This commit is contained in:
George Rennie 2024-11-25 15:44:59 +01:00 committed by GitHub
commit fc52ccb02b
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
18 changed files with 333 additions and 32 deletions

View File

@ -28,8 +28,8 @@
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
#define BITWISE_OPS ID($buf), ID($not), ID($mux), ID($and), ID($or), ID($xor), ID($xnor), ID($fa), \
ID($bwmux)
#define BITWISE_OPS ID($buf), ID($barrier), ID($not), ID($mux), ID($and), ID($or), ID($xor), ID($xnor), \
ID($fa), ID($bwmux)
#define REDUCE_OPS ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_xnor), ID($reduce_bool)
@ -331,7 +331,7 @@ struct Index {
a = CFALSE;
}
if (cell->type.in(ID($buf), ID($pos), ID($_BUF_))) {
if (cell->type.in(ID($buf), ID($barrier), ID($pos), ID($_BUF_))) {
return a;
} else if (cell->type.in(ID($not), ID($_NOT_))) {
return NOT(a);

View File

@ -508,7 +508,7 @@ struct BtorWorker
goto okay;
}
if (cell->type.in(ID($not), ID($neg), ID($_NOT_), ID($pos)))
if (cell->type.in(ID($not), ID($neg), ID($_NOT_), ID($pos), ID($buf), ID($_BUF_), ID($barrier)))
{
string btor_op;
if (cell->type.in(ID($not), ID($_NOT_))) btor_op = "not";
@ -520,9 +520,9 @@ struct BtorWorker
int nid_a = get_sig_nid(cell->getPort(ID::A), width, a_signed);
SigSpec sig = sigmap(cell->getPort(ID::Y));
// the $pos cell just passes through, all other cells need an actual operation applied
// buffer cells just pass through, all other cells need an actual operation applied
int nid = nid_a;
if (cell->type != ID($pos))
if (!cell->type.in(ID($pos), ID($buf), ID($_BUF_), ID($barrier)))
{
log_assert(!btor_op.empty());
int sid = get_bv_sid(width);

View File

@ -966,7 +966,7 @@ struct FirrtlWorker
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
}
if (cell->type == ID($pos)) {
if (cell->type.in(ID($pos), ID($buf), ID($barrier))) {
// assign y = a;
// printCell(cell);
string a_expr = make_expr(cell->getPort(ID::A));

View File

@ -677,7 +677,7 @@ struct Smt2Worker
if (cell->type == ID($eqx)) return export_bvop(cell, "(= A B)", 'b');
if (cell->type == ID($not)) return export_bvop(cell, "(bvnot A)");
if (cell->type == ID($pos)) return export_bvop(cell, "A");
if (cell->type.in(ID($pos), ID($buf), ID($barrier))) return export_bvop(cell, "A");
if (cell->type == ID($neg)) return export_bvop(cell, "(bvneg A)");
if (cell->type == ID($add)) return export_bvop(cell, "(bvadd A B)");

View File

@ -1071,7 +1071,7 @@ bool dump_cell_expr(std::ostream &f, std::string indent, RTLIL::Cell *cell)
return true;
}
if (cell->type == ID($_BUF_)) {
if (cell->type.in(ID($buf), ID($_BUF_), ID($barrier))) {
f << stringf("%s" "assign ", indent.c_str());
dump_sigspec(f, cell->getPort(ID::Y));
f << stringf(" = ");

View File

@ -290,7 +290,7 @@ Aig::Aig(Cell *cell)
}
}
if (cell->type.in(ID($not), ID($_NOT_), ID($pos), ID($buf), ID($_BUF_)))
if (cell->type.in(ID($not), ID($_NOT_), ID($pos), ID($buf), ID($barrier), ID($_BUF_)))
{
for (int i = 0; i < GetSize(cell->getPort(ID::Y)); i++) {
int A = mk.inport(ID::A, i);

View File

@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
void bitwise_unary_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
{
bool is_signed = (cell->type != ID($buf)) && cell->getParam(ID::A_SIGNED).as_bool();
bool is_signed = !cell->type.in(ID($buf), ID($barrier)) && cell->getParam(ID::A_SIGNED).as_bool();
int a_width = GetSize(cell->getPort(ID::A));
int y_width = GetSize(cell->getPort(ID::Y));
@ -392,7 +392,7 @@ PRIVATE_NAMESPACE_END
bool YOSYS_NAMESPACE_PREFIX AbstractCellEdgesDatabase::add_edges_from_cell(RTLIL::Cell *cell)
{
if (cell->type.in(ID($not), ID($pos), ID($buf))) {
if (cell->type.in(ID($not), ID($pos), ID($buf), ID($barrier))) {
bitwise_unary_op(this, cell);
return true;
}

View File

@ -87,6 +87,8 @@ struct CellTypes
{
setup_internals_eval();
setup_type(ID($barrier), {ID::A}, {ID::Y});
setup_type(ID($tribuf), {ID::A, ID::EN}, {ID::Y}, true);
setup_type(ID($assert), {ID::A, ID::EN}, pool<RTLIL::IdString>(), true);

View File

@ -77,7 +77,7 @@ void QuickConeSat::prepare()
int QuickConeSat::cell_complexity(RTLIL::Cell *cell)
{
if (cell->type.in(ID($concat), ID($slice), ID($pos), ID($buf), ID($_BUF_)))
if (cell->type.in(ID($concat), ID($slice), ID($pos), ID($buf), ID($barrier), ID($_BUF_)))
return 0;
if (cell->type.in(ID($not), ID($and), ID($or), ID($xor), ID($xnor),
ID($reduce_and), ID($reduce_or), ID($reduce_xor),

View File

@ -1340,7 +1340,7 @@ namespace {
cell->type.begins_with("$verific$") || cell->type.begins_with("$array:") || cell->type.begins_with("$extern:"))
return;
if (cell->type == ID($buf)) {
if (cell->type.in(ID($buf), ID($barrier))) {
port(ID::A, param(ID::WIDTH));
port(ID::Y, param(ID::WIDTH));
check_expected();
@ -2746,7 +2746,8 @@ DEF_METHOD(LogicNot, 1, ID($logic_not))
add ## _func(name, sig_a, sig_y, is_signed, src); \
return sig_y; \
}
DEF_METHOD(Buf, sig_a.size(), ID($buf))
DEF_METHOD(Buf, sig_a.size(), ID($buf))
DEF_METHOD(Barrier, sig_a.size(), ID($barrier))
#undef DEF_METHOD
#define DEF_METHOD(_func, _y_size, _type) \
@ -4048,9 +4049,9 @@ void RTLIL::Cell::fixup_parameters(bool set_a_signed, bool set_b_signed)
type.begins_with("$verific$") || type.begins_with("$array:") || type.begins_with("$extern:"))
return;
if (type == ID($buf) || type == ID($mux) || type == ID($pmux) || type == ID($bmux)) {
if (type.in(ID($buf), ID($barrier), ID($mux), ID($pmux), ID($bmux))) {
parameters[ID::WIDTH] = GetSize(connections_[ID::Y]);
if (type != ID($buf) && type != ID($mux))
if (!type.in(ID($buf), ID($barrier), ID($mux)))
parameters[ID::S_WIDTH] = GetSize(connections_[ID::S]);
check();
return;

View File

@ -1371,10 +1371,11 @@ public:
// The add* methods create a cell and return the created cell. All signals must exist in advance.
RTLIL::Cell* addNot (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addPos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addBuf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addNeg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addNot (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addPos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addBuf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addBarrier (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addNeg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addAnd (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addOr (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
@ -1506,10 +1507,11 @@ public:
// The methods without the add* prefix create a cell and an output signal. They return the newly created output signal.
RTLIL::SigSpec Not (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Pos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Buf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Neg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Not (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Pos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Buf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Barrier (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Neg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec And (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Or (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");

View File

@ -430,7 +430,7 @@ bool SatGen::importCell(RTLIL::Cell *cell, int timestep)
return true;
}
if (cell->type.in(ID($pos), ID($buf), ID($neg)))
if (cell->type.in(ID($pos), ID($buf), ID($barrier), ID($neg)))
{
std::vector<int> a = importDefSigSpec(cell->getPort(ID::A), timestep);
std::vector<int> y = importDefSigSpec(cell->getPort(ID::Y), timestep);
@ -438,7 +438,7 @@ bool SatGen::importCell(RTLIL::Cell *cell, int timestep)
std::vector<int> yy = model_undef ? ez->vec_var(y.size()) : y;
if (cell->type.in(ID($pos), ID($buf))) {
if (cell->type.in(ID($pos), ID($buf), ID($barrier))) {
ez->assume(ez->vec_eq(a, yy));
} else {
std::vector<int> zero(a.size(), ez->CONST_FALSE);
@ -451,7 +451,7 @@ bool SatGen::importCell(RTLIL::Cell *cell, int timestep)
std::vector<int> undef_y = importUndefSigSpec(cell->getPort(ID::Y), timestep);
extendSignalWidthUnary(undef_a, undef_y, cell);
if (cell->type.in(ID($pos), ID($buf))) {
if (cell->type.in(ID($pos), ID($buf), ID($barrier))) {
ez->assume(ez->vec_eq(undef_a, undef_y));
} else {
int undef_any_a = ez->expression(ezSAT::OpOr, undef_a);

View File

@ -51,3 +51,4 @@ OBJS += passes/cmds/future.o
OBJS += passes/cmds/box_derive.o
OBJS += passes/cmds/example_dt.o
OBJS += passes/cmds/portarcs.o
OBJS += passes/cmds/optbarriers.o

228
passes/cmds/optbarriers.cc Normal file
View File

@ -0,0 +1,228 @@
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2024 George Rennie <georgrennie@gmail.com>
*
* 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/yosys.h"
#include "kernel/sigtools.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
// Standard visitor helper
template<class... Ts>
struct overloaded : Ts... { using Ts::operator()...; };
template<class... Ts>
overloaded(Ts...) -> overloaded<Ts...>;
struct OptBarriersPass : public Pass {
OptBarriersPass() : Pass("optbarriers", "insert optimization barriers") {}
void help() override {
log("\n");
log(" optbarriers [options] [selection]\n");
log("\n");
log("Insert optimization barriers to drivers of selected public wires.\n");
log("\n");
log("\n");
log(" -nocells\n");
log(" don't add optimization barriers to the outputs of cells\n");
log("\n");
log(" -noprocs\n");
log(" don't add optimization barriers to the outputs of processes\n");
log("\n");
log(" -private\n");
log(" also add optimization barriers to private wires\n");
log("\n");
log(" -remove\n");
log(" replace selected optimization barriers with connections\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override {
log_header(design, "Executing OPTBARRIERS pass (insert optimization barriers).\n");
bool nocells_mode = false;
bool noprocs_mode = false;
bool private_mode = false;
bool remove_mode = false;
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
std::string arg = args[argidx];
if (arg == "-nocells") {
nocells_mode = true;
continue;
}
if (arg == "-noprocs") {
noprocs_mode = true;
continue;
}
if (arg == "-private") {
private_mode = true;
continue;
}
if (arg == "-remove") {
remove_mode = true;
continue;
}
break;
}
extra_args(args, argidx, design);
if (remove_mode) {
log("Replacing optimization barriers with connections.\n");
remove_barriers(design);
return;
}
for (auto* module : design->selected_modules()) {
// We can't just sigmap and iterate through wires for rewriting as
// we want to maintain the structure in connections, and sigmap
// will just return a canonical wire which does not have to be one
// that is directly driving the wire. Therefore for each type of
// object that could be driving the wires (cells, processes,
// connections) we rewrite the sigspecs.
// Keep track of which wires we have allocated new wires for
dict<RTLIL::Wire*, RTLIL::Wire*> new_wires;
// Keep track of bit pairs we need to construct barriers for from
// Y to A
dict<RTLIL::SigBit, RTLIL::SigBit> new_barriers;
// Skip constants, unselected wires and private wires when not in
// private mode. This works for SigChunk or SigBit input.
const auto skip = [&](const auto& chunk) {
if (!chunk.is_wire())
return true;
if (!design->selected(module, chunk.wire))
return true;
if (!private_mode && !chunk.wire->name.isPublic())
return true;
return false;
};
const auto rewrite_sigspec = [&](const SigSpec& sig) {
RTLIL::SigSpec new_output;
for (const auto& chunk : sig.chunks()) {
if (skip(chunk)) {
new_output.append(chunk);
continue;
}
// Add a wire to drive if one does not already exist
auto* new_wire = new_wires.at(chunk.wire, nullptr);
if (!new_wire) {
new_wire = module->addWire(NEW_ID, GetSize(chunk.wire));
new_wires.emplace(chunk.wire, new_wire);
}
RTLIL::SigChunk new_chunk = chunk;
new_chunk.wire = new_wire;
// Rewrite output to drive new wire, and schedule adding
// barrier bits from new wire to original
new_output.append(new_chunk);
for (int i = 0; i < GetSize(chunk); i++)
new_barriers.emplace(chunk[i], new_chunk[i]);
}
return new_output;
};
// Rewrite cell outputs
if (!nocells_mode)
for (auto* cell : module->cells())
if (cell->type != ID($barrier))
for (const auto& [name, sig] : cell->connections())
if (cell->output(name))
cell->setPort(name, rewrite_sigspec(sig));
// Rewrite connections in processes
if (!noprocs_mode) {
const auto proc_rewriter = overloaded{
// Don't do anything for input sigspecs
[&](const SigSpec&) {},
// Rewrite connections to drive barrier if needed
[&](SigSpec& lhs, const SigSpec&) {
lhs = rewrite_sigspec(lhs);
}
};
for (auto& proc : module->processes)
proc.second->rewrite_sigspecs2(proc_rewriter);
}
// Add all the scheduled barriers. To minimize the number of cells,
// first construct a sigspec of all bits, then sort and unify before
// creating barriers
SigSpec barrier_y;
for (const auto&[y_bit, _] : new_barriers)
barrier_y.append(y_bit);
barrier_y.sort_and_unify();
for (const auto& sig_y : barrier_y.chunks()) {
log_assert(sig_y.is_wire());
SigSpec sig_a;
for (int i = 0; i < GetSize(sig_y); i++)
sig_a.append(new_barriers[sig_y[i]]);
module->addBarrier(NEW_ID, sig_a, sig_y);
}
// Rewrite connections
std::vector<RTLIL::SigSig> new_connections;
for (const auto& conn : module->connections()) {
RTLIL::SigSig skip_conn, barrier_conn;
for (int i = 0; i < GetSize(conn.first); i++) {
auto& sigsig = skip(conn.first[i]) ? skip_conn : barrier_conn;
sigsig.first.append(conn.first[i]);
sigsig.second.append(conn.second[i]);
}
if (!skip_conn.first.empty())
new_connections.emplace_back(std::move(skip_conn));
if (!barrier_conn.first.empty())
module->addBarrier(NEW_ID, barrier_conn.second, barrier_conn.first);
}
module->new_connections(new_connections);
}
}
void remove_barriers(RTLIL::Design* design) {
for (auto* module : design->selected_modules()) {
std::vector<RTLIL::Cell*> barriers;
for (auto* cell : module->selected_cells())
if (cell->type == ID($barrier))
barriers.emplace_back(cell);
for (auto* cell : barriers) {
const auto lhs = cell->getPort(ID::Y), rhs = cell->getPort(ID::A);
module->connect(lhs, rhs);
module->remove(cell);
}
}
}
} OptBarriersPass;
PRIVATE_NAMESPACE_END

View File

@ -245,6 +245,7 @@ struct OptMergeWorker
ct.cell_types.erase(ID($anyconst));
ct.cell_types.erase(ID($allseq));
ct.cell_types.erase(ID($allconst));
ct.cell_types.erase(ID($barrier));
log("Finding identical cells in module `%s'.\n", module->name.c_str());
assign_map.set(module);

View File

@ -60,6 +60,7 @@ struct FlattenWorker
bool ignore_wb = false;
bool create_scopeinfo = true;
bool create_scopename = false;
bool barriers = false;
template<class T>
void map_attributes(RTLIL::Cell *cell, T *object, IdString orig_object_name)
@ -246,7 +247,27 @@ struct FlattenWorker
log_error("Cell port %s.%s.%s is driving constant bits: %s <= %s\n",
log_id(module), log_id(cell), log_id(port_it.first), log_signal(new_conn.first), log_signal(new_conn.second));
module->connect(new_conn);
if (barriers) {
// Drive public output wires with barriers and the rest with
// connections
RTLIL::SigSig skip_conn, barrier_conn;
for (int i = 0; i < GetSize(new_conn.first); i++) {
const auto lhs = new_conn.first[i], rhs = new_conn.second[i];
auto& sigsig = !lhs.is_wire() || !lhs.wire->name.isPublic() ? skip_conn : barrier_conn;
sigsig.first.append(lhs);
sigsig.second.append(rhs);
}
if (!skip_conn.first.empty())
module->connect(skip_conn);
if (!barrier_conn.first.empty())
module->addBarrier(NEW_ID, barrier_conn.second, barrier_conn.first);
} else {
module->connect(new_conn);
}
sigmap.add(new_conn.first, new_conn.second);
}
@ -345,6 +366,10 @@ struct FlattenPass : public Pass {
log(" with a public name the enclosing scope can be found via their\n");
log(" 'hdlname' attribute.\n");
log("\n");
log(" -barriers\n");
log(" Use $barrier cells to connect flattened modules to their surrounding\n");
log(" scope instead of connections for public wires.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
@ -367,6 +392,10 @@ struct FlattenPass : public Pass {
worker.create_scopename = true;
continue;
}
if (args[argidx] == "-barriers") {
worker.barriers = true;
continue;
}
break;
}
extra_args(args, argidx, design);

View File

@ -67,6 +67,11 @@ struct PrepPass : public ScriptPass
log(" -nokeepdc\n");
log(" do not call opt_* with -keepdc\n");
log("\n");
log(" -barriers\n");
log(" add optimization barriers to all public wires to preserve their structure.\n");
log(" this limits the optimizations that can be applied to the design to only\n");
log(" those involving private wires.\n");
log("\n");
log(" -run <from_label>[:<to_label>]\n");
log(" only run the commands between the labels (see below). an empty\n");
log(" from label is synonymous to 'begin', and empty to label is\n");
@ -79,7 +84,7 @@ struct PrepPass : public ScriptPass
}
string top_module, fsm_opts;
bool autotop, flatten, ifxmode, memxmode, nomemmode, nokeepdc, rdff;
bool autotop, flatten, ifxmode, memxmode, nomemmode, nokeepdc, rdff, barriers;
void clear_flags() override
{
@ -92,6 +97,7 @@ struct PrepPass : public ScriptPass
nomemmode = false;
nokeepdc = false;
rdff = false;
barriers = false;
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
@ -148,6 +154,10 @@ struct PrepPass : public ScriptPass
nokeepdc = true;
continue;
}
if (args[argidx] == "-barriers") {
barriers = true;
continue;
}
break;
}
extra_args(args, argidx, design);
@ -183,12 +193,16 @@ struct PrepPass : public ScriptPass
if (check_label("coarse"))
{
if (help_mode || barriers)
run("optbarriers", "(if -barriers)");
if (help_mode)
run("proc [-ifx]");
else
run(ifxmode ? "proc -ifx" : "proc");
if (help_mode || flatten)
run("flatten", "(if -flatten)");
if (help_mode)
run("flatten [-barriers]", "(if -flatten)");
else if (flatten)
run(barriers ? "flatten -barriers" : "flatten");
run("future");
run(nokeepdc ? "opt_expr" : "opt_expr -keepdc");
run("opt_clean");

View File

@ -108,6 +108,29 @@ endmodule
// --------------------------------------------------------
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
//-
//- $barrier (A, Y)
//* group unary
//-
//- A coarse-grain buffer cell type that acts as a barrier for optimizations.
//- Optimization passes are forbidden from rewriting patterns that include
//- this cell (by merging, constant propagation etc) with the exception of
//- opt_clean that can remove it if the output is unused.
//-
module \$barrier (A, Y);
parameter WIDTH = 0;
input [WIDTH-1:0] A;
output [WIDTH-1:0] Y;
assign Y = A;
endmodule
// --------------------------------------------------------
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
//-
//- $neg (A, Y)