Add demo_reduce pass to demonstrace recursive pattern matching

Signed-off-by: Clifford Wolf <clifford@clifford.at>

passes/pmgen/.gitignore

@@ -1,2 +1,3 @@
+/demo_reduce_pm.h
 /ice40_dsp_pm.h
 /peepopt_pm.h

passes/pmgen/Makefile.inc

@@ -9,6 +9,12 @@ $(eval $(call add_extra_objs,passes/pmgen/ice40_dsp_pm.h))
 
 # --------------------------------------
 
+OBJS += passes/pmgen/demo_reduce.o
+passes/pmgen/demo_reduce.o: passes/pmgen/demo_reduce_pm.h
+$(eval $(call add_extra_objs,passes/pmgen/demo_reduce_pm.h))
+
+# --------------------------------------
+
 OBJS += passes/pmgen/peepopt.o
 passes/pmgen/peepopt.o: passes/pmgen/peepopt_pm.h
 $(eval $(call add_extra_objs,passes/pmgen/peepopt_pm.h))

passes/pmgen/demo_reduce.cc

@@ -0,0 +1,99 @@
+/*
+ *  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/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+#include "passes/pmgen/demo_reduce_pm.h"
+
+void create_reduce(demo_reduce_pm &pm)
+{
+	auto &st = pm.st_reduce;
+	auto &ud = pm.ud_reduce;
+
+	if (ud.longest_chain.empty())
+		return;
+
+	log("Found chain of length %d (%s):\n", GetSize(ud.longest_chain), log_id(st.first->type));
+
+	SigSpec A;
+	SigSpec Y = ud.longest_chain.front().first->getPort(ID(Y));
+	auto last_cell = ud.longest_chain.back().first;
+
+	for (auto it : ud.longest_chain) {
+		auto cell = it.first;
+		if (cell == last_cell) {
+			A.append(cell->getPort(ID(A)));
+			A.append(cell->getPort(ID(B)));
+		} else {
+			A.append(cell->getPort(it.second == ID(A) ? ID(B) : ID(A)));
+		}
+		log("    %s\n", log_id(cell));
+		pm.autoremove(cell);
+	}
+
+	Cell *c;
+
+	if (last_cell->type == ID($_AND_))
+		c = pm.module->addReduceAnd(NEW_ID, A, Y);
+	else if (last_cell->type == ID($_OR_))
+		c = pm.module->addReduceOr(NEW_ID, A, Y);
+	else if (last_cell->type == ID($_XOR_))
+		c = pm.module->addReduceXor(NEW_ID, A, Y);
+	else
+		log_abort();
+
+	log("    -> %s (%s)\n", log_id(c), log_id(c->type));
+}
+
+struct DemoReducePass : public Pass {
+	DemoReducePass() : Pass("demo_reduce", "map chains of AND/OR/XOR") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    demo_reduce [options] [selection]\n");
+		log("\n");
+		log("Demo for recursive pmgen patterns. Map chains of AND/OR/XOR to $reduce_*.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing DEMO_REDUCE pass.\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			// if (args[argidx] == "-singleton") {
+			// 	singleton_mode = true;
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+			demo_reduce_pm(module, module->selected_cells()).run_reduce(create_reduce);
+	}
+} DemoReducePass;
+
+PRIVATE_NAMESPACE_END

passes/pmgen/demo_reduce.pmg

@@ -0,0 +1,81 @@
+pattern reduce
+
+state <IdString> portname
+udata <vector<pair<Cell*, IdString>>> chain longest_chain
+udata <pool<Cell*>> non_first_cells
+
+code
+	non_first_cells.clear();
+	subpattern(setup);
+endcode
+
+match first
+	select first->type.in($_AND_, $_OR_, $_XOR_)
+	filter !non_first_cells.count(first)
+endmatch
+
+code
+	longest_chain.clear();
+	chain.push_back(make_pair(first, \A));
+	subpattern(tail);
+	chain.back().second = \B;
+	subpattern(tail);
+finally
+	chain.pop_back();
+	log_assert(chain.empty());
+endcode
+
+// ------------------------------------------------------------------
+
+subpattern setup
+
+match first
+	select first->type.in($_AND_, $_OR_, $_XOR_)
+endmatch
+
+code portname
+	portname = \A;
+	branch;
+	portname = \B;
+endcode
+
+match next
+	select nusers(port(next, \Y)) == 2
+	select next->type.in($_AND_, $_OR_, $_XOR_)
+	index <IdString> next->type === first->type
+	index <SigSpec> port(next, \Y) === port(first, portname)
+endmatch
+
+code
+	non_first_cells.insert(next);
+	reject;
+endcode
+
+// ------------------------------------------------------------------
+
+subpattern tail
+arg first
+
+match next
+	semioptional
+	select nusers(port(next, \Y)) == 2
+	select next->type.in($_AND_, $_OR_, $_XOR_)
+	index <IdString> next->type === chain.back().first->type
+	index <SigSpec> port(next, \Y) === port(chain.back().first, chain.back().second)
+endmatch
+
+code
+	if (next) {
+		chain.push_back(make_pair(next, \A));
+		subpattern(tail);
+		chain.back().second = \B;
+		subpattern(tail);
+	} else {
+		if (GetSize(chain) > GetSize(longest_chain))
+			longest_chain = chain;
+	}
+	reject;
+finally
+	if (next)
+		chain.pop_back();
+endcode