Use $__ABC_FF_ instead of $_FF_

backends/aiger/xaiger.cc

@@ -222,8 +222,8 @@ struct XAigerWriter
 
 			log_assert(!holes_mode);
 
-			// FIXME: Should short here, rather than provide $_DFF_[NP]_
+			// FIXME: Should short here, rather than provide $__ABC_FF_
-			//        to ABC as a user cell
+			//        to ABC like a user cell
 			//if (cell->type.in("$_FF_" /*, "$_DFF_N_", "$_DFF_P_"*/))
 			//{
 			//	SigBit D = sigmap(cell->getPort("\\D").as_bit());

passes/techmap/abc9.cc

@@ -399,6 +399,9 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		//log("Extracted %d gates and %d wires to a netlist network with %d inputs and %d outputs.\n",
 		//		count_gates, GetSize(signal_list), count_input, count_output);
 
+#if 0
+		Pass::call(design, stringf("write_verilog -noexpr -norename %s/before.xaig", tempdir_name.c_str()));
+#endif
 		Pass::call(design, stringf("write_xaiger -map %s/input.sym %s/input.xaig", tempdir_name.c_str(), tempdir_name.c_str()));
 
 		std::string buffer;
@@ -513,26 +516,23 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		// in preparation for stitching mapped_mod in
 		// Short $_FF_ cells used by ABC (FIXME)
 		dict<IdString, decltype(RTLIL::Cell::parameters)> erased_boxes;
+		std::vector<RTLIL::Cell*> abc_dff;
 		for (auto it = module->cells_.begin(); it != module->cells_.end(); ) {
 			RTLIL::Cell* cell = it->second;
 			if (cell->type.in("$_AND_", "$_NOT_")) {
 				it = module->cells_.erase(it);
 				continue;
 			}
-			else if (cell->type.in("$_FF_")) {
+			if (cell->type.in("$__ABC_FF_"))
-				RTLIL::Wire *D = cell->getPort("\\D").as_wire();
+				abc_dff.emplace_back(cell);
-				RTLIL::Wire *Q = cell->getPort("\\Q").as_wire();
+			else {
-				Q->attributes.swap(D->attributes);
-				module->connect(Q, D);
-				it = module->cells_.erase(it);
-				continue;
-			}
 				RTLIL::Module* box_module = design->module(cell->type);
 				if (box_module && box_module->attributes.count("\\abc_box_id")) {
 					erased_boxes.insert(std::make_pair(it->first, std::move(cell->parameters)));
 					it = module->cells_.erase(it);
 					continue;
 				}
+			}
 			++it;
 		}
 		// Do the same for module connections
@@ -671,6 +671,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		int in_wires = 0, out_wires = 0;
 
 		// Stitch in mapped_mod's inputs/outputs into module
+		// TODO: iterate using ports
 		for (auto &it : mapped_mod->wires_) {
 			RTLIL::Wire *w = it.second;
 			if (!w->port_input && !w->port_output)
@@ -697,6 +698,13 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 			}
 		}
 
+		for (auto cell : abc_dff) {
+			RTLIL::SigBit D = cell->getPort("\\D");
+			RTLIL::SigBit Q = cell->getPort("\\Q");
+			module->connect(Q, D);
+			module->remove(cell);
+		}
+
 		//log("ABC RESULTS:        internal signals: %8d\n", int(signal_list.size()) - in_wires - out_wires);
 		log("ABC RESULTS:           input signals: %8d\n", in_wires);
 		log("ABC RESULTS:          output signals: %8d\n", out_wires);

techlibs/xilinx/ff_map.v

@@ -29,12 +29,20 @@ module  \$_DFF_P_   (input D, C, output Q);
 `else
     wire Q_next;
 	\$__ABC_FDRE #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q_next), .Q_past(Q), .C(C), .CE(1'b1), .R(1'b0));
-	\$_FF_ abc_dff (.D(Q_next), .Q(Q));
+	\$__ABC_FF_ abc_dff (.D(Q_next), .Q(Q));
 `endif
 endmodule
 
 module  \$_DFFE_NP_ (input D, C, E, output Q); FDRE_1 #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E),    .R(1'b0)); endmodule
-module  \$_DFFE_PP_ (input D, C, E, output Q); FDRE   #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E),    .R(1'b0)); endmodule
+module  \$_DFFE_PP_ (input D, C, E, output Q);
+`ifndef _ABC
+	FDRE   #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E),    .R(1'b0));
+`else
+	wire Q_next;
+	\$__ABC_FDRE #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q_next), .Q_past(Q), .C(C), .CE(E), .R(1'b0));
+	\$__ABC_FF_ abc_dff (.D(Q_next), .Q(Q));
+`endif
+endmodule
 
 module  \$_DFF_NN0_ (input D, C, R, output Q); FDCE_1 #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR(!R)); endmodule
 module  \$_DFF_NP0_ (input D, C, R, output Q); FDCE_1 #(.INIT(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR( R)); endmodule