<int, int> results_map;
analyze(results_buf, results_map, bucket, stringf("[%2d%%] %d ", perc, cone_size), "");
for (auto &r : results_buf)
{
if (r.size() <= 1)
continue;
if (verbose_level >= 1) {
std::vector<RTLIL::SigBit> r_sigbits;
for (int idx : r)
r_sigbits.push_back(out_bits[idx]);
log(" Found group of %d equivialent signals: %s\n", int(r.size()), log_signal(r_sigbits));
}
std::vector<int> undef_slaves;
for (int idx : r) {
std::vector<int> sat_def_list;
for (int idx2 : r)
if (idx != idx2)
sat_def_list.push_back(sat_def[idx2]);
if (ez.solve(ez.NOT(sat_def[idx]), ez.expression(ezSAT::OpOr, sat_def_list)))
undef_slaves.push_back(idx);
}
if (undef_slaves.size() == bucket.size()) {
if (verbose_level >= 1)
log(" Complex undef overlap. None of the signals covers the others.\n");
// FIXME: We could try to further shatter a group with complex undef overlaps
return;
}
for (int idx : undef_slaves)
out_depth[idx] = std::numeric_limits<int>::max();
std::vector<equiv_bit_t> result;
for (int idx : r) {
equiv_bit_t bit;
bit.depth = out_depth[idx];
bit.inverted = out_inverted[idx];
bit.drv = drivers.count(out_bits[idx]) ? drivers.at(out_bits[idx]).first : NULL;
bit.bit = out_bits[idx];
result.push_back(bit);
}
std::sort(result.begin(), result.end());
if (result.front().inverted)
for (auto &bit : result)
bit.inverted = !bit.inverted;
for (size_t i = 1; i < result.size(); i++) {
std::pair<RTLIL::SigBit, RTLIL::SigBit> p(result[0].bit, result[i].bit);
if (inv_pairs.count(p) != 0)
result.erase(result.begin() + i);
}
if (result.size() > 1)
results.push_back(result);
}
}
};
struct FreduceWorker
{
RTLIL::Design *design;
RTLIL::Module *module;
SigMap sigmap;
drivers_t drivers;
std::set<std::pair<RTLIL::SigBit, RTLIL::SigBit>> inv_pairs;
FreduceWorker(RTLIL::Design *design, RTLIL::Module *module) : design(design), module(module), sigmap(module)
{
}
bool find_bit_in_cone(std::set<RTLIL::Cell*> &celldone, RTLIL::SigBit needle, RTLIL::SigBit haystack)
{
if (needle == haystack)
return true;
if (haystack.wire == NULL || needle.wire == NULL || drivers.count(haystack) == 0)
return false;
std::pair<RTLIL::Cell*, std::set<RTLIL::SigBit>> &drv = drivers.at(haystack);
if (celldone.count(drv.first))
return false;
celldone.insert(drv.first);
for (auto &bit : drv.second)
if (find_bit_in_cone(celldone, needle, bit))
return true;
return false;
}
bool find_bit_in_cone(RTLIL::SigBit needle, RTLIL::SigBit haystack)
{
std::set<RTLIL::Cell*> celldone;
return find_bit_in_cone(celldone, needle, haystack);
}
void dump()
{
std::string filename = stringf("%s_%s_%05d.il", dump_prefix.c_str(), RTLIL::id2cstr(module->name), reduce_counter);
log("%s Writing dump file `%s'.\n", reduce_counter ? " " : "", filename.c_str());
Pass::call(design, stringf("dump -outfile %s %s", filename.c_str(), design->selected_active_module.empty() ? module->name.c_str() : ""));
}
int run()
{
log("Running functional reduction on module %s:\n", RTLIL::id2cstr(module->name));
CellTypes ct;
ct.setup_internals();
ct.setup_stdcells();
int bits_full_total = 0;
std::vector<std::set<RTLIL::SigBit>> batches;
for (auto &it : module->wires_)
if (it.second->port_input) {
batches.push_back(sigmap(it.second).to_sigbit_set());
bits_full_total += it.second->width;
}
for (auto &it : module->cells_) {
if (ct.cell_known(it.second->type)) {
std::set<RTLIL::SigBit> inputs, outputs;
for (auto &port : it.second->connections()) {
std::vector<RTLIL::SigBit> bits = sigmap(port.second).to_sigbit_vector();
if (ct.cell_output(it.second->type, port.first))
outputs.insert(bits.begin(), bits.end());
else
inputs.insert(bits.begin(), bits.end());
}
std::pair<RTLIL::Cell*, std::set<RTLIL::SigBit>> drv(it.second, inputs);
for (auto &bit : outputs)
drivers[bit] = drv;
batches.push_back(outputs);
bits_full_total += outputs.size();
}
if (inv_mode && it.second->type == "$_INV_")
inv_pairs.insert(std::pair<RTLIL::SigBit, RTLIL::SigBit>(sigmap(it.second->getPort("\\A")), sigmap(it.second->getPort("\\Y"))));
}
int bits_count = 0;
int bits_full_count = 0;
std::map<std::vector<RTLIL::SigBit>, std::vector<RTLIL::SigBit>> buckets;
for (auto &batch : batches)
{
for (auto &bit : batch)
if (bit.wire != NULL && design->selected(module, bit.wire))
goto found_selected_wire;
bits_full_count += batch.size();
continue;
found_selected_wire:
log(" Finding reduced input cone for signal batch %s%c\n",
log_signal(batch), verbose_level ? ':' : '.');
FindReducedInputs infinder(sigmap, drivers);
for (auto &bit : batch) {
std::vector<RTLIL::SigBit> inputs;
infinder.analyze(inputs, bit, 100 * bits_full_count / bits_full_total);
buckets[inputs].push_back(bit);
bits_full_count++;
bits_count++;
}
}
log(" Sorted %d signal bits into %d buckets.\n", bits_count, int(buckets.size()));
int bucket_count = 0;
std::vector<std::vector<equiv_bit_t>> equiv;
for (auto &bucket : buckets)
{
bucket_count++;
if (bucket.second.size() == 1)
continue;
if (bucket.first.size() == 0) {
log(" Finding const values for bucket %s%c\n", log_signal(bucket.second), verbose_level ? ':' : '.');
PerformReduction worker(sigmap, drivers, inv_pairs, bucket.second, bucket.first.size());
for (size_t idx = 0; idx < bucket.second.size(); idx++)
worker.analyze_const(equiv, idx);
} else {
log(" Trying to shatter bucket %s%c\n", log_signal(bucket.second), verbose_level ? ':' : '.');
PerformReduction worker(sigmap, drivers, inv_pairs, bucket.second, bucket.first.size());
worker.analyze(equiv, 100 * bucket_count / (buckets.size() + 1));
}
}
std::map<RTLIL::SigBit, int> bitusage;
module->rewrite_sigspecs(CountBitUsage(sigmap, bitusage));
if (!dump_prefix.empty())
dump();
log(" Rewiring %d equivialent groups:\n", int(equiv.size()));
int rewired_sigbits = 0;
for (auto &grp : equiv)
{
log(" [%05d] Using as master for group: %s\n", ++reduce_counter, log_signal(grp.front().bit));
RTLIL::SigSpec inv_sig;
for (size_t i = 1; i < grp.size(); i++)
{
if (!design->selected(module, grp[i].bit.wire)) {
log(" Skipping not-selected slave: %s\n", log_signal(grp[i].bit));
continue;
}
if (grp[i].bit.wire->port_id == 0 && bitusage[grp[i].bit] <= 1) {
log(" Skipping unused slave: %s\n", log_signal(grp[i].bit));
continue;
}
if (find_bit_in_cone(grp[i].bit, grp.front().bit)) {
log(" Skipping dependency of master: %s\n", log_signal(grp[i].bit));
continue;
}
log(" Connect slave%s: %s\n", grp[i].inverted ? " using inverter" : "", log_signal(grp[i].bit));
RTLIL::Cell *drv = drivers.at(grp[i].bit).first;
RTLIL::Wire *dummy_wire = module->addWire(NEW_ID);
for (auto &port : drv->connections_)
if (ct.cell_output(drv->type, port.first))
sigmap(port.second).replace(grp[i].bit, dummy_wire, &port.second);
if (grp[i].inverted)
{
if (inv_sig.size() == 0)
{
inv_sig = module->addWire(NEW_ID);
RTLIL::Cell *inv_cell = module->addCell(NEW_ID, "$_INV_");
inv_cell->setPort("\\A", grp[0].bit);
inv_cell->setPort("\\Y", inv_sig);
}
module->connect(RTLIL::SigSig(grp[i].bit, inv_sig));
}
else
module->connect(RTLIL::SigSig(grp[i].bit, grp[0].bit));
rewired_sigbits++;
}
if (!dump_prefix.empty())
dump();
if (reduce_counter == reduce_stop_at) {
log(" Reached limit passed using -stop option. Skipping all further reductions.\n");
break;
}
}
log(" Rewired a total of %d signal bits in module %s.\n", rewired_sigbits, RTLIL::id2cstr(module->name));
return rewired_sigbits;
}
};
} /* namespace */
struct FreducePass : public Pass {
FreducePass() : Pass("freduce", "perform functional reduction") { }
virtual void help()
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" freduce [options] [selection]\n");
log("\n");
log("This pass performs functional reduction in the circuit. I.e. if two nodes are\n");
log("equivialent, they are merged to one node and one of the redundant drivers is\n");
log("disconnected. A subsequent call to 'clean' will remove the redundant drivers.\n");
log("\n");
log(" -v, -vv\n");
log(" enable verbose or very verbose output\n");
log("\n");
log(" -inv\n");
log(" enable explicit handling of inverted signals\n");
log("\n");
log(" -stop <n>\n");
log(" stop after <n> reduction operations. this is mostly used for\n");
log(" debugging the freduce command itself.\n");
log("\n");
log(" -dump <prefix>\n");
log(" dump the design to <prefix>_<module>_<num>.il after each reduction\n");
log(" operation. this is mostly used for debugging the freduce command.\n");
log("\n");
log("This pass is undef-aware, i.e. it considers don't-care values for detecting\n");
log("equivialent nodes.\n");
log("\n");
log("All selected wires are considered for rewiring. The selected cells cover the\n");
log("circuit that is analyzed.\n");
log("\n");
}
virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
{
reduce_counter = 0;
reduce_stop_at = 0;
verbose_level = 0;
inv_mode = false;
dump_prefix = std::string();
log_header("Executing FREDUCE pass (perform functional reduction).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-v") {
verbose_level = 1;
continue;
}
if (args[argidx] == "-vv") {
verbose_level = 2;
continue;
}
if (args[argidx] == "-inv") {
inv_mode = true;
continue;
}
if (args[argidx] == "-stop" && argidx+1 < args.size()) {
reduce_stop_at = atoi(args[++argidx].c_str());
continue;
}
if (args[argidx] == "-dump" && argidx+1 < args.size()) {
dump_prefix = args[++argidx];
continue;
}
break;
}
extra_args(args, argidx, design);
int bitcount = 0;
for (auto &mod_it : design->modules_) {
RTLIL::Module *module = mod_it.second;
if (design->selected(module))
bitcount += FreduceWorker(design, module).run();
}
log("Rewired a total of %d signal bits.\n", bitcount);
}
} FreducePass;
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