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Refactor "opt_rmdff -sat" 

Signed-off-by: Clifford Wolf <clifford@clifford.at>
This commit is contained in:
Clifford Wolf 2019-06-20 13:44:21 +02:00
parent 73bd1d59a7
commit 2454ad99bf
4 changed files with 57 additions and 372 deletions
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317
passes/opt/netlist.h
View File

@ -1,317 +0,0 @@
/* -*- c++ -*-
* 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.
*
*/
#ifndef SATGEN_ALGO_H
#define SATGEN_ALGO_H
#include "kernel/celltypes.h"
#include "kernel/rtlil.h"
#include "kernel/sigtools.h"
#include <stack>
YOSYS_NAMESPACE_BEGIN
CellTypes comb_cells_filt()
{
CellTypes ct;
ct.setup_internals();
ct.setup_stdcells();
return ct;
}
struct Netlist {
RTLIL::Module *module;
SigMap sigmap;
CellTypes ct;
dict<RTLIL::SigBit, Cell *> sigbit_driver_map;
dict<RTLIL::Cell *, std::set<RTLIL::SigBit>> cell_inputs_map;
Netlist(RTLIL::Module *module) : module(module), sigmap(module), ct(module->design) { setup_netlist(module, ct); }
Netlist(RTLIL::Module *module, const CellTypes &ct) : module(module), sigmap(module), ct(ct) { setup_netlist(module, ct); }
RTLIL::Cell *driver_cell(RTLIL::SigBit sig) const
{
sig = sigmap(sig);
if (!sigbit_driver_map.count(sig)) {
return NULL;
}
return sigbit_driver_map.at(sig);
}
RTLIL::SigSpec driver_port(RTLIL::SigBit sig)
{
RTLIL::Cell *cell = driver_cell(sig);
if (!cell) {
return RTLIL::SigSpec();
}
for (auto &port : cell->connections_) {
if (ct.cell_output(cell->type, port.first)) {
RTLIL::SigSpec port_sig = sigmap(port.second);
for (int i = 0; i < GetSize(port_sig); i++) {
if (port_sig[i] == sig) {
return port.second[i];
}
}
}
}
return RTLIL::SigSpec();
}
void setup_netlist(RTLIL::Module *module, const CellTypes &ct)
{
for (auto cell : module->cells()) {
if (ct.cell_known(cell->type)) {
std::set<RTLIL::SigBit> inputs, outputs;
for (auto &port : cell->connections()) {
std::vector<RTLIL::SigBit> bits = sigmap(port.second).to_sigbit_vector();
if (ct.cell_output(cell->type, port.first))
outputs.insert(bits.begin(), bits.end());
else
inputs.insert(bits.begin(), bits.end());
}
cell_inputs_map[cell] = inputs;
for (auto &bit : outputs) {
sigbit_driver_map[bit] = cell;
};
}
}
}
};
namespace detail
{
struct NetlistConeWireIter : public std::iterator<std::input_iterator_tag, RTLIL::SigBit> {
using set_iter_t = std::set<RTLIL::SigBit>::iterator;
const Netlist &net;
RTLIL::SigBit sig;
bool sentinel;
CellTypes *cell_filter;
std::stack<std::pair<set_iter_t, set_iter_t>> dfs_path_stack;
std::set<RTLIL::Cell *> cells_visited;
NetlistConeWireIter(const Netlist &net) : net(net), sentinel(true), cell_filter(NULL) {}
NetlistConeWireIter(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL)
: net(net), sig(sig), sentinel(false), cell_filter(cell_filter)
{
}
const RTLIL::SigBit &operator*() const { return sig; };
bool operator!=(const NetlistConeWireIter &other) const
{
if (sentinel || other.sentinel) {
return sentinel != other.sentinel;
} else {
return sig != other.sig;
}
}
bool operator==(const NetlistConeWireIter &other) const
{
if (sentinel || other.sentinel) {
return sentinel == other.sentinel;
} else {
return sig == other.sig;
}
}
void next_sig_in_dag()
{
while (1) {
if (dfs_path_stack.empty()) {
sentinel = true;
return;
}
auto &cell_inputs_iter = dfs_path_stack.top().first;
auto &cell_inputs_iter_guard = dfs_path_stack.top().second;
cell_inputs_iter++;
if (cell_inputs_iter != cell_inputs_iter_guard) {
sig = *cell_inputs_iter;
return;
} else {
dfs_path_stack.pop();
}
}
}
NetlistConeWireIter &operator++()
{
RTLIL::Cell *cell = net.driver_cell(sig);
if (!cell) {
next_sig_in_dag();
return *this;
}
if (cells_visited.count(cell)) {
next_sig_in_dag();
return *this;
}
if ((cell_filter) && (!cell_filter->cell_known(cell->type))) {
next_sig_in_dag();
return *this;
}
auto &inputs = net.cell_inputs_map.at(cell);
dfs_path_stack.push(std::make_pair(inputs.begin(), inputs.end()));
cells_visited.insert(cell);
sig = (*dfs_path_stack.top().first);
return *this;
}
};
struct NetlistConeWireIterable {
const Netlist &net;
RTLIL::SigBit sig;
CellTypes *cell_filter;
NetlistConeWireIterable(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL) : net(net), sig(sig), cell_filter(cell_filter)
{
}
NetlistConeWireIter begin() { return NetlistConeWireIter(net, sig, cell_filter); }
NetlistConeWireIter end() { return NetlistConeWireIter(net); }
};
struct NetlistConeCellIter : public std::iterator<std::input_iterator_tag, RTLIL::Cell *> {
const Netlist &net;
NetlistConeWireIter sig_iter;
NetlistConeCellIter(const Netlist &net) : net(net), sig_iter(net) {}
NetlistConeCellIter(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL) : net(net), sig_iter(net, sig, cell_filter)
{
if ((!sig_iter.sentinel) && (!has_driver_cell(*sig_iter))) {
++(*this);
}
}
bool has_driver_cell(const RTLIL::SigBit &s) { return net.sigbit_driver_map.count(s); }
RTLIL::Cell *operator*() const { return net.sigbit_driver_map.at(*sig_iter); };
bool operator!=(const NetlistConeCellIter &other) const { return sig_iter != other.sig_iter; }
bool operator==(const NetlistConeCellIter &other) const { return sig_iter == other.sig_iter; }
NetlistConeCellIter &operator++()
{
while (true) {
++sig_iter;
if (sig_iter.sentinel) {
return *this;
}
RTLIL::Cell* cell = net.driver_cell(*sig_iter);
if (!cell) {
continue;
}
if ((sig_iter.cell_filter) && (!sig_iter.cell_filter->cell_known(cell->type))) {
continue;
}
if (!sig_iter.cells_visited.count(cell)) {
return *this;
}
}
}
};
struct NetlistConeCellIterable {
const Netlist &net;
RTLIL::SigBit sig;
CellTypes *cell_filter;
NetlistConeCellIterable(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL) : net(net), sig(sig), cell_filter(cell_filter)
{
}
NetlistConeCellIter begin() { return NetlistConeCellIter(net, sig, cell_filter); }
NetlistConeCellIter end() { return NetlistConeCellIter(net); }
};
// struct NetlistConeInputsIter : public std::iterator<std::input_iterator_tag, const RTLIL::Cell *> {
// const Netlist &net;
// RTLIL::SigBit sig;
// NetlistConeWireIter sig_iter;
// bool has_driver_cell(const RTLIL::SigBit &s) { return net.sigbit_driver_map.count(s); }
// NetlistConeInputsIter(const Netlist &net, RTLIL::SigBit sig = NULL) : net(net), sig(sig), sig_iter(net, sig)
// {
// if ((sig != NULL) && (has_driver_cell(sig_iter))) {
// ++(*this);
// }
// }
// const RTLIL::SigBit &operator*() const { return sig_iter; };
// bool operator!=(const NetlistConeInputsIter &other) const { return sig_iter != other.sig_iter; }
// bool operator==(const NetlistConeInputsIter &other) const { return sig_iter == other.sig_iter; }
// NetlistConeInputsIter &operator++()
// {
// do {
// ++sig_iter;
// if (sig_iter->empty()) {
// return *this;
// }
// } while (has_driver_cell(sig_iter));
// return *this;
// }
// };
// struct NetlistConeInputsIterable {
// const Netlist &net;
// RTLIL::SigBit sig;
// NetlistConeInputsIterable(const Netlist &net, RTLIL::SigBit sig) : net(net), sig(sig) {}
// NetlistConeInputsIter begin() { return NetlistConeInputsIter(net, sig); }
// NetlistConeInputsIter end() { return NetlistConeInputsIter(net); }
// };
} // namespace detail
detail::NetlistConeWireIterable cone(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL)
{
return detail::NetlistConeWireIterable(net, net.sigmap(sig), cell_filter = cell_filter);
}
// detail::NetlistConeInputsIterable cone_inputs(RTLIL::SigBit sig) { return NetlistConeInputsIterable(this, &sig); }
detail::NetlistConeCellIterable cell_cone(const Netlist &net, RTLIL::SigBit sig, CellTypes *cell_filter = NULL)
{
return detail::NetlistConeCellIterable(net, net.sigmap(sig), cell_filter);
}
YOSYS_NAMESPACE_END
#endif

86
passes/opt/opt_rmdff.cc
View File

@ -22,7 +22,6 @@
#include "kernel/rtlil.h"
#include "kernel/satgen.h"
#include "kernel/sigtools.h"
#include "netlist.h"
#include <stdio.h>
#include <stdlib.h>
@ -31,9 +30,8 @@ PRIVATE_NAMESPACE_BEGIN
SigMap assign_map, dff_init_map;
SigSet<RTLIL::Cell*> mux_drivers;
dict<SigBit, RTLIL::Cell*> bit2driver;
dict<SigBit, pool<SigBit>> init_attributes;
std::map<RTLIL::Module*, Netlist> netlists;
std::map<RTLIL::Module *, CellTypes> comb_filters;
bool keepdc;
bool sat;
@ -459,41 +457,46 @@ bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
dff->unsetPort("\\E");
}
if (sat && has_init) {
if (sat && has_init && (!sig_r.size() || val_init == val_rv))
{
bool removed_sigbits = false;
// Create netlist for the module if not already available
if (!netlists.count(mod)) {
netlists.emplace(mod, Netlist(mod));
comb_filters.emplace(mod, comb_cells_filt());
}
// Load netlist for the module from the pool
Netlist &net = netlists.at(mod);
ezSatPtr ez;
SatGen satgen(ez.get(), &assign_map);
pool<Cell*> sat_cells;
std::function<void(Cell*)> sat_import_cell = [&](Cell *c) {
if (!sat_cells.insert(c).second)
return;
if (!satgen.importCell(c))
return;
for (auto &conn : c->connections()) {
if (!c->input(conn.first))
continue;
for (auto bit : assign_map(conn.second))
if (bit2driver.count(bit))
sat_import_cell(bit2driver.at(bit));
}
};
// For each register bit, try to prove that it cannot change from the initial value. If so, remove it
for (int position = 0; position < GetSize(sig_d); position += 1) {
RTLIL::SigBit q_sigbit = sig_q[position];
RTLIL::SigBit d_sigbit = sig_d[position];
if ((!q_sigbit.wire) || (!d_sigbit.wire)) {
if ((!q_sigbit.wire) || (!d_sigbit.wire))
continue;
}
ezSatPtr ez;
SatGen satgen(ez.get(), &net.sigmap);
if (!bit2driver.count(d_sigbit))
continue;
// Create SAT instance only for the cells that influence the register bit combinatorially
for (const auto &cell : cell_cone(net, d_sigbit, &comb_filters.at(mod))) {
if (!satgen.importCell(cell))
log_error("Can't create SAT model for cell %s (%s)!\n", RTLIL::id2cstr(cell->name),
RTLIL::id2cstr(cell->type));
}
sat_import_cell(bit2driver.at(d_sigbit));
RTLIL::State sigbit_init_val = val_init[position];
if (sigbit_init_val != State::S0 && sigbit_init_val != State::S1)
continue;
RTLIL::Const sigbit_init_val = val_init.extract(position);
int init_sat_pi = satgen.importSigSpec(sigbit_init_val).front();
int q_sat_pi = satgen.importSigBit(q_sigbit);
int d_sat_pi = satgen.importSigBit(d_sigbit);
@ -501,24 +504,21 @@ bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
bool counter_example_found = ez->solve(ez->IFF(q_sat_pi, init_sat_pi), ez->NOT(ez->IFF(d_sat_pi, init_sat_pi)));
// If the register bit cannot change, we can replace it with a constant
if (!counter_example_found) {
if (!counter_example_found)
{
log("Setting constant %d-bit at position %d on %s (%s) from module %s.\n", sigbit_init_val ? 1 : 0,
position, log_id(dff), log_id(dff->type), log_id(mod));
RTLIL::SigSpec driver_port = net.driver_port(q_sigbit);
RTLIL::Wire *dummy_wire = mod->addWire(NEW_ID, 1);
for (auto &conn : mod->connections_)
net.sigmap(conn.first).replace(driver_port, dummy_wire, &conn.first);
remove_init_attr(driver_port);
driver_port = dummy_wire;
mod->connect(RTLIL::SigSig(q_sigbit, sigbit_init_val));
SigSpec tmp = dff->getPort("\\D");
tmp[position] = sigbit_init_val;
dff->setPort("\\D", tmp);
removed_sigbits = true;
}
}
if (removed_sigbits) {
handle_dff(mod, dff);
return true;
}
}
@ -566,8 +566,6 @@ struct OptRmdffPass : public Pass {
break;
}
extra_args(args, argidx, design);
netlists.clear();
comb_filters.clear();
for (auto module : design->selected_modules()) {
pool<SigBit> driven_bits;
@ -576,6 +574,7 @@ struct OptRmdffPass : public Pass {
assign_map.set(module);
dff_init_map.set(module);
mux_drivers.clear();
bit2driver.clear();
init_attributes.clear();
for (auto wire : module->wires())
@ -600,17 +599,21 @@ struct OptRmdffPass : public Pass {
driven_bits.insert(bit);
}
}
mux_drivers.clear();
std::vector<RTLIL::IdString> dff_list;
std::vector<RTLIL::IdString> dffsr_list;
std::vector<RTLIL::IdString> dlatch_list;
for (auto cell : module->cells())
{
for (auto &conn : cell->connections())
if (cell->output(conn.first) || !cell->known())
for (auto bit : assign_map(conn.second))
for (auto &conn : cell->connections()) {
bool is_output = cell->output(conn.first);
if (is_output || !cell->known())
for (auto bit : assign_map(conn.second)) {
if (is_output)
bit2driver[bit] = cell;
driven_bits.insert(bit);
}
}
if (cell->type == "$mux" || cell->type == "$pmux") {
if (cell->getPort("\\A").size() == cell->getPort("\\B").size())
@ -682,6 +685,7 @@ struct OptRmdffPass : public Pass {
assign_map.clear();
mux_drivers.clear();
bit2driver.clear();
init_attributes.clear();
if (total_count || total_initdrv)

25
tests/opt/opt_ff_sat.v
View File

@ -1,15 +1,12 @@
module top(
input clk,
input a,
output b
);
reg b_reg;
initial begin
b_reg <= 0;
end
assign b = b_reg;
always @(posedge clk) begin
b_reg <= a && b_reg;
end
module top (
input clk,
output reg [7:0] cnt
);
initial cnt = 0;
always @(posedge clk) begin
if (cnt < 20)
cnt <= cnt + 1;
else
cnt <= 0;
end
endmodule

1
tests/opt/opt_ff_sat.ys
View File

@ -2,3 +2,4 @@ read_verilog opt_ff_sat.v
prep -flatten
opt_rmdff -sat
synth
select -assert-count 5 t:$_DFF_P_