diff options
Diffstat (limited to 'passes/opt')
-rw-r--r-- | passes/opt/Makefile.inc | 2 | ||||
-rw-r--r-- | passes/opt/opt.cc | 5 | ||||
-rw-r--r-- | passes/opt/opt_share.cc | 649 |
3 files changed, 655 insertions, 1 deletions
diff --git a/passes/opt/Makefile.inc b/passes/opt/Makefile.inc index ea3646330..eb07e9452 100644 --- a/passes/opt/Makefile.inc +++ b/passes/opt/Makefile.inc @@ -4,6 +4,7 @@ OBJS += passes/opt/opt_merge.o OBJS += passes/opt/opt_muxtree.o OBJS += passes/opt/opt_reduce.o OBJS += passes/opt/opt_rmdff.o +OBJS += passes/opt/opt_share.o OBJS += passes/opt/opt_clean.o OBJS += passes/opt/opt_expr.o @@ -16,4 +17,3 @@ OBJS += passes/opt/opt_lut.o OBJS += passes/opt/pmux2shiftx.o OBJS += passes/opt/muxpack.o endif - diff --git a/passes/opt/opt.cc b/passes/opt/opt.cc index e9a43e0f3..396819883 100644 --- a/passes/opt/opt.cc +++ b/passes/opt/opt.cc @@ -44,6 +44,7 @@ struct OptPass : public Pass { log(" opt_muxtree\n"); log(" opt_reduce [-fine] [-full]\n"); log(" opt_merge [-share_all]\n"); + log(" opt_share (-full only)\n"); log(" opt_rmdff [-keepdc] [-sat]\n"); log(" opt_clean [-purge]\n"); log(" opt_expr [-mux_undef] [-mux_bool] [-undriven] [-clkinv] [-fine] [-full] [-keepdc]\n"); @@ -70,6 +71,7 @@ struct OptPass : public Pass { std::string opt_reduce_args; std::string opt_merge_args; std::string opt_rmdff_args; + bool opt_share = false; bool fast_mode = false; log_header(design, "Executing OPT pass (performing simple optimizations).\n"); @@ -105,6 +107,7 @@ struct OptPass : public Pass { if (args[argidx] == "-full") { opt_expr_args += " -full"; opt_reduce_args += " -full"; + opt_share = true; continue; } if (args[argidx] == "-keepdc") { @@ -151,6 +154,8 @@ struct OptPass : public Pass { Pass::call(design, "opt_muxtree"); Pass::call(design, "opt_reduce" + opt_reduce_args); Pass::call(design, "opt_merge" + opt_merge_args); + if (opt_share) + Pass::call(design, "opt_share"); Pass::call(design, "opt_rmdff" + opt_rmdff_args); Pass::call(design, "opt_clean" + opt_clean_args); Pass::call(design, "opt_expr" + opt_expr_args); diff --git a/passes/opt/opt_share.cc b/passes/opt/opt_share.cc new file mode 100644 index 000000000..734cbcf81 --- /dev/null +++ b/passes/opt/opt_share.cc @@ -0,0 +1,649 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2012 Clifford Wolf <clifford@clifford.at> + * 2019 Bogdan Vukobratovic <bogdan.vukobratovic@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/log.h" +#include "kernel/register.h" +#include "kernel/rtlil.h" +#include "kernel/sigtools.h" +#include <algorithm> + +#include <stdio.h> +#include <stdlib.h> + +USING_YOSYS_NAMESPACE +PRIVATE_NAMESPACE_BEGIN + +SigMap assign_map; + +struct OpMuxConn { + RTLIL::SigSpec sig; + RTLIL::Cell *mux; + RTLIL::Cell *op; + int mux_port_id; + int mux_port_offset; + int op_outsig_offset; + + bool operator<(const OpMuxConn &other) const + { + if (mux != other.mux) + return mux < other.mux; + + if (mux_port_id != other.mux_port_id) + return mux_port_id < other.mux_port_id; + + return mux_port_offset < other.mux_port_offset; + } +}; + +// Helper class to track additiona information about a SigSpec, like whether it is signed and the semantics of the port it is connected to +struct ExtSigSpec { + RTLIL::SigSpec sig; + RTLIL::SigSpec sign; + bool is_signed; + RTLIL::IdString semantics; + + ExtSigSpec() {} + + ExtSigSpec(RTLIL::SigSpec s, RTLIL::SigSpec sign = RTLIL::Const(0, 1), bool is_signed = false, RTLIL::IdString semantics = RTLIL::IdString()) : sig(s), sign(sign), is_signed(is_signed), semantics(semantics) {} + + bool empty() const { return sig.empty(); } + + bool operator<(const ExtSigSpec &other) const + { + if (sig != other.sig) + return sig < other.sig; + + if (sign != other.sign) + return sign < other.sign; + + if (is_signed != other.is_signed) + return is_signed < other.is_signed; + + return semantics < other.semantics; + } + + bool operator==(const RTLIL::SigSpec &other) const { return (sign != RTLIL::Const(0, 1)) ? false : sig == other; } + bool operator==(const ExtSigSpec &other) const { return is_signed == other.is_signed && sign == other.sign && sig == other.sig && semantics == other.semantics; } +}; + +#define BITWISE_OPS ID($_AND_), ID($_NAND_), ID($_OR_), ID($_NOR_), ID($_XOR_), ID($_XNOR_), ID($_ANDNOT_), ID($_ORNOT_), ID($and), ID($or), ID($xor), ID($xnor) + +#define REDUCTION_OPS ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_xnor), ID($reduce_bool), ID($reduce_nand) + +#define LOGICAL_OPS ID($logic_and), ID($logic_or) + +#define SHIFT_OPS ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx) + +#define RELATIONAL_OPS ID($lt), ID($le), ID($eq), ID($ne), ID($eqx), ID($nex), ID($ge), ID($gt) + +bool cell_supported(RTLIL::Cell *cell) +{ + if (cell->type.in(ID($alu))) { + RTLIL::SigSpec sig_bi = cell->getPort(ID(BI)); + RTLIL::SigSpec sig_ci = cell->getPort(ID(CI)); + + if (sig_bi.is_fully_const() && sig_ci.is_fully_const() && sig_bi == sig_ci) + return true; + } else if (cell->type.in(LOGICAL_OPS, SHIFT_OPS, BITWISE_OPS, RELATIONAL_OPS, ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($concat))) { + return true; + } + + return false; +} + +std::map<IdString, IdString> mergeable_type_map{ + {ID($sub), ID($add)}, +}; + +bool mergeable(RTLIL::Cell *a, RTLIL::Cell *b) +{ + auto a_type = a->type; + if (mergeable_type_map.count(a_type)) + a_type = mergeable_type_map.at(a_type); + + auto b_type = b->type; + if (mergeable_type_map.count(b_type)) + b_type = mergeable_type_map.at(b_type); + + return a_type == b_type; +} + +RTLIL::IdString decode_port_semantics(RTLIL::Cell *cell, RTLIL::IdString port_name) +{ + if (cell->type.in(ID($lt), ID($le), ID($ge), ID($gt), ID($div), ID($mod), ID($concat), SHIFT_OPS) && port_name == ID(B)) + return port_name; + + return ""; +} + +RTLIL::SigSpec decode_port_sign(RTLIL::Cell *cell, RTLIL::IdString port_name) { + + if (cell->type == ID($alu) && port_name == ID(B)) + return cell->getPort(ID(BI)); + else if (cell->type == ID($sub) && port_name == ID(B)) + return RTLIL::Const(1, 1); + + return RTLIL::Const(0, 1); +} + +bool decode_port_signed(RTLIL::Cell *cell, RTLIL::IdString port_name) +{ + if (cell->type.in(BITWISE_OPS, LOGICAL_OPS)) + return false; + + if (cell->hasParam(port_name.str() + "_SIGNED")) + return cell->getParam(port_name.str() + "_SIGNED").as_bool(); + + return false; +} + +ExtSigSpec decode_port(RTLIL::Cell *cell, RTLIL::IdString port_name, SigMap *sigmap) +{ + auto sig = (*sigmap)(cell->getPort(port_name)); + + RTLIL::SigSpec sign = decode_port_sign(cell, port_name); + RTLIL::IdString semantics = decode_port_semantics(cell, port_name); + + bool is_signed = decode_port_signed(cell, port_name); + + return ExtSigSpec(sig, sign, is_signed, semantics); +} + +void merge_operators(RTLIL::Module *module, RTLIL::Cell *mux, const std::vector<OpMuxConn> &ports, const ExtSigSpec &operand) +{ + std::vector<ExtSigSpec> muxed_operands; + int max_width = 0; + for (const auto& p : ports) { + auto op = p.op; + + RTLIL::IdString muxed_port_name = ID(A); + if (decode_port(op, ID(A), &assign_map) == operand) + muxed_port_name = ID(B); + + auto operand = decode_port(op, muxed_port_name, &assign_map); + if (operand.sig.size() > max_width) + max_width = operand.sig.size(); + + muxed_operands.push_back(operand); + } + + auto shared_op = ports[0].op; + + if (std::any_of(muxed_operands.begin(), muxed_operands.end(), [&](ExtSigSpec &op) { return op.sign != muxed_operands[0].sign; })) + max_width = std::max(max_width, shared_op->getParam(ID(Y_WIDTH)).as_int()); + + + for (auto &operand : muxed_operands) + operand.sig.extend_u0(max_width, operand.is_signed); + + for (const auto& p : ports) { + auto op = p.op; + if (op == shared_op) + continue; + module->remove(op); + } + + for (auto &muxed_op : muxed_operands) + if (muxed_op.sign != muxed_operands[0].sign) + muxed_op = ExtSigSpec(module->Neg(NEW_ID, muxed_op.sig, muxed_op.is_signed)); + + RTLIL::SigSpec mux_y = mux->getPort(ID(Y)); + RTLIL::SigSpec mux_a = mux->getPort(ID(A)); + RTLIL::SigSpec mux_b = mux->getPort(ID(B)); + RTLIL::SigSpec mux_s = mux->getPort(ID(S)); + + RTLIL::SigSpec shared_pmux_a = RTLIL::Const(RTLIL::State::Sx, max_width); + RTLIL::SigSpec shared_pmux_b; + RTLIL::SigSpec shared_pmux_s; + + int conn_width = ports[0].sig.size(); + int conn_offset = ports[0].mux_port_offset; + + shared_op->setPort(ID(Y), shared_op->getPort(ID(Y)).extract(0, conn_width)); + + if (mux->type == ID($pmux)) { + shared_pmux_s = RTLIL::SigSpec(); + + for (const auto &p : ports) { + shared_pmux_s.append(mux_s[p.mux_port_id]); + mux_b.replace(p.mux_port_id * mux_a.size() + conn_offset, shared_op->getPort(ID(Y))); + } + } else { + shared_pmux_s = RTLIL::SigSpec{mux_s, module->Not(NEW_ID, mux_s)}; + mux_a.replace(conn_offset, shared_op->getPort(ID(Y))); + mux_b.replace(conn_offset, shared_op->getPort(ID(Y))); + } + + mux->setPort(ID(A), mux_a); + mux->setPort(ID(B), mux_b); + mux->setPort(ID(Y), mux_y); + mux->setPort(ID(S), mux_s); + + for (const auto &op : muxed_operands) + shared_pmux_b.append(op.sig); + + auto mux_to_oper = module->Pmux(NEW_ID, shared_pmux_a, shared_pmux_b, shared_pmux_s); + + if (shared_op->type.in(ID($alu))) { + RTLIL::SigSpec alu_x = shared_op->getPort(ID(X)); + RTLIL::SigSpec alu_co = shared_op->getPort(ID(CO)); + + shared_op->setPort(ID(X), alu_x.extract(0, conn_width)); + shared_op->setPort(ID(CO), alu_co.extract(0, conn_width)); + } + + shared_op->setParam(ID(Y_WIDTH), conn_width); + + if (decode_port(shared_op, ID(A), &assign_map) == operand) { + shared_op->setPort(ID(B), mux_to_oper); + shared_op->setParam(ID(B_WIDTH), max_width); + } else { + shared_op->setPort(ID(A), mux_to_oper); + shared_op->setParam(ID(A_WIDTH), max_width); + } +} + +typedef struct { + RTLIL::Cell *mux; + std::vector<OpMuxConn> ports; + ExtSigSpec shared_operand; +} merged_op_t; + + +template <typename T> void remove_val(std::vector<T> &v, const std::vector<T> &vals) +{ + auto val_iter = vals.rbegin(); + for (auto i = v.rbegin(); i != v.rend(); ++i) + if ((val_iter != vals.rend()) && (*i == *val_iter)) { + v.erase(i.base() - 1); + ++val_iter; + } +} + +void check_muxed_operands(std::vector<const OpMuxConn *> &ports, const ExtSigSpec &shared_operand) +{ + auto it = ports.begin(); + ExtSigSpec seed; + + while (it != ports.end()) { + auto p = *it; + auto op = p->op; + + RTLIL::IdString muxed_port_name = ID(A); + if (decode_port(op, ID(A), &assign_map) == shared_operand) { + muxed_port_name = ID(B); + } + + auto operand = decode_port(op, muxed_port_name, &assign_map); + + if (seed.empty()) + seed = operand; + + if (operand.is_signed != seed.is_signed) { + ports.erase(it); + } else { + ++it; + } + } +} + +ExtSigSpec find_shared_operand(const OpMuxConn* seed, std::vector<const OpMuxConn *> &ports, const std::map<ExtSigSpec, std::set<RTLIL::Cell *>> &operand_to_users) +{ + std::set<RTLIL::Cell *> ops_using_operand; + std::set<RTLIL::Cell *> ops_set; + for(const auto& p: ports) + ops_set.insert(p->op); + + ExtSigSpec oper; + + auto op_a = seed->op; + + for (RTLIL::IdString port_name : {ID(A), ID(B)}) { + oper = decode_port(op_a, port_name, &assign_map); + auto operand_users = operand_to_users.at(oper); + + if (operand_users.size() == 1) + continue; + + ops_using_operand.clear(); + for (auto mux_ops: ops_set) + if (operand_users.count(mux_ops)) + ops_using_operand.insert(mux_ops); + + if (ops_using_operand.size() > 1) { + ports.erase(std::remove_if(ports.begin(), ports.end(), [&](const OpMuxConn *p) { return !ops_using_operand.count(p->op); }), + ports.end()); + return oper; + } + } + + return ExtSigSpec(); +} + +dict<RTLIL::SigSpec, OpMuxConn> find_valid_op_mux_conns(RTLIL::Module *module, dict<RTLIL::SigBit, RTLIL::SigSpec> &op_outbit_to_outsig, + dict<RTLIL::SigSpec, RTLIL::Cell *> outsig_to_operator, + dict<RTLIL::SigBit, RTLIL::SigSpec> &op_aux_to_outsig) +{ + dict<RTLIL::SigSpec, int> op_outsig_user_track; + dict<RTLIL::SigSpec, OpMuxConn> op_mux_conn_map; + + std::function<void(RTLIL::SigSpec)> remove_outsig = [&](RTLIL::SigSpec outsig) { + for (auto op_outbit : outsig) + op_outbit_to_outsig.erase(op_outbit); + + if (op_mux_conn_map.count(outsig)) + op_mux_conn_map.erase(outsig); + }; + + std::function<void(RTLIL::SigBit)> remove_outsig_from_aux_bit = [&](RTLIL::SigBit auxbit) { + auto aux_outsig = op_aux_to_outsig.at(auxbit); + auto op = outsig_to_operator.at(aux_outsig); + auto op_outsig = assign_map(op->getPort(ID(Y))); + remove_outsig(op_outsig); + + for (auto aux_outbit : aux_outsig) + op_aux_to_outsig.erase(aux_outbit); + }; + + std::function<void(RTLIL::Cell *)> find_op_mux_conns = [&](RTLIL::Cell *mux) { + RTLIL::SigSpec sig; + int mux_port_size; + + if (mux->type.in(ID($mux), ID($_MUX_))) { + mux_port_size = mux->getPort(ID(A)).size(); + sig = RTLIL::SigSpec{mux->getPort(ID(B)), mux->getPort(ID(A))}; + } else { + mux_port_size = mux->getPort(ID(A)).size(); + sig = mux->getPort(ID(B)); + } + + auto mux_insig = assign_map(sig); + + for (int i = 0; i < mux_insig.size(); ++i) { + if (op_aux_to_outsig.count(mux_insig[i])) { + remove_outsig_from_aux_bit(mux_insig[i]); + continue; + } + + if (!op_outbit_to_outsig.count(mux_insig[i])) + continue; + + auto op_outsig = op_outbit_to_outsig.at(mux_insig[i]); + + if (op_mux_conn_map.count(op_outsig)) { + remove_outsig(op_outsig); + continue; + } + + int mux_port_id = i / mux_port_size; + int mux_port_offset = i % mux_port_size; + + int op_outsig_offset; + for (op_outsig_offset = 0; op_outsig[op_outsig_offset] != mux_insig[i]; ++op_outsig_offset) + ; + + int j = op_outsig_offset; + do { + if (!op_outbit_to_outsig.count(mux_insig[i])) + break; + + if (op_outbit_to_outsig.at(mux_insig[i]) != op_outsig) + break; + + ++i; + ++j; + } while ((i / mux_port_size == mux_port_id) && (j < op_outsig.size())); + + int op_conn_width = j - op_outsig_offset; + OpMuxConn inp = { + op_outsig.extract(op_outsig_offset, op_conn_width), + mux, + outsig_to_operator.at(op_outsig), + mux_port_id, + mux_port_offset, + op_outsig_offset, + }; + + op_mux_conn_map[op_outsig] = inp; + + --i; + } + }; + + std::function<void(RTLIL::SigSpec)> remove_connected_ops = [&](RTLIL::SigSpec sig) { + auto mux_insig = assign_map(sig); + for (auto outbit : mux_insig) { + if (op_aux_to_outsig.count(outbit)) { + remove_outsig_from_aux_bit(outbit); + continue; + } + + if (!op_outbit_to_outsig.count(outbit)) + continue; + + remove_outsig(op_outbit_to_outsig.at(outbit)); + } + }; + + for (auto cell : module->cells()) { + if (cell->type.in(ID($mux), ID($_MUX_), ID($pmux))) { + remove_connected_ops(cell->getPort(ID(S))); + find_op_mux_conns(cell); + } else { + for (auto &conn : cell->connections()) + if (cell->input(conn.first)) + remove_connected_ops(conn.second); + } + } + + for (auto w : module->wires()) { + if (!w->port_output) + continue; + + remove_connected_ops(w); + } + + return op_mux_conn_map; +} + +struct OptSharePass : public Pass { + OptSharePass() : Pass("opt_share", "merge mutually exclusive cells of the same type that share an input signal") {} + void help() YS_OVERRIDE + { + // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| + log("\n"); + log(" opt_share [selection]\n"); + log("\n"); + + log("This pass identifies mutually exclusive cells of the same type that:\n"); + log(" (a) share an input signal,\n"); + log(" (b) drive the same $mux, $_MUX_, or $pmux multiplexing cell,\n"); + log("\n"); + log("allowing the cell to be merged and the multiplexer to be moved from\n"); + log("multiplexing its output to multiplexing the non-shared input signals.\n"); + log("\n"); + } + void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE + { + + log_header(design, "Executing OPT_SHARE pass.\n"); + + extra_args(args, 1, design); + for (auto module : design->selected_modules()) { + assign_map.clear(); + assign_map.set(module); + + std::map<ExtSigSpec, std::set<RTLIL::Cell *>> operand_to_users; + dict<RTLIL::SigSpec, RTLIL::Cell *> outsig_to_operator; + dict<RTLIL::SigBit, RTLIL::SigSpec> op_outbit_to_outsig; + dict<RTLIL::SigBit, RTLIL::SigSpec> op_aux_to_outsig; + bool any_shared_operands = false; + std::vector<ExtSigSpec> op_insigs; + + for (auto cell : module->cells()) { + if (!cell_supported(cell)) + continue; + + if (cell->type == ID($alu)) { + for (RTLIL::IdString port_name : {ID(X), ID(CO)}) { + auto mux_insig = assign_map(cell->getPort(port_name)); + outsig_to_operator[mux_insig] = cell; + for (auto outbit : mux_insig) + op_aux_to_outsig[outbit] = mux_insig; + } + } + + auto mux_insig = assign_map(cell->getPort(ID(Y))); + outsig_to_operator[mux_insig] = cell; + for (auto outbit : mux_insig) + op_outbit_to_outsig[outbit] = mux_insig; + + for (RTLIL::IdString port_name : {ID(A), ID(B)}) { + auto op_insig = decode_port(cell, port_name, &assign_map); + op_insigs.push_back(op_insig); + operand_to_users[op_insig].insert(cell); + if (operand_to_users[op_insig].size() > 1) + any_shared_operands = true; + } + } + + if (!any_shared_operands) + continue; + + // Operator outputs need to be exclusively connected to the $mux inputs in order to be mergeable. Hence we count to + // how many points are operator output bits connected. + dict<RTLIL::SigSpec, OpMuxConn> op_mux_conn_map = + find_valid_op_mux_conns(module, op_outbit_to_outsig, outsig_to_operator, op_aux_to_outsig); + + // Group op connections connected to same ports of the same $mux. Sort them in ascending order of their port offset + dict<RTLIL::Cell*, std::vector<std::set<OpMuxConn>>> mux_port_op_conns; + for (auto& val: op_mux_conn_map) { + OpMuxConn p = val.second; + auto& mux_port_conns = mux_port_op_conns[p.mux]; + + if (mux_port_conns.size() == 0) { + int mux_port_num; + + if (p.mux->type.in(ID($mux), ID($_MUX_))) + mux_port_num = 2; + else + mux_port_num = p.mux->getPort(ID(S)).size(); + + mux_port_conns.resize(mux_port_num); + } + + mux_port_conns[p.mux_port_id].insert(p); + } + + std::vector<merged_op_t> merged_ops; + for (auto& val: mux_port_op_conns) { + + RTLIL::Cell* cell = val.first; + auto &mux_port_conns = val.second; + + const OpMuxConn *seed = NULL; + + // Look through the bits of the $mux inputs and see which of them are connected to the operator + // results. Operator results can be concatenated with other signals before led to the $mux. + while (true) { + + // Remove either the merged ports from the last iteration or the seed that failed to yield a merger + if (seed != NULL) { + mux_port_conns[seed->mux_port_id].erase(*seed); + seed = NULL; + } + + // For a new merger, find the seed op connection that starts at lowest port offset among port connections + for (auto &port_conns : mux_port_conns) { + if (!port_conns.size()) + continue; + + const OpMuxConn *next_p = &(*port_conns.begin()); + + if ((seed == NULL) || (seed->mux_port_offset > next_p->mux_port_offset)) + seed = next_p; + } + + // Cannot find the seed -> nothing to do for this $mux anymore + if (seed == NULL) + break; + + // Find all other op connections that start from the same port offset, and whose ops can be merged with the seed op + std::vector<const OpMuxConn *> mergeable_conns; + for (auto &port_conns : mux_port_conns) { + if (!port_conns.size()) + continue; + + const OpMuxConn *next_p = &(*port_conns.begin()); + + if ((next_p->op_outsig_offset == seed->op_outsig_offset) && + (next_p->mux_port_offset == seed->mux_port_offset) && mergeable(next_p->op, seed->op) && + next_p->sig.size() == seed->sig.size()) + mergeable_conns.push_back(next_p); + } + + // We need at least two mergeable connections for the merger + if (mergeable_conns.size() < 2) + continue; + + // Filter mergeable connections whose ops share an operand with seed connection's op + auto shared_operand = find_shared_operand(seed, mergeable_conns, operand_to_users); + + if (shared_operand.empty()) + continue; + + check_muxed_operands(mergeable_conns, shared_operand); + + if (mergeable_conns.size() < 2) + continue; + + // Remember the combination for the merger + std::vector<OpMuxConn> merged_ports; + for (auto p : mergeable_conns) { + merged_ports.push_back(*p); + mux_port_conns[p->mux_port_id].erase(*p); + } + + seed = NULL; + + merged_ops.push_back(merged_op_t{cell, merged_ports, shared_operand}); + + design->scratchpad_set_bool("opt.did_something", true); + } + + } + + for (auto &shared : merged_ops) { + log(" Found cells that share an operand and can be merged by moving the %s %s in front " + "of " + "them:\n", + log_id(shared.mux->type), log_id(shared.mux)); + for (const auto& op : shared.ports) + log(" %s\n", log_id(op.op)); + log("\n"); + + merge_operators(module, shared.mux, shared.ports, shared.shared_operand); + } + } + } + +} OptSharePass; + +PRIVATE_NAMESPACE_END |