mirror of
				https://github.com/YosysHQ/yosys
				synced 2025-11-03 21:09:12 +00:00 
			
		
		
		
	
		
			
				
	
	
		
			604 lines
		
	
	
	
		
			18 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			604 lines
		
	
	
	
		
			18 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
 | 
						|
 *  yosys -- Yosys Open SYnthesis Suite
 | 
						|
 *
 | 
						|
 *  Copyright (C) 2018  whitequark <whitequark@whitequark.org>
 | 
						|
 *
 | 
						|
 *  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"
 | 
						|
#include "kernel/modtools.h"
 | 
						|
 | 
						|
USING_YOSYS_NAMESPACE
 | 
						|
PRIVATE_NAMESPACE_BEGIN
 | 
						|
 | 
						|
struct dlogic_t {
 | 
						|
	IdString cell_type;
 | 
						|
	// LUT input idx -> hard cell's port name
 | 
						|
	dict<int, IdString> lut_input_port;
 | 
						|
};
 | 
						|
 | 
						|
struct OptLutWorker
 | 
						|
{
 | 
						|
	const std::vector<dlogic_t> &dlogic;
 | 
						|
	RTLIL::Module *module;
 | 
						|
	ModIndex index;
 | 
						|
	SigMap sigmap;
 | 
						|
 | 
						|
	pool<RTLIL::Cell*> luts;
 | 
						|
	dict<RTLIL::Cell*, int> luts_arity;
 | 
						|
	dict<RTLIL::Cell*, pool<std::pair<int, RTLIL::Cell*>>> luts_dlogics;
 | 
						|
	dict<RTLIL::Cell*, pool<int>> luts_dlogic_inputs;
 | 
						|
 | 
						|
	int eliminated_count = 0, combined_count = 0;
 | 
						|
 | 
						|
	bool evaluate_lut(RTLIL::Cell *lut, dict<SigBit, bool> inputs)
 | 
						|
	{
 | 
						|
		SigSpec lut_input = sigmap(lut->getPort(ID::A));
 | 
						|
		int lut_width = lut->getParam(ID::WIDTH).as_int();
 | 
						|
		Const lut_table = lut->getParam(ID::LUT);
 | 
						|
		int lut_index = 0;
 | 
						|
 | 
						|
		for (int i = 0; i < lut_width; i++)
 | 
						|
		{
 | 
						|
			SigBit input = sigmap(lut_input[i]);
 | 
						|
			if (inputs.count(input))
 | 
						|
			{
 | 
						|
				lut_index |= inputs[input] << i;
 | 
						|
			}
 | 
						|
			else
 | 
						|
			{
 | 
						|
				lut_index |= SigSpec(lut_input[i]).as_bool() << i;
 | 
						|
			}
 | 
						|
		}
 | 
						|
 | 
						|
		return lut_table.extract(lut_index).as_bool();
 | 
						|
	}
 | 
						|
 | 
						|
	void show_stats_by_arity()
 | 
						|
	{
 | 
						|
		dict<int, int> arity_counts;
 | 
						|
		std::vector<int> dlogic_counts(dlogic.size());
 | 
						|
		int max_arity = 0;
 | 
						|
 | 
						|
		for (auto lut_arity : luts_arity)
 | 
						|
		{
 | 
						|
			max_arity = max(max_arity, lut_arity.second);
 | 
						|
			arity_counts[lut_arity.second]++;
 | 
						|
		}
 | 
						|
 | 
						|
		for (auto &lut_dlogics : luts_dlogics)
 | 
						|
		{
 | 
						|
			for (auto &lut_dlogic : lut_dlogics.second)
 | 
						|
			{
 | 
						|
				dlogic_counts[lut_dlogic.first]++;
 | 
						|
			}
 | 
						|
		}
 | 
						|
 | 
						|
		log("Number of LUTs: %8d\n", GetSize(luts));
 | 
						|
		for (int arity = 1; arity <= max_arity; arity++)
 | 
						|
		{
 | 
						|
			if (arity_counts[arity])
 | 
						|
				log("  %d-LUT %16d\n", arity, arity_counts[arity]);
 | 
						|
		}
 | 
						|
		for (int i = 0; i < GetSize(dlogic); i++)
 | 
						|
		{
 | 
						|
			log("  with %-12s (#%d) %4d\n", dlogic[i].cell_type.c_str(), i, dlogic_counts[i]);
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	OptLutWorker(const std::vector<dlogic_t> &dlogic, RTLIL::Module *module, int limit) :
 | 
						|
		dlogic(dlogic), module(module), index(module), sigmap(module)
 | 
						|
	{
 | 
						|
		log("Discovering LUTs.\n");
 | 
						|
		for (auto cell : module->selected_cells())
 | 
						|
		{
 | 
						|
			if (cell->type == ID($lut))
 | 
						|
			{
 | 
						|
				if (cell->has_keep_attr())
 | 
						|
					continue;
 | 
						|
				SigBit lut_output = cell->getPort(ID::Y);
 | 
						|
				if (lut_output.wire->get_bool_attribute(ID::keep))
 | 
						|
					continue;
 | 
						|
 | 
						|
				int lut_width = cell->getParam(ID::WIDTH).as_int();
 | 
						|
				SigSpec lut_input = cell->getPort(ID::A);
 | 
						|
				int lut_arity = 0;
 | 
						|
 | 
						|
				log_debug("Found $lut\\WIDTH=%d cell %s.%s.\n", lut_width, log_id(module), log_id(cell));
 | 
						|
				luts.insert(cell);
 | 
						|
 | 
						|
				// First, find all dedicated logic we're connected to. This results in an overapproximation
 | 
						|
				// of such connections.
 | 
						|
				pool<std::pair<int, RTLIL::Cell*>> lut_all_dlogics;
 | 
						|
				for (int i = 0; i < lut_width; i++)
 | 
						|
				{
 | 
						|
					SigBit bit = lut_input[i];
 | 
						|
					for (auto &port : index.query_ports(bit))
 | 
						|
					{
 | 
						|
						for (int j = 0; j < GetSize(dlogic); j++)
 | 
						|
						{
 | 
						|
							if (dlogic[j].cell_type == port.cell->type)
 | 
						|
							{
 | 
						|
								if (port.port == dlogic[j].lut_input_port.at(i, IdString()))
 | 
						|
								{
 | 
						|
									lut_all_dlogics.insert({j, port.cell});
 | 
						|
								}
 | 
						|
							}
 | 
						|
						}
 | 
						|
					}
 | 
						|
				}
 | 
						|
 | 
						|
				// Second, make sure that the connection to dedicated logic is legal. If it is not legal,
 | 
						|
				// it means one of the two things:
 | 
						|
				//   * The connection is spurious. I.e. this is dedicated logic that will be packed
 | 
						|
				//     with some other LUT, and it just happens to be connected to this LUT as well.
 | 
						|
				//   * The connection is illegal.
 | 
						|
				// In either of these cases, we don't need to concern ourselves with preserving the connection
 | 
						|
				// between this LUT and this dedicated logic cell.
 | 
						|
				pool<std::pair<int, RTLIL::Cell*>> lut_legal_dlogics;
 | 
						|
				pool<int> lut_dlogic_inputs;
 | 
						|
				for (auto lut_dlogic : lut_all_dlogics)
 | 
						|
				{
 | 
						|
					auto &dlogic_map = dlogic[lut_dlogic.first].lut_input_port;
 | 
						|
					bool legal = true;
 | 
						|
					for (auto &dlogic_conn : dlogic_map)
 | 
						|
					{
 | 
						|
						if (lut_width <= dlogic_conn.first)
 | 
						|
						{
 | 
						|
							log_debug("  LUT has illegal connection to %s cell %s.%s.\n", lut_dlogic.second->type.c_str(), log_id(module), log_id(lut_dlogic.second));
 | 
						|
							log_debug("    LUT input A[%d] not present.\n", dlogic_conn.first);
 | 
						|
							legal = false;
 | 
						|
							break;
 | 
						|
						}
 | 
						|
						if (sigmap(lut_input[dlogic_conn.first]) != sigmap(lut_dlogic.second->getPort(dlogic_conn.second)))
 | 
						|
						{
 | 
						|
							log_debug("  LUT has illegal connection to %s cell %s.%s.\n", lut_dlogic.second->type.c_str(), log_id(module), log_id(lut_dlogic.second));
 | 
						|
							log_debug("    LUT input A[%d] (wire %s) not connected to %s port %s (wire %s).\n", dlogic_conn.first, log_signal(lut_input[dlogic_conn.first]), lut_dlogic.second->type.c_str(), dlogic_conn.second.c_str(), log_signal(lut_dlogic.second->getPort(dlogic_conn.second)));
 | 
						|
							legal = false;
 | 
						|
							break;
 | 
						|
						}
 | 
						|
					}
 | 
						|
 | 
						|
					if (legal)
 | 
						|
					{
 | 
						|
						log_debug("  LUT has legal connection to %s cell %s.%s.\n", lut_dlogic.second->type.c_str(), log_id(module), log_id(lut_dlogic.second));
 | 
						|
						lut_legal_dlogics.insert(lut_dlogic);
 | 
						|
						for (auto &dlogic_conn : dlogic_map)
 | 
						|
							lut_dlogic_inputs.insert(dlogic_conn.first);
 | 
						|
					}
 | 
						|
				}
 | 
						|
 | 
						|
				// Third, determine LUT arity. An n-wide LUT that has k constant inputs and m inputs shared with dedicated
 | 
						|
				// logic implements an (n-k-m)-ary function.
 | 
						|
				for (int i = 0; i < lut_width; i++)
 | 
						|
				{
 | 
						|
					SigBit bit = lut_input[i];
 | 
						|
					if (bit.wire || lut_dlogic_inputs.count(i))
 | 
						|
						lut_arity++;
 | 
						|
				}
 | 
						|
 | 
						|
				log_debug("  Cell implements a %d-LUT.\n", lut_arity);
 | 
						|
				luts_arity[cell] = lut_arity;
 | 
						|
				luts_dlogics[cell] = lut_legal_dlogics;
 | 
						|
				luts_dlogic_inputs[cell] = lut_dlogic_inputs;
 | 
						|
			}
 | 
						|
		}
 | 
						|
		show_stats_by_arity();
 | 
						|
 | 
						|
		log("\n");
 | 
						|
		log("Eliminating LUTs.\n");
 | 
						|
		pool<RTLIL::Cell*> worklist = luts;
 | 
						|
		while (worklist.size())
 | 
						|
		{
 | 
						|
			if (limit == 0)
 | 
						|
			{
 | 
						|
				log("Limit reached.\n");
 | 
						|
				break;
 | 
						|
			}
 | 
						|
 | 
						|
			auto lut = worklist.pop();
 | 
						|
			SigSpec lut_input = sigmap(lut->getPort(ID::A));
 | 
						|
			pool<int> &lut_dlogic_inputs = luts_dlogic_inputs[lut];
 | 
						|
 | 
						|
			vector<SigBit> lut_inputs;
 | 
						|
			for (auto &bit : lut_input)
 | 
						|
			{
 | 
						|
				if (bit.wire)
 | 
						|
					lut_inputs.push_back(sigmap(bit));
 | 
						|
			}
 | 
						|
 | 
						|
			bool const0_match = true;
 | 
						|
			bool const1_match = true;
 | 
						|
			vector<bool> input_matches;
 | 
						|
			for (size_t i = 0; i < lut_inputs.size(); i++)
 | 
						|
				input_matches.push_back(true);
 | 
						|
 | 
						|
			for (int eval = 0; eval < 1 << lut_inputs.size(); eval++)
 | 
						|
			{
 | 
						|
				dict<SigBit, bool> eval_inputs;
 | 
						|
				for (size_t i = 0; i < lut_inputs.size(); i++)
 | 
						|
					eval_inputs[lut_inputs[i]] = (eval >> i) & 1;
 | 
						|
				bool value = evaluate_lut(lut, eval_inputs);
 | 
						|
				if (value != 0)
 | 
						|
					const0_match = false;
 | 
						|
				if (value != 1)
 | 
						|
					const1_match = false;
 | 
						|
				for (size_t i = 0; i < lut_inputs.size(); i++)
 | 
						|
				{
 | 
						|
					if (value != eval_inputs[lut_inputs[i]])
 | 
						|
						input_matches[i] = false;
 | 
						|
				}
 | 
						|
			}
 | 
						|
 | 
						|
			int input_match = -1;
 | 
						|
			for (size_t i = 0; i < lut_inputs.size(); i++)
 | 
						|
				if (input_matches[i])
 | 
						|
					input_match = i;
 | 
						|
 | 
						|
			if (const0_match || const1_match || input_match != -1)
 | 
						|
			{
 | 
						|
				log_debug("Found redundant cell %s.%s.\n", log_id(module), log_id(lut));
 | 
						|
 | 
						|
				SigBit value;
 | 
						|
				if (const0_match)
 | 
						|
				{
 | 
						|
					log_debug("  Cell evaluates constant 0.\n");
 | 
						|
					value = State::S0;
 | 
						|
				}
 | 
						|
				if (const1_match)
 | 
						|
				{
 | 
						|
					log_debug("  Cell evaluates constant 1.\n");
 | 
						|
					value = State::S1;
 | 
						|
				}
 | 
						|
				if (input_match != -1) {
 | 
						|
					log_debug("  Cell evaluates signal %s.\n", log_signal(lut_inputs[input_match]));
 | 
						|
					value = lut_inputs[input_match];
 | 
						|
				}
 | 
						|
 | 
						|
				if (lut_dlogic_inputs.size())
 | 
						|
					log_debug("  Not eliminating cell (connected to dedicated logic).\n");
 | 
						|
				else
 | 
						|
				{
 | 
						|
					SigSpec lut_output = lut->getPort(ID::Y);
 | 
						|
					for (auto &port : index.query_ports(lut_output))
 | 
						|
					{
 | 
						|
						if (port.cell != lut && luts.count(port.cell))
 | 
						|
							worklist.insert(port.cell);
 | 
						|
					}
 | 
						|
 | 
						|
					module->connect(lut_output, value);
 | 
						|
					sigmap.add(lut_output, value);
 | 
						|
 | 
						|
					luts.erase(lut);
 | 
						|
					luts_arity.erase(lut);
 | 
						|
					luts_dlogics.erase(lut);
 | 
						|
					luts_dlogic_inputs.erase(lut);
 | 
						|
 | 
						|
					module->remove(lut);
 | 
						|
					
 | 
						|
					eliminated_count++;
 | 
						|
					if (limit > 0)
 | 
						|
						limit--;
 | 
						|
				}
 | 
						|
			}
 | 
						|
		}
 | 
						|
		show_stats_by_arity();
 | 
						|
 | 
						|
		log("\n");
 | 
						|
		log("Combining LUTs.\n");
 | 
						|
		worklist = luts;
 | 
						|
		while (worklist.size())
 | 
						|
		{
 | 
						|
			if (limit == 0)
 | 
						|
			{
 | 
						|
				log("Limit reached.\n");
 | 
						|
				break;
 | 
						|
			}
 | 
						|
 | 
						|
			auto lutA = worklist.pop();
 | 
						|
			SigSpec lutA_input = sigmap(lutA->getPort(ID::A));
 | 
						|
			SigSpec lutA_output = sigmap(lutA->getPort(ID::Y)[0]);
 | 
						|
			int lutA_width = lutA->getParam(ID::WIDTH).as_int();
 | 
						|
			int lutA_arity = luts_arity[lutA];
 | 
						|
			pool<int> &lutA_dlogic_inputs = luts_dlogic_inputs[lutA];
 | 
						|
 | 
						|
			auto lutA_output_ports = index.query_ports(lutA->getPort(ID::Y));
 | 
						|
			if (lutA_output_ports.size() != 2)
 | 
						|
				continue;
 | 
						|
 | 
						|
			for (auto &port : lutA_output_ports)
 | 
						|
			{
 | 
						|
				if (port.cell == lutA)
 | 
						|
					continue;
 | 
						|
 | 
						|
				if (luts.count(port.cell))
 | 
						|
				{
 | 
						|
					auto lutB = port.cell;
 | 
						|
					SigSpec lutB_input = sigmap(lutB->getPort(ID::A));
 | 
						|
					SigSpec lutB_output = sigmap(lutB->getPort(ID::Y)[0]);
 | 
						|
					int lutB_width = lutB->getParam(ID::WIDTH).as_int();
 | 
						|
					int lutB_arity = luts_arity[lutB];
 | 
						|
					pool<int> &lutB_dlogic_inputs = luts_dlogic_inputs[lutB];
 | 
						|
 | 
						|
					log_debug("Found %s.%s (cell A) feeding %s.%s (cell B).\n", log_id(module), log_id(lutA), log_id(module), log_id(lutB));
 | 
						|
 | 
						|
					if (index.query_is_output(lutA->getPort(ID::Y)))
 | 
						|
					{
 | 
						|
						log_debug("  Not combining LUTs (cascade connection feeds module output).\n");
 | 
						|
						continue;
 | 
						|
					}
 | 
						|
 | 
						|
					pool<SigBit> lutA_inputs;
 | 
						|
					pool<SigBit> lutB_inputs;
 | 
						|
					for (auto &bit : lutA_input)
 | 
						|
					{
 | 
						|
						if (bit.wire)
 | 
						|
							lutA_inputs.insert(sigmap(bit));
 | 
						|
					}
 | 
						|
					for (auto &bit : lutB_input)
 | 
						|
					{
 | 
						|
						if (bit.wire)
 | 
						|
							lutB_inputs.insert(sigmap(bit));
 | 
						|
					}
 | 
						|
 | 
						|
					pool<SigBit> common_inputs;
 | 
						|
					for (auto &bit : lutA_inputs)
 | 
						|
					{
 | 
						|
						if (lutB_inputs.count(bit))
 | 
						|
							common_inputs.insert(bit);
 | 
						|
					}
 | 
						|
 | 
						|
					int lutM_arity = lutA_arity + lutB_arity - 1 - common_inputs.size();
 | 
						|
					if (lutA_dlogic_inputs.size())
 | 
						|
						log_debug("  Cell A is a %d-LUT with %d dedicated connections. ", lutA_arity, GetSize(lutA_dlogic_inputs));
 | 
						|
					else
 | 
						|
						log_debug("  Cell A is a %d-LUT. ", lutA_arity);
 | 
						|
					if (lutB_dlogic_inputs.size())
 | 
						|
						log_debug("Cell B is a %d-LUT with %d dedicated connections.\n", lutB_arity, GetSize(lutB_dlogic_inputs));
 | 
						|
					else
 | 
						|
						log_debug("Cell B is a %d-LUT.\n", lutB_arity);
 | 
						|
					log_debug("  Cells share %d input(s) and can be merged into one %d-LUT.\n", GetSize(common_inputs), lutM_arity);
 | 
						|
 | 
						|
					const int COMBINE_A = 1, COMBINE_B = 2, COMBINE_EITHER = COMBINE_A | COMBINE_B;
 | 
						|
					int combine_mask = 0;
 | 
						|
					if (lutM_arity > lutA_width)
 | 
						|
						log_debug("  Not combining LUTs into cell A (combined LUT wider than cell A).\n");
 | 
						|
					else if (lutB_dlogic_inputs.size() > 0)
 | 
						|
						log_debug("  Not combining LUTs into cell A (cell B is connected to dedicated logic).\n");
 | 
						|
					else if (lutB->get_bool_attribute(ID::lut_keep))
 | 
						|
						log_debug("  Not combining LUTs into cell A (cell B has attribute \\lut_keep).\n");
 | 
						|
					else
 | 
						|
						combine_mask |= COMBINE_A;
 | 
						|
					if (lutM_arity > lutB_width)
 | 
						|
						log_debug("  Not combining LUTs into cell B (combined LUT wider than cell B).\n");
 | 
						|
					else if (lutA_dlogic_inputs.size() > 0)
 | 
						|
						log_debug("  Not combining LUTs into cell B (cell A is connected to dedicated logic).\n");
 | 
						|
					else if (lutA->get_bool_attribute(ID::lut_keep))
 | 
						|
						log_debug("  Not combining LUTs into cell B (cell A has attribute \\lut_keep).\n");
 | 
						|
					else
 | 
						|
						combine_mask |= COMBINE_B;
 | 
						|
 | 
						|
					int combine = combine_mask;
 | 
						|
					if (combine == COMBINE_EITHER)
 | 
						|
					{
 | 
						|
						log_debug("  Can combine into either cell.\n");
 | 
						|
						if (lutA_arity == 1)
 | 
						|
						{
 | 
						|
							log_debug("    Cell A is a buffer or inverter, combining into cell B.\n");
 | 
						|
							combine = COMBINE_B;
 | 
						|
						}
 | 
						|
						else if (lutB_arity == 1)
 | 
						|
						{
 | 
						|
							log_debug("    Cell B is a buffer or inverter, combining into cell A.\n");
 | 
						|
							combine = COMBINE_A;
 | 
						|
						}
 | 
						|
						else
 | 
						|
						{
 | 
						|
							log_debug("    Arbitrarily combining into cell A.\n");
 | 
						|
							combine = COMBINE_A;
 | 
						|
						}
 | 
						|
					}
 | 
						|
 | 
						|
					RTLIL::Cell *lutM, *lutR;
 | 
						|
					pool<SigBit> lutM_inputs, lutR_inputs;
 | 
						|
					pool<int> lutM_dlogic_inputs;
 | 
						|
					if (combine == COMBINE_A)
 | 
						|
					{
 | 
						|
						log_debug("  Combining LUTs into cell A.\n");
 | 
						|
						lutM = lutA;
 | 
						|
						lutM_inputs = lutA_inputs;
 | 
						|
						lutM_dlogic_inputs = lutA_dlogic_inputs;
 | 
						|
						lutR = lutB;
 | 
						|
						lutR_inputs = lutB_inputs;
 | 
						|
					}
 | 
						|
					else if (combine == COMBINE_B)
 | 
						|
					{
 | 
						|
						log_debug("  Combining LUTs into cell B.\n");
 | 
						|
						lutM = lutB;
 | 
						|
						lutM_inputs = lutB_inputs;
 | 
						|
						lutM_dlogic_inputs = lutB_dlogic_inputs;
 | 
						|
						lutR = lutA;
 | 
						|
						lutR_inputs = lutA_inputs;
 | 
						|
					}
 | 
						|
					else
 | 
						|
					{
 | 
						|
						log_debug("  Cannot combine LUTs.\n");
 | 
						|
						continue;
 | 
						|
					}
 | 
						|
 | 
						|
					pool<SigBit> lutR_unique;
 | 
						|
					for (auto &bit : lutR_inputs)
 | 
						|
					{
 | 
						|
						if (!common_inputs.count(bit) && bit != lutA_output)
 | 
						|
							lutR_unique.insert(bit);
 | 
						|
					}
 | 
						|
 | 
						|
					int lutM_width = lutM->getParam(ID::WIDTH).as_int();
 | 
						|
					SigSpec lutM_input = sigmap(lutM->getPort(ID::A));
 | 
						|
					std::vector<SigBit> lutM_new_inputs;
 | 
						|
					for (int i = 0; i < lutM_width; i++)
 | 
						|
					{
 | 
						|
						bool input_unused = false;
 | 
						|
						if (sigmap(lutM_input[i]) == lutA_output)
 | 
						|
							input_unused = true;
 | 
						|
						if (!lutM_input[i].wire && !lutM_dlogic_inputs.count(i))
 | 
						|
							input_unused = true;
 | 
						|
 | 
						|
						if (input_unused && lutR_unique.size())
 | 
						|
						{
 | 
						|
							SigBit new_input = lutR_unique.pop();
 | 
						|
							log_debug("    Connecting input %d as %s.\n", i, log_signal(new_input));
 | 
						|
							lutM_new_inputs.push_back(new_input);
 | 
						|
						}
 | 
						|
						else if (sigmap(lutM_input[i]) == lutA_output)
 | 
						|
						{
 | 
						|
							log_debug("    Disconnecting cascade input %d.\n", i);
 | 
						|
							lutM_new_inputs.push_back(SigBit());
 | 
						|
						}
 | 
						|
						else
 | 
						|
						{
 | 
						|
							log_debug("    Leaving input %d as %s.\n", i, log_signal(lutM_input[i]));
 | 
						|
							lutM_new_inputs.push_back(lutM_input[i]);
 | 
						|
						}
 | 
						|
					}
 | 
						|
					log_assert(lutR_unique.size() == 0);
 | 
						|
 | 
						|
					RTLIL::Const lutM_new_table(State::Sx, 1 << lutM_width);
 | 
						|
					for (int eval = 0; eval < 1 << lutM_width; eval++)
 | 
						|
					{
 | 
						|
						dict<SigBit, bool> eval_inputs;
 | 
						|
						for (size_t i = 0; i < lutM_new_inputs.size(); i++)
 | 
						|
						{
 | 
						|
							eval_inputs[lutM_new_inputs[i]] = (eval >> i) & 1;
 | 
						|
						}
 | 
						|
						eval_inputs[lutA_output] = evaluate_lut(lutA, eval_inputs);
 | 
						|
						lutM_new_table[eval] = (RTLIL::State) evaluate_lut(lutB, eval_inputs);
 | 
						|
					}
 | 
						|
 | 
						|
					log_debug("  Cell A truth table: %s.\n", lutA->getParam(ID::LUT).as_string().c_str());
 | 
						|
					log_debug("  Cell B truth table: %s.\n", lutB->getParam(ID::LUT).as_string().c_str());
 | 
						|
					log_debug("  Merged truth table: %s.\n", lutM_new_table.as_string().c_str());
 | 
						|
 | 
						|
					lutM->setParam(ID::LUT, lutM_new_table);
 | 
						|
					lutM->setPort(ID::A, lutM_new_inputs);
 | 
						|
					lutM->setPort(ID::Y, lutB_output);
 | 
						|
 | 
						|
					luts_arity[lutM] = lutM_arity;
 | 
						|
					luts.erase(lutR);
 | 
						|
					luts_arity.erase(lutR);
 | 
						|
 | 
						|
					worklist.insert(lutM);
 | 
						|
					worklist.erase(lutR);
 | 
						|
 | 
						|
					lutR->module->remove(lutR);
 | 
						|
 | 
						|
					combined_count++;
 | 
						|
					if (limit > 0)
 | 
						|
						limit--;
 | 
						|
				}
 | 
						|
			}
 | 
						|
		}
 | 
						|
		show_stats_by_arity();
 | 
						|
	}
 | 
						|
};
 | 
						|
 | 
						|
static void split(std::vector<std::string> &tokens, const std::string &text, char sep)
 | 
						|
{
 | 
						|
	size_t start = 0, end = 0;
 | 
						|
	while ((end = text.find(sep, start)) != std::string::npos) {
 | 
						|
		tokens.push_back(text.substr(start, end - start));
 | 
						|
		start = end + 1;
 | 
						|
	}
 | 
						|
	tokens.push_back(text.substr(start));
 | 
						|
}
 | 
						|
 | 
						|
struct OptLutPass : public Pass {
 | 
						|
	OptLutPass() : Pass("opt_lut", "optimize LUT cells") { }
 | 
						|
	void help() override
 | 
						|
	{
 | 
						|
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 | 
						|
		log("\n");
 | 
						|
		log("    opt_lut [options] [selection]\n");
 | 
						|
		log("\n");
 | 
						|
		log("This pass combines cascaded $lut cells with unused inputs.\n");
 | 
						|
		log("\n");
 | 
						|
		log("    -dlogic <type>:<cell-port>=<LUT-input>[:<cell-port>=<LUT-input>...]\n");
 | 
						|
		log("        preserve connections to dedicated logic cell <type> that has ports\n");
 | 
						|
		log("        <cell-port> connected to LUT inputs <LUT-input>. this includes\n");
 | 
						|
		log("        the case where both LUT and dedicated logic input are connected to\n");
 | 
						|
		log("        the same constant.\n");
 | 
						|
		log("\n");
 | 
						|
		log("    -limit N\n");
 | 
						|
		log("        only perform the first N combines, then stop. useful for debugging.\n");
 | 
						|
		log("\n");
 | 
						|
	}
 | 
						|
	void execute(std::vector<std::string> args, RTLIL::Design *design) override
 | 
						|
	{
 | 
						|
		log_header(design, "Executing OPT_LUT pass (optimize LUTs).\n");
 | 
						|
 | 
						|
		std::vector<dlogic_t> dlogic;
 | 
						|
		int limit = -1;
 | 
						|
 | 
						|
		size_t argidx;
 | 
						|
		for (argidx = 1; argidx < args.size(); argidx++)
 | 
						|
		{
 | 
						|
			if (args[argidx] == "-dlogic" && argidx+1 < args.size())
 | 
						|
			{
 | 
						|
				std::vector<std::string> tokens;
 | 
						|
				split(tokens, args[++argidx], ':');
 | 
						|
				if (tokens.size() < 2)
 | 
						|
					log_cmd_error("The -dlogic option requires at least one connection.\n");
 | 
						|
				dlogic_t entry;
 | 
						|
				entry.cell_type = "\\" + tokens[0];
 | 
						|
				for (auto it = tokens.begin() + 1; it != tokens.end(); ++it) {
 | 
						|
					std::vector<std::string> conn_tokens;
 | 
						|
					split(conn_tokens, *it, '=');
 | 
						|
					if (conn_tokens.size() != 2)
 | 
						|
						log_cmd_error("Invalid format of -dlogic signal mapping.\n");
 | 
						|
					IdString logic_port = "\\" + conn_tokens[0];
 | 
						|
					int lut_input = atoi(conn_tokens[1].c_str());
 | 
						|
					entry.lut_input_port[lut_input] = logic_port;
 | 
						|
				}
 | 
						|
				dlogic.push_back(entry);
 | 
						|
				continue;
 | 
						|
			}
 | 
						|
			if (args[argidx] == "-limit" && argidx + 1 < args.size())
 | 
						|
			{
 | 
						|
				limit = atoi(args[++argidx].c_str());
 | 
						|
				continue;
 | 
						|
			}
 | 
						|
			break;
 | 
						|
		}
 | 
						|
		extra_args(args, argidx, design);
 | 
						|
 | 
						|
		int eliminated_count = 0, combined_count = 0;
 | 
						|
		for (auto module : design->selected_modules())
 | 
						|
		{
 | 
						|
			OptLutWorker worker(dlogic, module, limit - eliminated_count - combined_count);
 | 
						|
			eliminated_count += worker.eliminated_count;
 | 
						|
			combined_count   += worker.combined_count;
 | 
						|
		}
 | 
						|
		if (eliminated_count)
 | 
						|
			design->scratchpad_set_bool("opt.did_something", true);
 | 
						|
		if (combined_count)
 | 
						|
			design->scratchpad_set_bool("opt.did_something", true);
 | 
						|
		log("\n");
 | 
						|
		log("Eliminated %d LUTs.\n", eliminated_count);
 | 
						|
		log("Combined %d LUTs.\n", combined_count);
 | 
						|
	}
 | 
						|
} OptLutPass;
 | 
						|
 | 
						|
PRIVATE_NAMESPACE_END
 |