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author | Marcelina Kościelnicka <mwk@0x04.net> | 2021-08-04 00:02:16 +0200 |
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committer | Marcelina Kościelnicka <mwk@0x04.net> | 2021-08-09 16:54:35 +0200 |
commit | d25b9088c83ba68b938ef9f0d97793a08001a9fe (patch) | |
tree | 850d768b062d231f0ff7d9fbc3bab8d642a861c6 /kernel/qcsat.cc | |
parent | d8fcf1ab2568ae88aa3a2c9548578b899cc4d383 (diff) | |
download | yosys-d25b9088c83ba68b938ef9f0d97793a08001a9fe.tar.gz yosys-d25b9088c83ba68b938ef9f0d97793a08001a9fe.tar.bz2 yosys-d25b9088c83ba68b938ef9f0d97793a08001a9fe.zip |
Refactor common parts of SAT-using optimizations into a helper.
This also aligns the functionality:
- in all cases, the onehot attribute is used to create appropriate
constraints (previously, opt_dff didn't do it at all, and share
created one-hot constraints based on $pmux presence alone, which
is unsound)
- in all cases, shift and mul/div/pow cells are now skipped when
importing the SAT problem (previously only memory_share did this)
— this avoids creating clauses for hard cells that are unlikely
to help with proving the UNSATness needed for optimization
Diffstat (limited to 'kernel/qcsat.cc')
-rw-r--r-- | kernel/qcsat.cc | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/kernel/qcsat.cc b/kernel/qcsat.cc new file mode 100644 index 000000000..b7da958db --- /dev/null +++ b/kernel/qcsat.cc @@ -0,0 +1,102 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2021 Marcelina Kościelnicka <mwk@0x04.net> + * + * 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/qcsat.h" + +USING_YOSYS_NAMESPACE + +std::vector<int> QuickConeSat::importSig(SigSpec sig) +{ + sig = modwalker.sigmap(sig); + for (auto bit : sig) + bits_queue.insert(bit); + return satgen.importSigSpec(sig); +} + +int QuickConeSat::importSigBit(SigBit bit) +{ + bit = modwalker.sigmap(bit); + bits_queue.insert(bit); + return satgen.importSigBit(bit); +} + +void QuickConeSat::prepare() +{ + while (!bits_queue.empty()) + { + pool<ModWalker::PortBit> portbits; + modwalker.get_drivers(portbits, bits_queue); + + for (auto bit : bits_queue) + if (bit.wire && bit.wire->get_bool_attribute(ID::onehot) && !imported_onehot.count(bit.wire)) + { + std::vector<int> bits = satgen.importSigSpec(bit.wire); + for (int i : bits) + for (int j : bits) + if (i != j) + ez->assume(ez->NOT(i), j); + imported_onehot.insert(bit.wire); + } + + bits_queue.clear(); + + for (auto &pbit : portbits) + { + if (imported_cells.count(pbit.cell)) + continue; + if (cell_complexity(pbit.cell) > max_cell_complexity) + continue; + if (max_cell_outs && GetSize(modwalker.cell_outputs[pbit.cell]) > max_cell_outs) + continue; + auto &inputs = modwalker.cell_inputs[pbit.cell]; + bits_queue.insert(inputs.begin(), inputs.end()); + satgen.importCell(pbit.cell); + imported_cells.insert(pbit.cell); + } + + if (max_cell_count && GetSize(imported_cells) > max_cell_count) + break; + } +} + +int QuickConeSat::cell_complexity(RTLIL::Cell *cell) +{ + if (cell->type.in(ID($concat), ID($slice), ID($pos), 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($reduce_xor), + ID($reduce_xnor), ID($reduce_bool), + ID($logic_not), ID($logic_and), ID($logic_or), + ID($eq), ID($ne), ID($eqx), ID($nex), ID($fa), + ID($mux), ID($pmux), ID($lut), ID($sop), + ID($_NOT_), ID($_AND_), ID($_NAND_), ID($_OR_), ID($_NOR_), + ID($_XOR_), ID($_XNOR_), ID($_ANDNOT_), ID($_ORNOT_), + ID($_MUX_), ID($_NMUX_), ID($_MUX4_), ID($_MUX8_), ID($_MUX16_), + ID($_AOI3_), ID($_OAI3_), ID($_AOI4_), ID($_OAI4_))) + return 1; + if (cell->type.in(ID($neg), ID($add), ID($sub), ID($alu), ID($lcu), + ID($lt), ID($le), ID($gt), ID($ge))) + return 2; + if (cell->type.in(ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx))) + return 3; + if (cell->type.in(ID($mul), ID($macc), ID($div), ID($mod), ID($divfloor), ID($modfloor), ID($pow))) + return 4; + // Unknown cell. + return 5; +} |