riscv
/
yosys
mirror of https://github.com/YosysHQ/yosys.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
yosys/passes/opt/opt_expr.cc

2000 lines
68 KiB
C++
Raw Blame History

/*
* 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/sigtools.h"
#include "kernel/celltypes.h"
#include "kernel/utils.h"
#include "kernel/log.h"
#include <stdlib.h>
#include <stdio.h>
#include <algorithm>
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
bool did_something;
void replace_undriven(RTLIL::Module *module, const CellTypes &ct)
{
SigMap sigmap(module);
SigPool driven_signals;
SigPool used_signals;
SigPool all_signals;
dict<SigBit, pair<Wire*, State>> initbits;
pool<Wire*> revisit_initwires;
for (auto cell : module->cells())
for (auto &conn : cell->connections()) {
if (!ct.cell_known(cell->type) || ct.cell_output(cell->type, conn.first))
driven_signals.add(sigmap(conn.second));
if (!ct.cell_known(cell->type) || ct.cell_input(cell->type, conn.first))
used_signals.add(sigmap(conn.second));
}
for (auto wire : module->wires()) {
if (wire->attributes.count(ID::init)) {
SigSpec sig = sigmap(wire);
Const initval = wire->attributes.at(ID::init);
for (int i = 0; i < GetSize(initval) && i < GetSize(wire); i++) {
if (initval[i] == State::S0 || initval[i] == State::S1)
initbits[sig[i]] = make_pair(wire, initval[i]);
}
}
if (wire->port_input)
driven_signals.add(sigmap(wire));
if (wire->port_output || wire->get_bool_attribute(ID::keep))
used_signals.add(sigmap(wire));
all_signals.add(sigmap(wire));
}
all_signals.del(driven_signals);
RTLIL::SigSpec undriven_signals = all_signals.export_all();
for (auto &c : undriven_signals.chunks())
{
RTLIL::SigSpec sig = c;
if (c.wire->name[0] == '$')
sig = used_signals.extract(sig);
if (sig.size() == 0)
continue;
Const val(RTLIL::State::Sx, GetSize(sig));
for (int i = 0; i < GetSize(sig); i++) {
SigBit bit = sigmap(sig[i]);
auto cursor = initbits.find(bit);
if (cursor != initbits.end()) {
revisit_initwires.insert(cursor->second.first);
val[i] = cursor->second.second;
}
}
log_debug("Setting undriven signal in %s to constant: %s = %s\n", log_id(module), log_signal(sig), log_signal(val));
module->connect(sig, val);
did_something = true;
}
if (!revisit_initwires.empty())
{
SigMap sm2(module);
for (auto wire : revisit_initwires) {
SigSpec sig = sm2(wire);
Const initval = wire->attributes.at(ID::init);
for (int i = 0; i < GetSize(initval) && i < GetSize(wire); i++) {
if (SigBit(initval[i]) == sig[i])
initval[i] = State::Sx;
}
if (initval.is_fully_undef()) {
log_debug("Removing init attribute from %s/%s.\n", log_id(module), log_id(wire));
wire->attributes.erase(ID::init);
did_something = true;
} else if (initval != wire->attributes.at(ID::init)) {
log_debug("Updating init attribute on %s/%s: %s\n", log_id(module), log_id(wire), log_signal(initval));
wire->attributes[ID::init] = initval;
did_something = true;
}
}
}
}
void replace_cell(SigMap &assign_map, RTLIL::Module *module, RTLIL::Cell *cell,
const std::string &info YS_ATTRIBUTE(unused), IdString out_port, RTLIL::SigSpec out_val)
{
RTLIL::SigSpec Y = cell->getPort(out_port);
out_val.extend_u0(Y.size(), false);
log_debug("Replacing %s cell `%s' (%s) in module `%s' with constant driver `%s = %s'.\n",
cell->type.c_str(), cell->name.c_str(), info.c_str(),
module->name.c_str(), log_signal(Y), log_signal(out_val));
// log_cell(cell);
assign_map.add(Y, out_val);
module->connect(Y, out_val);
module->remove(cell);
did_something = true;
}
bool group_cell_inputs(RTLIL::Module *module, RTLIL::Cell *cell, bool commutative, SigMap &sigmap)
{
IdString b_name = cell->hasPort(ID::B) ? ID::B : ID::A;
bool a_signed = cell->parameters.at(ID::A_SIGNED).as_bool();
bool b_signed = cell->parameters.at(b_name.str() + "_SIGNED").as_bool();
RTLIL::SigSpec sig_a = sigmap(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = sigmap(cell->getPort(b_name));
RTLIL::SigSpec sig_y = sigmap(cell->getPort(ID::Y));
sig_a.extend_u0(sig_y.size(), a_signed);
sig_b.extend_u0(sig_y.size(), b_signed);
std::vector<RTLIL::SigBit> bits_a = sig_a, bits_b = sig_b, bits_y = sig_y;
enum { GRP_DYN, GRP_CONST_A, GRP_CONST_B, GRP_CONST_AB, GRP_N };
std::map<std::pair<RTLIL::SigBit, RTLIL::SigBit>, std::set<RTLIL::SigBit>> grouped_bits[GRP_N];
for (int i = 0; i < GetSize(bits_y); i++)
{
int group_idx = GRP_DYN;
RTLIL::SigBit bit_a = bits_a[i], bit_b = bits_b[i];
if (cell->type == ID($or) && (bit_a == RTLIL::State::S1 || bit_b == RTLIL::State::S1))
bit_a = bit_b = RTLIL::State::S1;
if (cell->type == ID($and) && (bit_a == RTLIL::State::S0 || bit_b == RTLIL::State::S0))
bit_a = bit_b = RTLIL::State::S0;
if (bit_a.wire == NULL && bit_b.wire == NULL)
group_idx = GRP_CONST_AB;
else if (bit_a.wire == NULL)
group_idx = GRP_CONST_A;
else if (bit_b.wire == NULL && commutative)
group_idx = GRP_CONST_A, std::swap(bit_a, bit_b);
else if (bit_b.wire == NULL)
group_idx = GRP_CONST_B;
grouped_bits[group_idx][std::pair<RTLIL::SigBit, RTLIL::SigBit>(bit_a, bit_b)].insert(bits_y[i]);
}
for (int i = 0; i < GRP_N; i++)
if (GetSize(grouped_bits[i]) == GetSize(bits_y))
return false;
log_debug("Replacing %s cell `%s' in module `%s' with cells using grouped bits:\n",
log_id(cell->type), log_id(cell), log_id(module));
for (int i = 0; i < GRP_N; i++)
{
if (grouped_bits[i].empty())
continue;
RTLIL::Wire *new_y = module->addWire(NEW_ID, GetSize(grouped_bits[i]));
RTLIL::SigSpec new_a, new_b;
RTLIL::SigSig new_conn;
for (auto &it : grouped_bits[i]) {
for (auto &bit : it.second) {
new_conn.first.append(bit);
new_conn.second.append(RTLIL::SigBit(new_y, new_a.size()));
}
new_a.append(it.first.first);
new_b.append(it.first.second);
}
if (cell->type.in(ID($and), ID($or)) && i == GRP_CONST_A) {
log_debug(" Direct Connection: %s (%s with %s)\n", log_signal(new_b), log_id(cell->type), log_signal(new_a));
module->connect(new_y, new_b);
module->connect(new_conn);
continue;
}
RTLIL::Cell *c = module->addCell(NEW_ID, cell->type);
c->setPort(ID::A, new_a);
c->parameters[ID::A_WIDTH] = new_a.size();
c->parameters[ID::A_SIGNED] = false;
if (b_name == ID::B) {
c->setPort(ID::B, new_b);
c->parameters[ID::B_WIDTH] = new_b.size();
c->parameters[ID::B_SIGNED] = false;
}
c->setPort(ID::Y, new_y);
c->parameters[ID::Y_WIDTH] = new_y->width;
c->check();
module->connect(new_conn);
log_debug(" New cell `%s': A=%s", log_id(c), log_signal(new_a));
if (b_name == ID::B)
log_debug(", B=%s", log_signal(new_b));
log_debug("\n");
}
cover_list("opt.opt_expr.fine.group", "$not", "$pos", "$and", "$or", "$xor", "$xnor", cell->type.str());
module->remove(cell);
did_something = true;
return true;
}
void handle_polarity_inv(Cell *cell, IdString port, IdString param, const SigMap &assign_map, const dict<RTLIL::SigSpec, RTLIL::SigSpec> &invert_map)
{
SigSpec sig = assign_map(cell->getPort(port));
if (invert_map.count(sig)) {
log_debug("Inverting %s of %s cell `%s' in module `%s': %s -> %s\n",
log_id(port), log_id(cell->type), log_id(cell), log_id(cell->module),
log_signal(sig), log_signal(invert_map.at(sig)));
cell->setPort(port, (invert_map.at(sig)));
cell->setParam(param, !cell->getParam(param).as_bool());
}
}
void handle_clkpol_celltype_swap(Cell *cell, string type1, string type2, IdString port, const SigMap &assign_map, const dict<RTLIL::SigSpec, RTLIL::SigSpec> &invert_map)
{
log_assert(GetSize(type1) == GetSize(type2));
string cell_type = cell->type.str();
if (GetSize(type1) != GetSize(cell_type))
return;
for (int i = 0; i < GetSize(type1); i++) {
log_assert((type1[i] == '?') == (type2[i] == '?'));
if (type1[i] == '?') {
if (cell_type[i] != '0' && cell_type[i] != '1' && cell_type[i] != 'N' && cell_type[i] != 'P')
return;
type1[i] = cell_type[i];
type2[i] = cell_type[i];
}
}
if (cell->type.in(type1, type2)) {
SigSpec sig = assign_map(cell->getPort(port));
if (invert_map.count(sig)) {
log_debug("Inverting %s of %s cell `%s' in module `%s': %s -> %s\n",
log_id(port), log_id(cell->type), log_id(cell), log_id(cell->module),
log_signal(sig), log_signal(invert_map.at(sig)));
cell->setPort(port, (invert_map.at(sig)));
cell->type = cell->type == type1 ? type2 : type1;
}
}
}
bool is_one_or_minus_one(const Const &value, bool is_signed, bool &is_negative)
{
bool all_bits_one = true;
bool last_bit_one = true;
if (GetSize(value.bits) < 1)
return false;
if (GetSize(value.bits) == 1) {
if (value.bits[0] != State::S1)
return false;
if (is_signed)
is_negative = true;
return true;
}
for (int i = 0; i < GetSize(value.bits); i++) {
if (value.bits[i] != State::S1)
all_bits_one = false;
if (value.bits[i] != (i ? State::S0 : State::S1))
last_bit_one = false;
}
if (all_bits_one && is_signed) {
is_negative = true;
return true;
}
return last_bit_one;
}
int get_highest_hot_index(RTLIL::SigSpec signal)
{
for (int i = GetSize(signal) - 1; i >= 0; i--)
{
if (signal[i] == RTLIL::State::S0)
continue;
if (signal[i] == RTLIL::State::S1)
return i;
break;
}
return -1;
}
// if the signal has only one bit set, return the index of that bit.
// otherwise return -1
int get_onehot_bit_index(RTLIL::SigSpec signal)
{
int bit_index = -1;
for (int i = 0; i < GetSize(signal); i++)
{
if (signal[i] == RTLIL::State::S0)
continue;
if (signal[i] != RTLIL::State::S1)
return -1;
if (bit_index != -1)
return -1;
bit_index = i;
}
return bit_index;
}
void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool consume_x, bool mux_undef, bool mux_bool, bool do_fine, bool keepdc, bool clkinv)
{
if (!design->selected(module))
return;
CellTypes ct_combinational;
ct_combinational.setup_internals();
ct_combinational.setup_stdcells();
SigMap assign_map(module);
dict<RTLIL::SigSpec, RTLIL::SigSpec> invert_map;
TopoSort<RTLIL::Cell*, RTLIL::IdString::compare_ptr_by_name<RTLIL::Cell>> cells;
dict<RTLIL::Cell*, std::set<RTLIL::SigBit>> cell_to_inbit;
dict<RTLIL::SigBit, std::set<RTLIL::Cell*>> outbit_to_cell;
for (auto cell : module->cells())
if (design->selected(module, cell) && cell->type[0] == '$') {
if (cell->type.in(ID($_NOT_), ID($not), ID($logic_not)) &&
GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::Y)) == 1)
invert_map[assign_map(cell->getPort(ID::Y))] = assign_map(cell->getPort(ID::A));
if (cell->type.in(ID($mux), ID($_MUX_)) &&
cell->getPort(ID::A) == SigSpec(State::S1) && cell->getPort(ID::B) == SigSpec(State::S0))
invert_map[assign_map(cell->getPort(ID::Y))] = assign_map(cell->getPort(ID::S));
if (ct_combinational.cell_known(cell->type))
for (auto &conn : cell->connections()) {
RTLIL::SigSpec sig = assign_map(conn.second);
sig.remove_const();
if (ct_combinational.cell_input(cell->type, conn.first))
cell_to_inbit[cell].insert(sig.begin(), sig.end());
if (ct_combinational.cell_output(cell->type, conn.first))
for (auto &bit : sig)
outbit_to_cell[bit].insert(cell);
}
cells.node(cell);
}
for (auto &it_right : cell_to_inbit)
for (auto &it_sigbit : it_right.second)
for (auto &it_left : outbit_to_cell[it_sigbit])
cells.edge(it_left, it_right.first);
cells.sort();
for (auto cell : cells.sorted)
{
#define ACTION_DO(_p_, _s_) do { cover("opt.opt_expr.action_" S__LINE__); replace_cell(assign_map, module, cell, input.as_string(), _p_, _s_); goto next_cell; } while (0)
#define ACTION_DO_Y(_v_) ACTION_DO(ID::Y, RTLIL::SigSpec(RTLIL::State::S ## _v_))
if (clkinv)
{
if (cell->type.in(ID($dff), ID($dffe), ID($dffsr), ID($adff), ID($fsm), ID($memrd), ID($memwr)))
handle_polarity_inv(cell, ID::CLK, ID::CLK_POLARITY, assign_map, invert_map);
if (cell->type.in(ID($sr), ID($dffsr), ID($dlatchsr))) {
handle_polarity_inv(cell, ID::SET, ID::SET_POLARITY, assign_map, invert_map);
handle_polarity_inv(cell, ID::CLR, ID::CLR_POLARITY, assign_map, invert_map);
}
if (cell->type.in(ID($dffe), ID($dlatch), ID($dlatchsr)))
handle_polarity_inv(cell, ID::EN, ID::EN_POLARITY, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_SR_N?_", "$_SR_P?_", ID::S, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_SR_?N_", "$_SR_?P_", ID::R, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFF_N_", "$_DFF_P_", ID::C, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFFE_N?_", "$_DFFE_P?_", ID::C, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFFE_?N_", "$_DFFE_?P_", ID::E, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFF_N??_", "$_DFF_P??_", ID::C, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFF_?N?_", "$_DFF_?P?_", ID::R, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFFSR_N??_", "$_DFFSR_P??_", ID::C, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFFSR_?N?_", "$_DFFSR_?P?_", ID::S, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DFFSR_??N_", "$_DFFSR_??P_", ID::R, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DLATCH_N_", "$_DLATCH_P_", ID::E, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DLATCHSR_N??_", "$_DLATCHSR_P??_", ID::E, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DLATCHSR_?N?_", "$_DLATCHSR_?P?_", ID::S, assign_map, invert_map);
handle_clkpol_celltype_swap(cell, "$_DLATCHSR_??N_", "$_DLATCHSR_??P_", ID::R, assign_map, invert_map);
}
bool detect_const_and = false;
bool detect_const_or = false;
if (cell->type.in(ID($reduce_and), ID($_AND_)))
detect_const_and = true;
if (cell->type.in(ID($and), ID($logic_and)) && GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::B)) == 1 && !cell->getParam(ID::A_SIGNED).as_bool())
detect_const_and = true;
if (cell->type.in(ID($reduce_or), ID($reduce_bool), ID($_OR_)))
detect_const_or = true;
if (cell->type.in(ID($or), ID($logic_or)) && GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::B)) == 1 && !cell->getParam(ID::A_SIGNED).as_bool())
detect_const_or = true;
if (detect_const_and || detect_const_or)
{
pool<SigBit> input_bits = assign_map(cell->getPort(ID::A)).to_sigbit_pool();
bool found_zero = false, found_one = false, found_undef = false, found_inv = false, many_conconst = false;
SigBit non_const_input = State::Sm;
if (cell->hasPort(ID::B)) {
vector<SigBit> more_bits = assign_map(cell->getPort(ID::B)).to_sigbit_vector();
input_bits.insert(more_bits.begin(), more_bits.end());
}
for (auto bit : input_bits) {
if (bit.wire) {
if (invert_map.count(bit) && input_bits.count(invert_map.at(bit)))
found_inv = true;
if (non_const_input != State::Sm)
many_conconst = true;
non_const_input = many_conconst ? State::Sm : bit;
} else {
if (bit == State::S0)
found_zero = true;
else if (bit == State::S1)
found_one = true;
else
found_undef = true;
}
}
if (detect_const_and && (found_zero || found_inv)) {
cover("opt.opt_expr.const_and");
replace_cell(assign_map, module, cell, "const_and", ID::Y, RTLIL::State::S0);
goto next_cell;
}
if (detect_const_or && (found_one || found_inv)) {
cover("opt.opt_expr.const_or");
replace_cell(assign_map, module, cell, "const_or", ID::Y, RTLIL::State::S1);
goto next_cell;
}
if (non_const_input != State::Sm && !found_undef) {
cover("opt.opt_expr.and_or_buffer");
replace_cell(assign_map, module, cell, "and_or_buffer", ID::Y, non_const_input);
goto next_cell;
}
}
if (cell->type.in(ID($_XOR_), ID($_XNOR_)) || (cell->type.in(ID($xor), ID($xnor)) && GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::B)) == 1 && !cell->getParam(ID::A_SIGNED).as_bool()))
{
SigBit sig_a = assign_map(cell->getPort(ID::A));
SigBit sig_b = assign_map(cell->getPort(ID::B));
if (!sig_a.wire)
std::swap(sig_a, sig_b);
if (sig_b == State::S0 || sig_b == State::S1) {
if (cell->type.in(ID($xor), ID($_XOR_))) {
cover("opt.opt_expr.xor_buffer");
SigSpec sig_y;
if (cell->type == ID($xor))
sig_y = (sig_b == State::S1 ? module->Not(NEW_ID, sig_a).as_bit() : sig_a);
else if (cell->type == ID($_XOR_))
sig_y = (sig_b == State::S1 ? module->NotGate(NEW_ID, sig_a) : sig_a);
else log_abort();
replace_cell(assign_map, module, cell, "xor_buffer", ID::Y, sig_y);
goto next_cell;
}
if (cell->type.in(ID($xnor), ID($_XNOR_))) {
cover("opt.opt_expr.xnor_buffer");
SigSpec sig_y;
if (cell->type == ID($xnor)) {
sig_y = (sig_b == State::S1 ? sig_a : module->Not(NEW_ID, sig_a).as_bit());
int width = cell->getParam(ID::Y_WIDTH).as_int();
sig_y.append(RTLIL::Const(State::S1, width-1));
}
else if (cell->type == ID($_XNOR_))
sig_y = (sig_b == State::S1 ? sig_a : module->NotGate(NEW_ID, sig_a));
else log_abort();
replace_cell(assign_map, module, cell, "xnor_buffer", ID::Y, sig_y);
goto next_cell;
}
log_abort();
}
}
if (cell->type.in(ID($reduce_and), ID($reduce_or), ID($reduce_bool), ID($reduce_xor), ID($reduce_xnor), ID($neg)) &&
GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::Y)) == 1)
{
if (cell->type == ID($reduce_xnor)) {
cover("opt.opt_expr.reduce_xnor_not");
log_debug("Replacing %s cell `%s' in module `%s' with $not cell.\n",
log_id(cell->type), log_id(cell->name), log_id(module));
cell->type = ID($not);
did_something = true;
} else {
cover("opt.opt_expr.unary_buffer");
replace_cell(assign_map, module, cell, "unary_buffer", ID::Y, cell->getPort(ID::A));
}
goto next_cell;
}
if (do_fine)
{
if (cell->type.in(ID($not), ID($pos), ID($and), ID($or), ID($xor), ID($xnor)))
if (group_cell_inputs(module, cell, true, assign_map))
goto next_cell;
if (cell->type.in(ID($logic_not), ID($logic_and), ID($logic_or), ID($reduce_or), ID($reduce_and), ID($reduce_bool)))
{
SigBit neutral_bit = cell->type == ID($reduce_and) ? State::S1 : State::S0;
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec new_sig_a;
for (auto bit : sig_a)
if (bit != neutral_bit) new_sig_a.append(bit);
if (GetSize(new_sig_a) == 0)
new_sig_a.append(neutral_bit);
if (GetSize(new_sig_a) < GetSize(sig_a)) {
cover_list("opt.opt_expr.fine.neutral_A", "$logic_not", "$logic_and", "$logic_or", "$reduce_or", "$reduce_and", "$reduce_bool", cell->type.str());
log_debug("Replacing port A of %s cell `%s' in module `%s' with shorter expression: %s -> %s\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), log_signal(sig_a), log_signal(new_sig_a));
cell->setPort(ID::A, new_sig_a);
cell->parameters.at(ID::A_WIDTH) = GetSize(new_sig_a);
did_something = true;
}
}
if (cell->type.in(ID($logic_and), ID($logic_or)))
{
SigBit neutral_bit = State::S0;
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::SigSpec new_sig_b;
for (auto bit : sig_b)
if (bit != neutral_bit) new_sig_b.append(bit);
if (GetSize(new_sig_b) == 0)
new_sig_b.append(neutral_bit);
if (GetSize(new_sig_b) < GetSize(sig_b)) {
cover_list("opt.opt_expr.fine.neutral_B", "$logic_and", "$logic_or", cell->type.str());
log_debug("Replacing port B of %s cell `%s' in module `%s' with shorter expression: %s -> %s\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), log_signal(sig_b), log_signal(new_sig_b));
cell->setPort(ID::B, new_sig_b);
cell->parameters.at(ID::B_WIDTH) = GetSize(new_sig_b);
did_something = true;
}
}
if (cell->type == ID($reduce_and))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::State new_a = RTLIL::State::S1;
for (auto &bit : sig_a.to_sigbit_vector())
if (bit == RTLIL::State::Sx) {
if (new_a == RTLIL::State::S1)
new_a = RTLIL::State::Sx;
} else if (bit == RTLIL::State::S0) {
new_a = RTLIL::State::S0;
break;
} else if (bit.wire != NULL) {
new_a = RTLIL::State::Sm;
}
if (new_a != RTLIL::State::Sm && RTLIL::SigSpec(new_a) != sig_a) {
cover("opt.opt_expr.fine.$reduce_and");
log_debug("Replacing port A of %s cell `%s' in module `%s' with constant driver: %s -> %s\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), log_signal(sig_a), log_signal(new_a));
cell->setPort(ID::A, sig_a = new_a);
cell->parameters.at(ID::A_WIDTH) = 1;
did_something = true;
}
}
if (cell->type.in(ID($logic_not), ID($logic_and), ID($logic_or), ID($reduce_or), ID($reduce_bool)))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::State new_a = RTLIL::State::S0;
for (auto &bit : sig_a.to_sigbit_vector())
if (bit == RTLIL::State::Sx) {
if (new_a == RTLIL::State::S0)
new_a = RTLIL::State::Sx;
} else if (bit == RTLIL::State::S1) {
new_a = RTLIL::State::S1;
break;
} else if (bit.wire != NULL) {
new_a = RTLIL::State::Sm;
}
if (new_a != RTLIL::State::Sm && RTLIL::SigSpec(new_a) != sig_a) {
cover_list("opt.opt_expr.fine.A", "$logic_not", "$logic_and", "$logic_or", "$reduce_or", "$reduce_bool", cell->type.str());
log_debug("Replacing port A of %s cell `%s' in module `%s' with constant driver: %s -> %s\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), log_signal(sig_a), log_signal(new_a));
cell->setPort(ID::A, sig_a = new_a);
cell->parameters.at(ID::A_WIDTH) = 1;
did_something = true;
}
}
if (cell->type.in(ID($logic_and), ID($logic_or)))
{
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::State new_b = RTLIL::State::S0;
for (auto &bit : sig_b.to_sigbit_vector())
if (bit == RTLIL::State::Sx) {
if (new_b == RTLIL::State::S0)
new_b = RTLIL::State::Sx;
} else if (bit == RTLIL::State::S1) {
new_b = RTLIL::State::S1;
break;
} else if (bit.wire != NULL) {
new_b = RTLIL::State::Sm;
}
if (new_b != RTLIL::State::Sm && RTLIL::SigSpec(new_b) != sig_b) {
cover_list("opt.opt_expr.fine.B", "$logic_and", "$logic_or", cell->type.str());
log_debug("Replacing port B of %s cell `%s' in module `%s' with constant driver: %s -> %s\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), log_signal(sig_b), log_signal(new_b));
cell->setPort(ID::B, sig_b = new_b);
cell->parameters.at(ID::B_WIDTH) = 1;
did_something = true;
}
}
if (cell->type.in(ID($add), ID($sub)))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::SigSpec sig_y = cell->getPort(ID::Y);
bool is_signed = cell->getParam(ID::A_SIGNED).as_bool();
bool sub = cell->type == ID($sub);
int minsz = GetSize(sig_y);
minsz = std::min(minsz, GetSize(sig_a));
minsz = std::min(minsz, GetSize(sig_b));
int i;
for (i = 0; i < minsz; i++) {
RTLIL::SigBit b = sig_b[i];
RTLIL::SigBit a = sig_a[i];
if (b == State::S0)
module->connect(sig_y[i], a);
else if (sub && b == State::S1 && a == State::S1)
module->connect(sig_y[i], State::S0);
else if (!sub && a == State::S0)
module->connect(sig_y[i], b);
else
break;
}
if (i > 0) {
cover_list("opt.opt_expr.fine", "$add", "$sub", cell->type.str());
log_debug("Stripping %d LSB bits of %s cell %s in module %s.\n", i, log_id(cell->type), log_id(cell), log_id(module));
SigSpec new_a = sig_a.extract_end(i);
SigSpec new_b = sig_b.extract_end(i);
if (new_a.empty() && is_signed)
new_a = sig_a[i-1];
if (new_b.empty() && is_signed)
new_b = sig_b[i-1];
cell->setPort(ID::A, new_a);
cell->setPort(ID::B, new_b);
cell->setPort(ID::Y, sig_y.extract_end(i));
cell->fixup_parameters();
did_something = true;
}
}
if (cell->type == ID($alu))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::SigBit sig_ci = assign_map(cell->getPort(ID::CI));
RTLIL::SigBit sig_bi = assign_map(cell->getPort(ID::BI));
RTLIL::SigSpec sig_x = cell->getPort(ID::X);
RTLIL::SigSpec sig_y = cell->getPort(ID::Y);
RTLIL::SigSpec sig_co = cell->getPort(ID::CO);
bool is_signed = cell->getParam(ID::A_SIGNED).as_bool();
if (sig_bi != State::S0 && sig_bi != State::S1)
goto skip_fine_alu;
if (sig_ci != State::S0 && sig_ci != State::S1)
goto skip_fine_alu;
bool bi = sig_bi == State::S1;
bool ci = sig_ci == State::S1;
int minsz = GetSize(sig_y);
minsz = std::min(minsz, GetSize(sig_a));
minsz = std::min(minsz, GetSize(sig_b));
int i;
for (i = 0; i < minsz; i++) {
RTLIL::SigBit b = sig_b[i];
RTLIL::SigBit a = sig_a[i];
if (b == ((bi ^ ci) ? State::S1 : State::S0)) {
module->connect(sig_y[i], a);
module->connect(sig_x[i], ci ? module->Not(NEW_ID, a).as_bit() : a);
module->connect(sig_co[i], ci ? State::S1 : State::S0);
}
else if (a == (ci ? State::S1 : State::S0)) {
module->connect(sig_y[i], bi ? module->Not(NEW_ID, b).as_bit() : b);
module->connect(sig_x[i], (bi ^ ci) ? module->Not(NEW_ID, b).as_bit() : b);
module->connect(sig_co[i], ci ? State::S1 : State::S0);
}
else
break;
}
if (i > 0) {
cover("opt.opt_expr.fine.$alu");
log_debug("Stripping %d LSB bits of %s cell %s in module %s.\n", i, log_id(cell->type), log_id(cell), log_id(module));
SigSpec new_a = sig_a.extract_end(i);
SigSpec new_b = sig_b.extract_end(i);
if (new_a.empty() && is_signed)
new_a = sig_a[i-1];
if (new_b.empty() && is_signed)
new_b = sig_b[i-1];
cell->setPort(ID::A, new_a);
cell->setPort(ID::B, new_b);
cell->setPort(ID::X, sig_x.extract_end(i));
cell->setPort(ID::Y, sig_y.extract_end(i));
cell->setPort(ID::CO, sig_co.extract_end(i));
cell->fixup_parameters();
did_something = true;
}
}
}
skip_fine_alu:
if (cell->type.in(ID($reduce_xor), ID($reduce_xnor), ID($shift), ID($shiftx), ID($shl), ID($shr), ID($sshl), ID($sshr),
ID($lt), ID($le), ID($ge), ID($gt), ID($neg), ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($pow)))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = cell->hasPort(ID::B) ? assign_map(cell->getPort(ID::B)) : RTLIL::SigSpec();
if (cell->type.in(ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx)))
sig_a = RTLIL::SigSpec();
for (auto &bit : sig_a.to_sigbit_vector())
if (bit == RTLIL::State::Sx)
goto found_the_x_bit;
for (auto &bit : sig_b.to_sigbit_vector())
if (bit == RTLIL::State::Sx)
goto found_the_x_bit;
if (0) {
found_the_x_bit:
cover_list("opt.opt_expr.xbit", "$reduce_xor", "$reduce_xnor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx",
"$lt", "$le", "$ge", "$gt", "$neg", "$add", "$sub", "$mul", "$div", "$mod", "$pow", cell->type.str());
if (cell->type.in(ID($reduce_xor), ID($reduce_xnor), ID($lt), ID($le), ID($ge), ID($gt)))
replace_cell(assign_map, module, cell, "x-bit in input", ID::Y, RTLIL::State::Sx);
else
replace_cell(assign_map, module, cell, "x-bit in input", ID::Y, RTLIL::SigSpec(RTLIL::State::Sx, GetSize(cell->getPort(ID::Y))));
goto next_cell;
}
}
if (cell->type.in(ID($shiftx), ID($shift))) {
SigSpec sig_a = assign_map(cell->getPort(ID::A));
int width;
bool trim_x = cell->type == ID($shiftx) || !keepdc;
bool trim_0 = cell->type == ID($shift);
for (width = GetSize(sig_a); width > 1; width--) {
if ((trim_x && sig_a[width-1] == State::Sx) ||
(trim_0 && sig_a[width-1] == State::S0))
continue;
break;
}
if (width < GetSize(sig_a)) {
cover_list("opt.opt_expr.trim", "$shiftx", "$shift", cell->type.str());
sig_a.remove(width, GetSize(sig_a)-width);
cell->setPort(ID::A, sig_a);
cell->setParam(ID::A_WIDTH, width);
did_something = true;
goto next_cell;
}
}
if (cell->type.in(ID($_NOT_), ID($not), ID($logic_not)) && GetSize(cell->getPort(ID::Y)) == 1 &&
invert_map.count(assign_map(cell->getPort(ID::A))) != 0) {
cover_list("opt.opt_expr.invert.double", "$_NOT_", "$not", "$logic_not", cell->type.str());
replace_cell(assign_map, module, cell, "double_invert", ID::Y, invert_map.at(assign_map(cell->getPort(ID::A))));
goto next_cell;
}
if (cell->type.in(ID($_MUX_), ID($mux)) && invert_map.count(assign_map(cell->getPort(ID::S))) != 0) {
cover_list("opt.opt_expr.invert.muxsel", "$_MUX_", "$mux", cell->type.str());
log_debug("Optimizing away select inverter for %s cell `%s' in module `%s'.\n", log_id(cell->type), log_id(cell), log_id(module));
RTLIL::SigSpec tmp = cell->getPort(ID::A);
cell->setPort(ID::A, cell->getPort(ID::B));
cell->setPort(ID::B, tmp);
cell->setPort(ID::S, invert_map.at(assign_map(cell->getPort(ID::S))));
did_something = true;
goto next_cell;
}
if (cell->type == ID($_NOT_)) {
RTLIL::SigSpec input = cell->getPort(ID::A);
assign_map.apply(input);
if (input.match("1")) ACTION_DO_Y(0);
if (input.match("0")) ACTION_DO_Y(1);
if (input.match("*")) ACTION_DO_Y(x);
}
if (cell->type == ID($_AND_)) {
RTLIL::SigSpec input;
input.append(cell->getPort(ID::B));
input.append(cell->getPort(ID::A));
assign_map.apply(input);
if (input.match(" 0")) ACTION_DO_Y(0);
if (input.match("0 ")) ACTION_DO_Y(0);
if (input.match("11")) ACTION_DO_Y(1);
if (input.match("**")) ACTION_DO_Y(x);
if (input.match("1*")) ACTION_DO_Y(x);
if (input.match("*1")) ACTION_DO_Y(x);
if (consume_x) {
if (input.match(" *")) ACTION_DO_Y(0);
if (input.match("* ")) ACTION_DO_Y(0);
}
if (input.match(" 1")) ACTION_DO(ID::Y, input.extract(1, 1));
if (input.match("1 ")) ACTION_DO(ID::Y, input.extract(0, 1));
}
if (cell->type == ID($_OR_)) {
RTLIL::SigSpec input;
input.append(cell->getPort(ID::B));
input.append(cell->getPort(ID::A));
assign_map.apply(input);
if (input.match(" 1")) ACTION_DO_Y(1);
if (input.match("1 ")) ACTION_DO_Y(1);
if (input.match("00")) ACTION_DO_Y(0);
if (input.match("**")) ACTION_DO_Y(x);
if (input.match("0*")) ACTION_DO_Y(x);
if (input.match("*0")) ACTION_DO_Y(x);
if (consume_x) {
if (input.match(" *")) ACTION_DO_Y(1);
if (input.match("* ")) ACTION_DO_Y(1);
}
if (input.match(" 0")) ACTION_DO(ID::Y, input.extract(1, 1));
if (input.match("0 ")) ACTION_DO(ID::Y, input.extract(0, 1));
}
if (cell->type == ID($_XOR_)) {
RTLIL::SigSpec input;
input.append(cell->getPort(ID::B));
input.append(cell->getPort(ID::A));
assign_map.apply(input);
if (input.match("00")) ACTION_DO_Y(0);
if (input.match("01")) ACTION_DO_Y(1);
if (input.match("10")) ACTION_DO_Y(1);
if (input.match("11")) ACTION_DO_Y(0);
if (input.match(" *")) ACTION_DO_Y(x);
if (input.match("* ")) ACTION_DO_Y(x);
}
if (cell->type == ID($_MUX_)) {
RTLIL::SigSpec input;
input.append(cell->getPort(ID::S));
input.append(cell->getPort(ID::B));
input.append(cell->getPort(ID::A));
assign_map.apply(input);
if (input.extract(2, 1) == input.extract(1, 1))
ACTION_DO(ID::Y, input.extract(2, 1));
if (input.match(" 0")) ACTION_DO(ID::Y, input.extract(2, 1));
if (input.match(" 1")) ACTION_DO(ID::Y, input.extract(1, 1));
if (input.match("01 ")) ACTION_DO(ID::Y, input.extract(0, 1));
if (input.match("10 ")) {
cover("opt.opt_expr.mux_to_inv");
cell->type = ID($_NOT_);
cell->setPort(ID::A, input.extract(0, 1));
cell->unsetPort(ID::B);
cell->unsetPort(ID::S);
goto next_cell;
}
if (input.match("11 ")) ACTION_DO_Y(1);
if (input.match("00 ")) ACTION_DO_Y(0);
if (input.match("** ")) ACTION_DO_Y(x);
if (input.match("01*")) ACTION_DO_Y(x);
if (input.match("10*")) ACTION_DO_Y(x);
if (mux_undef) {
if (input.match("* ")) ACTION_DO(ID::Y, input.extract(1, 1));
if (input.match(" * ")) ACTION_DO(ID::Y, input.extract(2, 1));
if (input.match(" *")) ACTION_DO(ID::Y, input.extract(2, 1));
}
}
if (cell->type.in(ID($_TBUF_), ID($tribuf))) {
RTLIL::SigSpec input = cell->getPort(cell->type == ID($_TBUF_) ? ID::E : ID::EN);
RTLIL::SigSpec a = cell->getPort(ID::A);
assign_map.apply(input);
assign_map.apply(a);
if (input == State::S1)
ACTION_DO(ID::Y, cell->getPort(ID::A));
if (input == State::S0 && !a.is_fully_undef()) {
cover("opt.opt_expr.action_" S__LINE__);
log_debug("Replacing data input of %s cell `%s' in module `%s' with constant undef.\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str());
cell->setPort(ID::A, SigSpec(State::Sx, GetSize(a)));
did_something = true;
goto next_cell;
}
}
if (cell->type.in(ID($eq), ID($ne), ID($eqx), ID($nex)))
{
RTLIL::SigSpec a = cell->getPort(ID::A);
RTLIL::SigSpec b = cell->getPort(ID::B);
if (cell->parameters[ID::A_WIDTH].as_int() != cell->parameters[ID::B_WIDTH].as_int()) {
int width = max(cell->parameters[ID::A_WIDTH].as_int(), cell->parameters[ID::B_WIDTH].as_int());
a.extend_u0(width, cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool());
b.extend_u0(width, cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool());
}
RTLIL::SigSpec new_a, new_b;
log_assert(GetSize(a) == GetSize(b));
for (int i = 0; i < GetSize(a); i++) {
if (a[i].wire == NULL && b[i].wire == NULL && a[i] != b[i] && a[i].data <= RTLIL::State::S1 && b[i].data <= RTLIL::State::S1) {
cover_list("opt.opt_expr.eqneq.isneq", "$eq", "$ne", "$eqx", "$nex", cell->type.str());
RTLIL::SigSpec new_y = RTLIL::SigSpec(cell->type.in(ID($eq), ID($eqx)) ? RTLIL::State::S0 : RTLIL::State::S1);
new_y.extend_u0(cell->parameters[ID::Y_WIDTH].as_int(), false);
replace_cell(assign_map, module, cell, "isneq", ID::Y, new_y);
goto next_cell;
}
if (a[i] == b[i])
continue;
new_a.append(a[i]);
new_b.append(b[i]);
}
if (new_a.size() == 0) {
cover_list("opt.opt_expr.eqneq.empty", "$eq", "$ne", "$eqx", "$nex", cell->type.str());
RTLIL::SigSpec new_y = RTLIL::SigSpec(cell->type.in(ID($eq), ID($eqx)) ? RTLIL::State::S1 : RTLIL::State::S0);
new_y.extend_u0(cell->parameters[ID::Y_WIDTH].as_int(), false);
replace_cell(assign_map, module, cell, "empty", ID::Y, new_y);
goto next_cell;
}
if (new_a.size() < a.size() || new_b.size() < b.size()) {
cover_list("opt.opt_expr.eqneq.resize", "$eq", "$ne", "$eqx", "$nex", cell->type.str());
cell->setPort(ID::A, new_a);
cell->setPort(ID::B, new_b);
cell->parameters[ID::A_WIDTH] = new_a.size();
cell->parameters[ID::B_WIDTH] = new_b.size();
}
}
if (cell->type.in(ID($eq), ID($ne)) && cell->parameters[ID::Y_WIDTH].as_int() == 1 &&
cell->parameters[ID::A_WIDTH].as_int() == 1 && cell->parameters[ID::B_WIDTH].as_int() == 1)
{
RTLIL::SigSpec a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
if (a.is_fully_const() && !b.is_fully_const()) {
cover_list("opt.opt_expr.eqneq.swapconst", "$eq", "$ne", cell->type.str());
cell->setPort(ID::A, b);
cell->setPort(ID::B, a);
std::swap(a, b);
}
if (b.is_fully_const()) {
if (b.is_fully_undef()) {
RTLIL::SigSpec input = b;
ACTION_DO(ID::Y, Const(State::Sx, GetSize(cell->getPort(ID::Y))));
} else
if (b.as_bool() == (cell->type == ID($eq))) {
RTLIL::SigSpec input = b;
ACTION_DO(ID::Y, cell->getPort(ID::A));
} else {
cover_list("opt.opt_expr.eqneq.isnot", "$eq", "$ne", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with inverter.\n", log_id(cell->type), log_id(cell), log_id(module));
cell->type = ID($not);
cell->parameters.erase(ID::B_WIDTH);
cell->parameters.erase(ID::B_SIGNED);
cell->unsetPort(ID::B);
did_something = true;
}
goto next_cell;
}
}
if (cell->type.in(ID($eq), ID($ne)) &&
(assign_map(cell->getPort(ID::A)).is_fully_zero() || assign_map(cell->getPort(ID::B)).is_fully_zero()))
{
cover_list("opt.opt_expr.eqneq.cmpzero", "$eq", "$ne", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with %s.\n", log_id(cell->type), log_id(cell),
log_id(module), cell->type == ID($eq) ? "$logic_not" : "$reduce_bool");
cell->type = cell->type == ID($eq) ? ID($logic_not) : ID($reduce_bool);
if (assign_map(cell->getPort(ID::A)).is_fully_zero()) {
cell->setPort(ID::A, cell->getPort(ID::B));
cell->setParam(ID::A_SIGNED, cell->getParam(ID::B_SIGNED));
cell->setParam(ID::A_WIDTH, cell->getParam(ID::B_WIDTH));
}
cell->unsetPort(ID::B);
cell->unsetParam(ID::B_SIGNED);
cell->unsetParam(ID::B_WIDTH);
did_something = true;
goto next_cell;
}
if (cell->type.in(ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx)) && assign_map(cell->getPort(ID::B)).is_fully_const())
{
bool sign_ext = cell->type == ID($sshr) && cell->getParam(ID::A_SIGNED).as_bool();
int shift_bits = assign_map(cell->getPort(ID::B)).as_int(cell->type.in(ID($shift), ID($shiftx)) && cell->getParam(ID::B_SIGNED).as_bool());
if (cell->type.in(ID($shl), ID($sshl)))
shift_bits *= -1;
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_y(cell->type == ID($shiftx) ? RTLIL::State::Sx : RTLIL::State::S0, cell->getParam(ID::Y_WIDTH).as_int());
if (GetSize(sig_a) < GetSize(sig_y))
sig_a.extend_u0(GetSize(sig_y), cell->getParam(ID::A_SIGNED).as_bool());
for (int i = 0; i < GetSize(sig_y); i++) {
int idx = i + shift_bits;
if (0 <= idx && idx < GetSize(sig_a))
sig_y[i] = sig_a[idx];
else if (GetSize(sig_a) <= idx && sign_ext)
sig_y[i] = sig_a[GetSize(sig_a)-1];
}
cover_list("opt.opt_expr.constshift", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", cell->type.str());
log_debug("Replacing %s cell `%s' (B=%s, SHR=%d) in module `%s' with fixed wiring: %s\n",
log_id(cell->type), log_id(cell), log_signal(assign_map(cell->getPort(ID::B))), shift_bits, log_id(module), log_signal(sig_y));
module->connect(cell->getPort(ID::Y), sig_y);
module->remove(cell);
did_something = true;
goto next_cell;
}
if (!keepdc)
{
bool identity_wrt_a = false;
bool identity_wrt_b = false;
bool arith_inverse = false;
if (cell->type.in(ID($add), ID($sub), ID($alu), ID($or), ID($xor)))
{
RTLIL::SigSpec a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
bool sub = cell->type == ID($sub);
if (cell->type == ID($alu)) {
RTLIL::SigBit sig_ci = assign_map(cell->getPort(ID::CI));
RTLIL::SigBit sig_bi = assign_map(cell->getPort(ID::BI));
sub = (sig_ci == State::S1 && sig_bi == State::S1);
// If not a subtraction, yet there is a carry or B is inverted
// then no optimisation is possible as carry will not be constant
if (!sub && (sig_ci != State::S0 || sig_bi != State::S0))
goto skip_identity;
}
if (!sub && a.is_fully_const() && a.as_bool() == false)
identity_wrt_b = true;
if (b.is_fully_const() && b.as_bool() == false)
identity_wrt_a = true;
}
if (cell->type.in(ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx)))
{
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
if (b.is_fully_const() && b.as_bool() == false)
identity_wrt_a = true;
}
if (cell->type == ID($mul))
{
RTLIL::SigSpec a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
if (a.is_fully_const() && is_one_or_minus_one(a.as_const(), cell->getParam(ID::A_SIGNED).as_bool(), arith_inverse))
identity_wrt_b = true;
else
if (b.is_fully_const() && is_one_or_minus_one(b.as_const(), cell->getParam(ID::B_SIGNED).as_bool(), arith_inverse))
identity_wrt_a = true;
}
if (cell->type == ID($div))
{
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
if (b.is_fully_const() && b.size() <= 32 && b.as_int() == 1)
identity_wrt_a = true;
}
if (identity_wrt_a || identity_wrt_b)
{
if (identity_wrt_a)
cover_list("opt.opt_expr.identwrt.a", "$add", "$sub", "$alu", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
if (identity_wrt_b)
cover_list("opt.opt_expr.identwrt.b", "$add", "$sub", "$alu", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with identity for port %c.\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), identity_wrt_a ? 'A' : 'B');
if (cell->type == ID($alu)) {
bool a_signed = cell->parameters[ID::A_SIGNED].as_bool();
bool b_signed = cell->parameters[ID::B_SIGNED].as_bool();
bool is_signed = a_signed && b_signed;
RTLIL::SigBit sig_ci = assign_map(cell->getPort(ID::CI));
int y_width = GetSize(cell->getPort(ID::Y));
if (sig_ci == State::S1) {
/* sub, b is 0 */
RTLIL::SigSpec a = cell->getPort(ID::A);
a.extend_u0(y_width, is_signed);
module->connect(cell->getPort(ID::X), module->Not(NEW_ID, a));
module->connect(cell->getPort(ID::CO), RTLIL::Const(State::S1, y_width));
} else {
/* add */
RTLIL::SigSpec ab = cell->getPort(identity_wrt_a ? ID::A : ID::B);
ab.extend_u0(y_width, is_signed);
module->connect(cell->getPort(ID::X), ab);
module->connect(cell->getPort(ID::CO), RTLIL::Const(State::S0, y_width));
}
cell->unsetPort(ID::BI);
cell->unsetPort(ID::CI);
cell->unsetPort(ID::X);
cell->unsetPort(ID::CO);
}
if (!identity_wrt_a) {
cell->setPort(ID::A, cell->getPort(ID::B));
cell->setParam(ID::A_WIDTH, cell->getParam(ID::B_WIDTH));
cell->setParam(ID::A_SIGNED, cell->getParam(ID::B_SIGNED));
}
cell->type = arith_inverse ? ID($neg) : ID($pos);
cell->unsetPort(ID::B);
cell->parameters.erase(ID::B_WIDTH);
cell->parameters.erase(ID::B_SIGNED);
cell->check();
did_something = true;
goto next_cell;
}
}
skip_identity:
if (mux_bool && cell->type.in(ID($mux), ID($_MUX_)) &&
cell->getPort(ID::A) == State::S0 && cell->getPort(ID::B) == State::S1) {
cover_list("opt.opt_expr.mux_bool", "$mux", "$_MUX_", cell->type.str());
replace_cell(assign_map, module, cell, "mux_bool", ID::Y, cell->getPort(ID::S));
goto next_cell;
}
if (mux_bool && cell->type.in(ID($mux), ID($_MUX_)) &&
cell->getPort(ID::A) == State::S1 && cell->getPort(ID::B) == State::S0) {
cover_list("opt.opt_expr.mux_invert", "$mux", "$_MUX_", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with inverter.\n", log_id(cell->type), log_id(cell), log_id(module));
cell->setPort(ID::A, cell->getPort(ID::S));
cell->unsetPort(ID::B);
cell->unsetPort(ID::S);
if (cell->type == ID($mux)) {
Const width = cell->parameters[ID::WIDTH];
cell->parameters[ID::A_WIDTH] = width;
cell->parameters[ID::Y_WIDTH] = width;
cell->parameters[ID::A_SIGNED] = 0;
cell->parameters.erase(ID::WIDTH);
cell->type = ID($not);
} else
cell->type = ID($_NOT_);
did_something = true;
goto next_cell;
}
if (consume_x && mux_bool && cell->type.in(ID($mux), ID($_MUX_)) && cell->getPort(ID::A) == State::S0) {
cover_list("opt.opt_expr.mux_and", "$mux", "$_MUX_", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with and-gate.\n", log_id(cell->type), log_id(cell), log_id(module));
cell->setPort(ID::A, cell->getPort(ID::S));
cell->unsetPort(ID::S);
if (cell->type == ID($mux)) {
Const width = cell->parameters[ID::WIDTH];
cell->parameters[ID::A_WIDTH] = width;
cell->parameters[ID::B_WIDTH] = width;
cell->parameters[ID::Y_WIDTH] = width;
cell->parameters[ID::A_SIGNED] = 0;
cell->parameters[ID::B_SIGNED] = 0;
cell->parameters.erase(ID::WIDTH);
cell->type = ID($and);
} else
cell->type = ID($_AND_);
did_something = true;
goto next_cell;
}
if (consume_x && mux_bool && cell->type.in(ID($mux), ID($_MUX_)) && cell->getPort(ID::B) == State::S1) {
cover_list("opt.opt_expr.mux_or", "$mux", "$_MUX_", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with or-gate.\n", log_id(cell->type), log_id(cell), log_id(module));
cell->setPort(ID::B, cell->getPort(ID::S));
cell->unsetPort(ID::S);
if (cell->type == ID($mux)) {
Const width = cell->parameters[ID::WIDTH];
cell->parameters[ID::A_WIDTH] = width;
cell->parameters[ID::B_WIDTH] = width;
cell->parameters[ID::Y_WIDTH] = width;
cell->parameters[ID::A_SIGNED] = 0;
cell->parameters[ID::B_SIGNED] = 0;
cell->parameters.erase(ID::WIDTH);
cell->type = ID($or);
} else
cell->type = ID($_OR_);
did_something = true;
goto next_cell;
}
if (mux_undef && cell->type.in(ID($mux), ID($pmux))) {
RTLIL::SigSpec new_a, new_b, new_s;
int width = GetSize(cell->getPort(ID::A));
if ((cell->getPort(ID::A).is_fully_undef() && cell->getPort(ID::B).is_fully_undef()) ||
cell->getPort(ID::S).is_fully_undef()) {
cover_list("opt.opt_expr.mux_undef", "$mux", "$pmux", cell->type.str());
replace_cell(assign_map, module, cell, "mux_undef", ID::Y, cell->getPort(ID::A));
goto next_cell;
}
for (int i = 0; i < cell->getPort(ID::S).size(); i++) {
RTLIL::SigSpec old_b = cell->getPort(ID::B).extract(i*width, width);
RTLIL::SigSpec old_s = cell->getPort(ID::S).extract(i, 1);
if (old_b.is_fully_undef() || old_s.is_fully_undef())
continue;
new_b.append(old_b);
new_s.append(old_s);
}
new_a = cell->getPort(ID::A);
if (new_a.is_fully_undef() && new_s.size() > 0) {
new_a = new_b.extract((new_s.size()-1)*width, width);
new_b = new_b.extract(0, (new_s.size()-1)*width);
new_s = new_s.extract(0, new_s.size()-1);
}
if (new_s.size() == 0) {
cover_list("opt.opt_expr.mux_empty", "$mux", "$pmux", cell->type.str());
replace_cell(assign_map, module, cell, "mux_empty", ID::Y, new_a);
goto next_cell;
}
if (new_a == RTLIL::SigSpec(RTLIL::State::S0) && new_b == RTLIL::SigSpec(RTLIL::State::S1)) {
cover_list("opt.opt_expr.mux_sel01", "$mux", "$pmux", cell->type.str());
replace_cell(assign_map, module, cell, "mux_sel01", ID::Y, new_s);
goto next_cell;
}
if (cell->getPort(ID::S).size() != new_s.size()) {
cover_list("opt.opt_expr.mux_reduce", "$mux", "$pmux", cell->type.str());
log_debug("Optimized away %d select inputs of %s cell `%s' in module `%s'.\n",
GetSize(cell->getPort(ID::S)) - GetSize(new_s), log_id(cell->type), log_id(cell), log_id(module));
cell->setPort(ID::A, new_a);
cell->setPort(ID::B, new_b);
cell->setPort(ID::S, new_s);
if (new_s.size() > 1) {
cell->type = ID($pmux);
cell->parameters[ID::S_WIDTH] = new_s.size();
} else {
cell->type = ID($mux);
cell->parameters.erase(ID::S_WIDTH);
}
did_something = true;
}
}
#define FOLD_1ARG_CELL(_t) \
if (cell->type == ID($##_t)) { \
RTLIL::SigSpec a = cell->getPort(ID::A); \
assign_map.apply(a); \
if (a.is_fully_const()) { \
RTLIL::Const dummy_arg(RTLIL::State::S0, 1); \
RTLIL::SigSpec y(RTLIL::const_ ## _t(a.as_const(), dummy_arg, \
cell->parameters[ID::A_SIGNED].as_bool(), false, \
cell->parameters[ID::Y_WIDTH].as_int())); \
cover("opt.opt_expr.const.$" #_t); \
replace_cell(assign_map, module, cell, stringf("%s", log_signal(a)), ID::Y, y); \
goto next_cell; \
} \
}
#define FOLD_2ARG_CELL(_t) \
if (cell->type == ID($##_t)) { \
RTLIL::SigSpec a = cell->getPort(ID::A); \
RTLIL::SigSpec b = cell->getPort(ID::B); \
assign_map.apply(a), assign_map.apply(b); \
if (a.is_fully_const() && b.is_fully_const()) { \
RTLIL::SigSpec y(RTLIL::const_ ## _t(a.as_const(), b.as_const(), \
cell->parameters[ID::A_SIGNED].as_bool(), \
cell->parameters[ID::B_SIGNED].as_bool(), \
cell->parameters[ID::Y_WIDTH].as_int())); \
cover("opt.opt_expr.const.$" #_t); \
replace_cell(assign_map, module, cell, stringf("%s, %s", log_signal(a), log_signal(b)), ID::Y, y); \
goto next_cell; \
} \
}
FOLD_1ARG_CELL(not)
FOLD_2ARG_CELL(and)
FOLD_2ARG_CELL(or)
FOLD_2ARG_CELL(xor)
FOLD_2ARG_CELL(xnor)
FOLD_1ARG_CELL(reduce_and)
FOLD_1ARG_CELL(reduce_or)
FOLD_1ARG_CELL(reduce_xor)
FOLD_1ARG_CELL(reduce_xnor)
FOLD_1ARG_CELL(reduce_bool)
FOLD_1ARG_CELL(logic_not)
FOLD_2ARG_CELL(logic_and)
FOLD_2ARG_CELL(logic_or)
FOLD_2ARG_CELL(shl)
FOLD_2ARG_CELL(shr)
FOLD_2ARG_CELL(sshl)
FOLD_2ARG_CELL(sshr)
FOLD_2ARG_CELL(shift)
FOLD_2ARG_CELL(shiftx)
FOLD_2ARG_CELL(lt)
FOLD_2ARG_CELL(le)
FOLD_2ARG_CELL(eq)
FOLD_2ARG_CELL(ne)
FOLD_2ARG_CELL(gt)
FOLD_2ARG_CELL(ge)
FOLD_2ARG_CELL(add)
FOLD_2ARG_CELL(sub)
FOLD_2ARG_CELL(mul)
FOLD_2ARG_CELL(div)
FOLD_2ARG_CELL(mod)
FOLD_2ARG_CELL(pow)
FOLD_1ARG_CELL(pos)
FOLD_1ARG_CELL(neg)
// be very conservative with optimizing $mux cells as we do not want to break mux trees
if (cell->type == ID($mux)) {
RTLIL::SigSpec input = assign_map(cell->getPort(ID::S));
RTLIL::SigSpec inA = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec inB = assign_map(cell->getPort(ID::B));
if (input.is_fully_const())
ACTION_DO(ID::Y, input.as_bool() ? cell->getPort(ID::B) : cell->getPort(ID::A));
else if (inA == inB)
ACTION_DO(ID::Y, cell->getPort(ID::A));
}
if (!keepdc && cell->type == ID($mul))
{
bool a_signed = cell->parameters[ID::A_SIGNED].as_bool();
bool b_signed = cell->parameters[ID::B_SIGNED].as_bool();
bool swapped_ab = false;
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::SigSpec sig_y = assign_map(cell->getPort(ID::Y));
if (sig_b.is_fully_const() && sig_b.size() <= 32)
std::swap(sig_a, sig_b), std::swap(a_signed, b_signed), swapped_ab = true;
if (sig_a.is_fully_def() && sig_a.size() <= 32)
{
int a_val = sig_a.as_int();
if (a_val == 0)
{
cover("opt.opt_expr.mul_shift.zero");
log_debug("Replacing multiply-by-zero cell `%s' in module `%s' with zero-driver.\n",
cell->name.c_str(), module->name.c_str());
module->connect(RTLIL::SigSig(sig_y, RTLIL::SigSpec(0, sig_y.size())));
module->remove(cell);
did_something = true;
goto next_cell;
}
for (int i = 1; i < (a_signed ? sig_a.size()-1 : sig_a.size()); i++)
if (a_val == (1 << i))
{
if (swapped_ab)
cover("opt.opt_expr.mul_shift.swapped");
else
cover("opt.opt_expr.mul_shift.unswapped");
log_debug("Replacing multiply-by-%d cell `%s' in module `%s' with shift-by-%d.\n",
a_val, cell->name.c_str(), module->name.c_str(), i);
if (!swapped_ab) {
cell->setPort(ID::A, cell->getPort(ID::B));
cell->parameters.at(ID::A_WIDTH) = cell->parameters.at(ID::B_WIDTH);
cell->parameters.at(ID::A_SIGNED) = cell->parameters.at(ID::B_SIGNED);
}
std::vector<RTLIL::SigBit> new_b = RTLIL::SigSpec(i, 6);
while (GetSize(new_b) > 1 && new_b.back() == RTLIL::State::S0)
new_b.pop_back();
cell->type = ID($shl);
cell->parameters[ID::B_WIDTH] = GetSize(new_b);
cell->parameters[ID::B_SIGNED] = false;
cell->setPort(ID::B, new_b);
cell->check();
did_something = true;
goto next_cell;
}
}
sig_a = assign_map(cell->getPort(ID::A));
sig_b = assign_map(cell->getPort(ID::B));
int a_zeros, b_zeros;
for (a_zeros = 0; a_zeros < GetSize(sig_a); a_zeros++)
if (sig_a[a_zeros] != RTLIL::State::S0)
break;
for (b_zeros = 0; b_zeros < GetSize(sig_b); b_zeros++)
if (sig_b[b_zeros] != RTLIL::State::S0)
break;
if (a_zeros || b_zeros) {
int y_zeros = a_zeros + b_zeros;
cover("opt.opt_expr.mul_low_zeros");
log_debug("Removing low %d A and %d B bits from cell `%s' in module `%s'.\n",
a_zeros, b_zeros, cell->name.c_str(), module->name.c_str());
if (a_zeros) {
cell->setPort(ID::A, sig_a.extract_end(a_zeros));
cell->parameters[ID::A_WIDTH] = GetSize(sig_a) - a_zeros;
}
if (b_zeros) {
cell->setPort(ID::B, sig_b.extract_end(b_zeros));
cell->parameters[ID::B_WIDTH] = GetSize(sig_b) - b_zeros;
}
cell->setPort(ID::Y, sig_y.extract_end(y_zeros));
cell->parameters[ID::Y_WIDTH] = GetSize(sig_y) - y_zeros;
module->connect(RTLIL::SigSig(sig_y.extract(0, y_zeros), RTLIL::SigSpec(0, y_zeros)));
cell->check();
did_something = true;
goto next_cell;
}
}
if (!keepdc && cell->type.in(ID($div), ID($mod)))
{
bool b_signed = cell->parameters[ID::B_SIGNED].as_bool();
SigSpec sig_b = assign_map(cell->getPort(ID::B));
SigSpec sig_y = assign_map(cell->getPort(ID::Y));
if (sig_b.is_fully_def() && sig_b.size() <= 32)
{
int b_val = sig_b.as_int();
if (b_val == 0)
{
cover("opt.opt_expr.divmod_zero");
log_debug("Replacing divide-by-zero cell `%s' in module `%s' with undef-driver.\n",
cell->name.c_str(), module->name.c_str());
module->connect(RTLIL::SigSig(sig_y, RTLIL::SigSpec(State::Sx, sig_y.size())));
module->remove(cell);
did_something = true;
goto next_cell;
}
for (int i = 1; i < (b_signed ? sig_b.size()-1 : sig_b.size()); i++)
if (b_val == (1 << i))
{
if (cell->type == ID($div))
{
cover("opt.opt_expr.div_shift");
log_debug("Replacing divide-by-%d cell `%s' in module `%s' with shift-by-%d.\n",
b_val, cell->name.c_str(), module->name.c_str(), i);
std::vector<RTLIL::SigBit> new_b = RTLIL::SigSpec(i, 6);
while (GetSize(new_b) > 1 && new_b.back() == RTLIL::State::S0)
new_b.pop_back();
cell->type = ID($shr);
cell->parameters[ID::B_WIDTH] = GetSize(new_b);
cell->parameters[ID::B_SIGNED] = false;
cell->setPort(ID::B, new_b);
cell->check();
}
else
{
cover("opt.opt_expr.mod_mask");
log_debug("Replacing modulo-by-%d cell `%s' in module `%s' with bitmask.\n",
b_val, cell->name.c_str(), module->name.c_str());
std::vector<RTLIL::SigBit> new_b = RTLIL::SigSpec(State::S1, i);
if (b_signed)
new_b.push_back(State::S0);
cell->type = ID($and);
cell->parameters[ID::B_WIDTH] = GetSize(new_b);
cell->setPort(ID::B, new_b);
cell->check();
}
did_something = true;
goto next_cell;
}
}
}
// Find places in $alu cell where the carry is constant, and split it at these points.
if (do_fine && !keepdc && cell->type == ID($alu))
{
bool a_signed = cell->parameters[ID::A_SIGNED].as_bool();
bool b_signed = cell->parameters[ID::B_SIGNED].as_bool();
bool is_signed = a_signed && b_signed;
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
RTLIL::SigSpec sig_y = assign_map(cell->getPort(ID::Y));
RTLIL::SigSpec sig_bi = assign_map(cell->getPort(ID::BI));
if (GetSize(sig_a) == 0)
sig_a = State::S0;
if (GetSize(sig_b) == 0)
sig_b = State::S0;
sig_a.extend_u0(GetSize(sig_y), is_signed);
sig_b.extend_u0(GetSize(sig_y), is_signed);
if (sig_bi != State::S0 && sig_bi != State::S1)
goto skip_alu_split;
std::vector<std::pair<int, State>> split_points;
for (int i = 0; i < GetSize(sig_y); i++) {
SigBit bit_a = sig_a[i];
SigBit bit_b = sig_b[i];
if (bit_a != State::S0 && bit_a != State::S1)
continue;
if (bit_b != State::S0 && bit_b != State::S1)
continue;
if (sig_bi == State::S1) {
if (bit_b == State::S0)
bit_b = State::S1;
else
bit_b = State::S0;
}
if (bit_a != bit_b)
continue;
split_points.push_back(std::make_pair(i + 1, bit_a.data));
}
if (split_points.empty() || split_points[0].first == GetSize(sig_y))
goto skip_alu_split;
for (auto &p : split_points)
log_debug("Splitting $alu cell `%s' in module `%s' at const-carry point %d.\n",
cell->name.c_str(), module->name.c_str(), p.first);
if (split_points.back().first != GetSize(sig_y))
split_points.push_back(std::make_pair(GetSize(sig_y), State::Sx));
RTLIL::SigSpec sig_ci = assign_map(cell->getPort(ID::CI));
int prev = 0;
RTLIL::SigSpec sig_x = assign_map(cell->getPort(ID::X));
RTLIL::SigSpec sig_co = assign_map(cell->getPort(ID::CO));
for (auto &p : split_points) {
int cur = p.first;
int sz = cur - prev;
bool last = cur == GetSize(sig_y);
RTLIL::Cell *c = module->addCell(NEW_ID, cell->type);
c->setPort(ID::A, sig_a.extract(prev, sz));
c->setPort(ID::B, sig_b.extract(prev, sz));
c->setPort(ID::BI, sig_bi);
c->setPort(ID::CI, sig_ci);
c->setPort(ID::Y, sig_y.extract(prev, sz));
c->setPort(ID::X, sig_x.extract(prev, sz));
RTLIL::SigSpec new_co = sig_co.extract(prev, sz);
if (p.second != State::Sx) {
module->connect(new_co[sz-1], p.second);
RTLIL::Wire *dummy = module->addWire(NEW_ID);
new_co[sz-1] = dummy;
}
c->setPort(ID::CO, new_co);
c->parameters[ID::A_WIDTH] = sz;
c->parameters[ID::B_WIDTH] = sz;
c->parameters[ID::Y_WIDTH] = sz;
c->parameters[ID::A_SIGNED] = last ? a_signed : false;
c->parameters[ID::B_SIGNED] = last ? b_signed : false;
prev = p.first;
sig_ci = p.second;
}
cover("opt.opt_expr.alu_split");
module->remove(cell);
did_something = true;
goto next_cell;
}
skip_alu_split:
// remove redundant pairs of bits in ==, ===, !=, and !==
// replace cell with const driver if inputs can't be equal
if (do_fine && cell->type.in(ID($eq), ID($ne), ID($eqx), ID($nex)))
{
pool<pair<SigBit, SigBit>> redundant_cache;
mfp<SigBit> contradiction_cache;
contradiction_cache.promote(State::S0);
contradiction_cache.promote(State::S1);
int a_width = cell->getParam(ID::A_WIDTH).as_int();
int b_width = cell->getParam(ID::B_WIDTH).as_int();
bool is_signed = cell->getParam(ID::A_SIGNED).as_bool();
int width = is_signed ? std::min(a_width, b_width) : std::max(a_width, b_width);
SigSpec sig_a = cell->getPort(ID::A);
SigSpec sig_b = cell->getPort(ID::B);
int redundant_bits = 0;
for (int i = width-1; i >= 0; i--)
{
SigBit bit_a = i < a_width ? assign_map(sig_a[i]) : State::S0;
SigBit bit_b = i < b_width ? assign_map(sig_b[i]) : State::S0;
if (bit_a != State::Sx && bit_a != State::Sz &&
bit_b != State::Sx && bit_b != State::Sz)
contradiction_cache.merge(bit_a, bit_b);
if (bit_b < bit_a)
std::swap(bit_a, bit_b);
pair<SigBit, SigBit> key(bit_a, bit_b);
if (redundant_cache.count(key)) {
if (i < a_width) sig_a.remove(i);
if (i < b_width) sig_b.remove(i);
redundant_bits++;
continue;
}
redundant_cache.insert(key);
}
if (contradiction_cache.find(State::S0) == contradiction_cache.find(State::S1))
{
SigSpec y_sig = cell->getPort(ID::Y);
Const y_value(cell->type.in(ID($eq), ID($eqx)) ? 0 : 1, GetSize(y_sig));
log_debug("Replacing cell `%s' in module `%s' with constant driver %s.\n",
log_id(cell), log_id(module), log_signal(y_value));
module->connect(y_sig, y_value);
module->remove(cell);
did_something = true;
goto next_cell;
}
if (redundant_bits)
{
log_debug("Removed %d redundant input bits from %s cell `%s' in module `%s'.\n",
redundant_bits, log_id(cell->type), log_id(cell), log_id(module));
cell->setPort(ID::A, sig_a);
cell->setPort(ID::B, sig_b);
cell->setParam(ID::A_WIDTH, GetSize(sig_a));
cell->setParam(ID::B_WIDTH, GetSize(sig_b));
did_something = true;
goto next_cell;
}
}
// simplify comparisons
if (do_fine && cell->type.in(ID($lt), ID($ge), ID($gt), ID($le)))
{
IdString cmp_type = cell->type;
SigSpec var_sig = cell->getPort(ID::A);
SigSpec const_sig = cell->getPort(ID::B);
int var_width = cell->parameters[ID::A_WIDTH].as_int();
int const_width = cell->parameters[ID::B_WIDTH].as_int();
bool is_signed = cell->getParam(ID::A_SIGNED).as_bool();
if (!const_sig.is_fully_const())
{
std::swap(var_sig, const_sig);
std::swap(var_width, const_width);
if (cmp_type == ID($gt))
cmp_type = ID($lt);
else if (cmp_type == ID($lt))
cmp_type = ID($gt);
else if (cmp_type == ID($ge))
cmp_type = ID($le);
else if (cmp_type == ID($le))
cmp_type = ID($ge);
}
if (const_sig.is_fully_def() && const_sig.is_fully_const())
{
std::string condition, replacement;
SigSpec replace_sig(State::S0, GetSize(cell->getPort(ID::Y)));
bool replace = false;
bool remove = false;
if (!is_signed)
{ /* unsigned */
if (const_sig.is_fully_zero() && cmp_type == ID($lt)) {
condition = "unsigned X<0";
replacement = "constant 0";
replace_sig[0] = State::S0;
replace = true;
}
if (const_sig.is_fully_zero() && cmp_type == ID($ge)) {
condition = "unsigned X>=0";
replacement = "constant 1";
replace_sig[0] = State::S1;
replace = true;
}
if (const_width == var_width && const_sig.is_fully_ones() && cmp_type == ID($gt)) {
condition = "unsigned X>~0";
replacement = "constant 0";
replace_sig[0] = State::S0;
replace = true;
}
if (const_width == var_width && const_sig.is_fully_ones() && cmp_type == ID($le)) {
condition = "unsigned X<=~0";
replacement = "constant 1";
replace_sig[0] = State::S1;
replace = true;
}
int const_bit_hot = get_onehot_bit_index(const_sig);
if (const_bit_hot >= 0 && const_bit_hot < var_width)
{
RTLIL::SigSpec var_high_sig(RTLIL::State::S0, var_width - const_bit_hot);
for (int i = const_bit_hot; i < var_width; i++) {
var_high_sig[i - const_bit_hot] = var_sig[i];
}
if (cmp_type == ID($lt))
{
condition = stringf("unsigned X<%s", log_signal(const_sig));
replacement = stringf("!X[%d:%d]", var_width - 1, const_bit_hot);
module->addLogicNot(NEW_ID, var_high_sig, cell->getPort(ID::Y));
remove = true;
}
if (cmp_type == ID($ge))
{
condition = stringf("unsigned X>=%s", log_signal(const_sig));
replacement = stringf("|X[%d:%d]", var_width - 1, const_bit_hot);
module->addReduceOr(NEW_ID, var_high_sig, cell->getPort(ID::Y));
remove = true;
}
}
int const_bit_set = get_highest_hot_index(const_sig);
if (const_bit_set >= var_width)
{
string cmp_name;
if (cmp_type == ID($lt) || cmp_type == ID($le))
{
if (cmp_type == ID($lt)) cmp_name = "<";
if (cmp_type == ID($le)) cmp_name = "<=";
condition = stringf("unsigned X[%d:0]%s%s", var_width - 1, cmp_name.c_str(), log_signal(const_sig));
replacement = "constant 1";
replace_sig[0] = State::S1;
replace = true;
}
if (cmp_type == ID($gt) || cmp_type == ID($ge))
{
if (cmp_type == ID($gt)) cmp_name = ">";
if (cmp_type == ID($ge)) cmp_name = ">=";
condition = stringf("unsigned X[%d:0]%s%s", var_width - 1, cmp_name.c_str(), log_signal(const_sig));
replacement = "constant 0";
replace_sig[0] = State::S0;
replace = true;
}
}
}
else
{ /* signed */
if (const_sig.is_fully_zero() && cmp_type == ID($lt))
{
condition = "signed X<0";
replacement = stringf("X[%d]", var_width - 1);
replace_sig[0] = var_sig[var_width - 1];
replace = true;
}
if (const_sig.is_fully_zero() && cmp_type == ID($ge))
{
condition = "signed X>=0";
replacement = stringf("X[%d]", var_width - 1);
module->addNot(NEW_ID, var_sig[var_width - 1], cell->getPort(ID::Y));
remove = true;
}
}
if (replace || remove)
{
log_debug("Replacing %s cell `%s' (implementing %s) with %s.\n",
log_id(cell->type), log_id(cell), condition.c_str(), replacement.c_str());
if (replace)
module->connect(cell->getPort(ID::Y), replace_sig);
module->remove(cell);
did_something = true;
goto next_cell;
}
}
}
next_cell:;
#undef ACTION_DO
#undef ACTION_DO_Y
#undef FOLD_1ARG_CELL
#undef FOLD_2ARG_CELL
}
}
struct OptExprPass : public Pass {
OptExprPass() : Pass("opt_expr", "perform const folding and simple expression rewriting") { }
void help() YS_OVERRIDE
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" opt_expr [options] [selection]\n");
log("\n");
log("This pass performs const folding on internal cell types with constant inputs.\n");
log("It also performs some simple expression rewriting.\n");
log("\n");
log(" -mux_undef\n");
log(" remove 'undef' inputs from $mux, $pmux and $_MUX_ cells\n");
log("\n");
log(" -mux_bool\n");
log(" replace $mux cells with inverters or buffers when possible\n");
log("\n");
log(" -undriven\n");
log(" replace undriven nets with undef (x) constants\n");
log("\n");
log(" -clkinv\n");
log(" optimize clock inverters by changing FF types\n");
log("\n");
log(" -fine\n");
log(" perform fine-grain optimizations\n");
log("\n");
log(" -full\n");
log(" alias for -mux_undef -mux_bool -undriven -fine\n");
log("\n");
log(" -keepdc\n");
log(" some optimizations change the behavior of the circuit with respect to\n");
log(" don't-care bits. for example in 'a+0' a single x-bit in 'a' will cause\n");
log(" all result bits to be set to x. this behavior changes when 'a+0' is\n");
log(" replaced by 'a'. the -keepdc option disables all such optimizations.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
{
bool mux_undef = false;
bool mux_bool = false;
bool undriven = false;
bool clkinv = false;
bool do_fine = false;
bool keepdc = false;
log_header(design, "Executing OPT_EXPR pass (perform const folding).\n");
log_push();
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-mux_undef") {
mux_undef = true;
continue;
}
if (args[argidx] == "-mux_bool") {
mux_bool = true;
continue;
}
if (args[argidx] == "-undriven") {
undriven = true;
continue;
}
if (args[argidx] == "-clkinv") {
clkinv = true;
continue;
}
if (args[argidx] == "-fine") {
do_fine = true;
continue;
}
if (args[argidx] == "-full") {
mux_undef = true;
mux_bool = true;
undriven = true;
do_fine = true;
continue;
}
if (args[argidx] == "-keepdc") {
keepdc = true;
continue;
}
break;
}
extra_args(args, argidx, design);
CellTypes ct(design);
for (auto module : design->selected_modules())
{
log("Optimizing module %s.\n", log_id(module));
if (undriven) {
did_something = false;
replace_undriven(module, ct);
if (did_something)
design->scratchpad_set_bool("opt.did_something", true);
}
do {
do {
did_something = false;
replace_const_cells(design, module, false, mux_undef, mux_bool, do_fine, keepdc, clkinv);
if (did_something)
design->scratchpad_set_bool("opt.did_something", true);
} while (did_something);
replace_const_cells(design, module, true, mux_undef, mux_bool, do_fine, keepdc, clkinv);
if (did_something)
design->scratchpad_set_bool("opt.did_something", true);
} while (did_something);
log_suppressed();
}
log_pop();
}
} OptExprPass;
PRIVATE_NAMESPACE_END
Reference in New Issue View Git Blame Copy Permalink