rtlil: publish signorm fanout

kernel/rtlil.h

@@ -2144,6 +2144,7 @@ public:
 	int next_timestamp();
 	std::vector<Cell *> dirty_cells(int starting_from);
 	const pool<PortBit> &fanout(SigBit bit);
+	const dict<SigBit, pool<PortBit>> &signorm_fanout() const;
 
 	template<typename T> void rewrite_sigspecs(T &functor);
 	template<typename T> void rewrite_sigspecs2(T &functor);

kernel/rtlil_bufnorm.cc

@@ -498,6 +498,11 @@ const pool<RTLIL::PortBit> &RTLIL::Module::fanout(SigBit bit) {
 	return found->second;
 }
 
+const dict<RTLIL::SigBit, pool<RTLIL::PortBit>> &RTLIL::Module::signorm_fanout() const {
+	log_assert(sig_norm_index != nullptr);
+	return sig_norm_index->fanout;
+}
+
 void RTLIL::Module::remove(RTLIL::Cell *cell)
 {
 	while (!cell->connections_.empty())