pattern reduce

state <IdString> portname
udata <vector<pair<Cell*, IdString>>> chain longest_chain
udata <pool<Cell*>> non_first_cells
udata <SigSpec> leaves

code
	non_first_cells.clear();
	subpattern(setup);
endcode

match first
	select first->type.in($_AND_, $_OR_, $_XOR_)
	filter !non_first_cells.count(first)
generate
	SigSpec A = module->addWire(NEW_ID);
	SigSpec B = module->addWire(NEW_ID);
	SigSpec Y = module->addWire(NEW_ID);
	switch (rng(3))
	{
	case 0:
		module->addAndGate(NEW_ID, A, B, Y);
		break;
	case 1:
		module->addOrGate(NEW_ID, A, B, Y);
		break;
	case 2:
		module->addXorGate(NEW_ID, A, B, Y);
		break;
	}
endmatch

code
	leaves = SigSpec();
	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());
	if (GetSize(longest_chain) > 1)
		accept;
endcode

// ------------------------------------------------------------------

subpattern setup

match first
	select first->type.in($_AND_, $_OR_, $_XOR_)
endmatch

code portname
	portname = \A;
	branch;
	portname = \B;
endcode

match next
	select next->type.in($_AND_, $_OR_, $_XOR_)
	select nusers(port(next, \Y)) == 2
	index <IdString> next->type === first->type
	index <SigSpec> port(next, \Y) === port(first, portname)
endmatch

code
	non_first_cells.insert(next);
endcode

// ------------------------------------------------------------------

subpattern tail
arg first

match next
	semioptional
	select next->type.in($_AND_, $_OR_, $_XOR_)
	select nusers(port(next, \Y)) == 2
	index <IdString> next->type === chain.back().first->type
	index <SigSpec> port(next, \Y) === port(chain.back().first, chain.back().second)
generate 10
	SigSpec A = module->addWire(NEW_ID);
	SigSpec B = module->addWire(NEW_ID);
	SigSpec Y = port(chain.back().first, chain.back().second);
	Cell *c = module->addAndGate(NEW_ID, A, B, Y);
	c->type = chain.back().first->type;
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;
		leaves.append(port(chain.back().first, chain.back().second));
	}
finally
	if (next)
		chain.pop_back();
endcode

// ==================================================================

pattern eqpmux

state <bool> eq_ne_signed
state <SigSpec> eq_inA eq_inB
state <int> pmux_slice_eq pmux_slice_ne

match eq
	select eq->type == $eq
	choice <IdString> AB {\A, \B}
	define <IdString> BA AB == \A ? \B : \A
	set eq_inA port(eq, \A)
	set eq_inB port(eq, \B)
	set eq_ne_signed param(eq, \A_SIGNED).as_bool()
generate 100 10
	SigSpec A = module->addWire(NEW_ID, rng(7)+1);
	SigSpec B = module->addWire(NEW_ID, rng(7)+1);
	SigSpec Y = module->addWire(NEW_ID);
	module->addEq(NEW_ID, A, B, Y, rng(2));
endmatch

match pmux
	select pmux->type == $pmux
	slice idx GetSize(port(pmux, \S))
	index <SigBit> port(pmux, \S)[idx] === port(eq, \Y)
	set pmux_slice_eq idx
generate 100 10
	int width = rng(7) + 1;
	int numsel = rng(4) + 1;
	int idx = rng(numsel);

	SigSpec A = module->addWire(NEW_ID, width);
	SigSpec Y = module->addWire(NEW_ID, width);

	SigSpec B, S;
	for (int i = 0; i < numsel; i++) {
		B.append(module->addWire(NEW_ID, width));
		S.append(i == idx ? port(eq, \Y) : module->addWire(NEW_ID));
	}

	module->addPmux(NEW_ID, A, B, S, Y);
endmatch

match ne
	select ne->type == $ne
	choice <IdString> AB {\A, \B}
	define <IdString> BA (AB == \A ? \B : \A)
	index <SigSpec> port(ne, AB) === eq_inA
	index <SigSpec> port(ne, BA) === eq_inB
	index <int> param(ne, \A_SIGNED).as_bool() === eq_ne_signed
generate 100 10
	SigSpec A = eq_inA, B = eq_inB, Y;
	if (rng(2)) {
		std::swap(A, B);
	}
	if (rng(2)) {
		for (auto bit : port(pmux, \S)) {
			if (nusers(bit) < 2)
				Y.append(bit);
		}
		if (GetSize(Y))
			Y = Y[rng(GetSize(Y))];
		else
			Y = module->addWire(NEW_ID);
	} else {
		Y = module->addWire(NEW_ID);
	}
	module->addNe(NEW_ID, A, B, Y, rng(2));
endmatch

match pmux2
	select pmux2->type == $pmux
	slice idx GetSize(port(pmux2, \S))
	index <Cell*> pmux2 === pmux
	index <SigBit> port(pmux2, \S)[idx] === port(ne, \Y)
	set pmux_slice_ne idx
endmatch

code
	accept;
endcode