Support import of $future_ff

frontends/verific/verific.cc

@@ -1142,6 +1142,11 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		module->connect(operatorOutput(inst),module->OriginalTag(new_verific_id(inst), tag, operatorInput(inst)));
 		return true;
 	}
+	if (inst->Type() == OPER_YOSYSHQ_FUTURE_FF)
+	{
+		module->connect(operatorOutput(inst),module->FutureFF(new_verific_id(inst), operatorInput(inst)));
+		return true;
+	}
 
 	#undef IN
 	#undef IN1

kernel/celltypes.h

@@ -106,6 +106,7 @@ struct CellTypes
 		setup_type(ID($get_tag), {ID::A}, {ID::Y});
 		setup_type(ID($overwrite_tag), {ID::A, ID::SET, ID::CLR}, pool<RTLIL::IdString>());
 		setup_type(ID($original_tag), {ID::A}, {ID::Y});
+		setup_type(ID($future_ff), {ID::A}, {ID::Y});
 	}
 
 	void setup_internals_eval()

kernel/rtlil.cc

@@ -1855,6 +1855,13 @@ namespace {
 				check_expected();
 				return;
 			}
+			if (cell->type.in(ID($future_ff))) {
+				param(ID::WIDTH);
+				port(ID::A, param(ID::WIDTH));
+				port(ID::Y, param(ID::WIDTH));
+				check_expected();
+				return;
+			}
 			error(__LINE__);
 		}
 	};
@@ -3323,6 +3330,17 @@ RTLIL::SigSpec RTLIL::Module::OriginalTag(RTLIL::IdString name, const std::strin
 	return sig;
 }
 
+RTLIL::SigSpec RTLIL::Module::FutureFF(RTLIL::IdString name, const RTLIL::SigSpec &sig_e, const std::string &src)
+{
+	RTLIL::SigSpec sig = addWire(NEW_ID, sig_e.size());
+	Cell *cell = addCell(name, ID($future_ff));
+	cell->parameters[ID::WIDTH] = sig_e.size();
+	cell->setPort(ID::A, sig_e);
+	cell->setPort(ID::Y, sig);
+	cell->set_src_attribute(src);
+	return sig;
+}
+
 RTLIL::Wire::Wire()
 {
 	static unsigned int hashidx_count = 123456789;

kernel/rtlil.h

@@ -1469,6 +1469,7 @@ public:
 	RTLIL::SigSpec GetTag          (RTLIL::IdString name, const std::string &tag, const RTLIL::SigSpec &sig_e, const std::string &src = "");
 	RTLIL::Cell*   addOverwriteTag (RTLIL::IdString name, const std::string &tag, const RTLIL::SigSpec &sig_e, const RTLIL::SigSpec &sig_s, const RTLIL::SigSpec &sig_c, const std::string &src = "");
 	RTLIL::SigSpec OriginalTag     (RTLIL::IdString name, const std::string &tag, const RTLIL::SigSpec &sig_e, const std::string &src = "");
+	RTLIL::SigSpec FutureFF        (RTLIL::IdString name, const RTLIL::SigSpec &sig_e, const std::string &src = "");
 
 #ifdef WITH_PYTHON
 	static std::map<unsigned int, RTLIL::Module*> *get_all_modules(void);

techlibs/common/simlib.v

@@ -2728,3 +2728,16 @@ assign Y = A;
 endmodule
 
 // --------------------------------------------------------
+
+module \$future_ff (A, Y);
+
+parameter WIDTH = 0;
+
+input [WIDTH-1:0] A;
+output [WIDTH-1:0] Y;
+
+assign Y = A;
+
+endmodule
+
+// --------------------------------------------------------