Use default parameter value in getParam

Fixes #1822.

2 files changed, 13 insertions, 4 deletions

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 0e9347267..2aefe30b1 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -2619,7 +2619,16 @@ void RTLIL::Cell::setParam(RTLIL::IdString paramname, RTLIL::Const value)
 
 const RTLIL::Const &RTLIL::Cell::getParam(RTLIL::IdString paramname) const
 {
-	return parameters.at(paramname);
+	static const RTLIL::Const empty;
+	const auto &it = parameters.find(paramname);
+	if (it != parameters.end())
+		return it->second;
+	if (module && module->design) {
+		RTLIL::Module *m = module->design->module(type);
+		if (m)
+			return m->parameter_default_values.at(paramname, empty);
+	}
+	return empty;
 }
 
 void RTLIL::Cell::sort()
diff --git a/techlibs/xilinx/xilinx_dffopt.cc b/techlibs/xilinx/xilinx_dffopt.cc
index ac9b57fe1..c608db883 100644
--- a/techlibs/xilinx/xilinx_dffopt.cc
+++ b/techlibs/xilinx/xilinx_dffopt.cc
@@ -209,7 +209,7 @@ lut_sigin_done:
 					continue;
 				LutData lut_d = it_D->second.first;
 				Cell *cell_d = it_D->second.second;
-				if (cell->hasParam(ID(IS_D_INVERTED)) && cell->getParam(ID(IS_D_INVERTED)).as_bool()) {
+				if (cell->getParam(ID(IS_D_INVERTED)).as_bool()) {
 					// Flip all bits in the LUT.
 					for (int i = 0; i < GetSize(lut_d.first); i++)
 						lut_d.first.bits[i] = (lut_d.first.bits[i] == State::S1) ? State::S0 : State::S1;
@@ -249,7 +249,7 @@ lut_sigin_done:
 				if (has_s) {
 					SigBit sig_S = sigmap(cell->getPort(ID::S));
 					LutData lut_s = LutData(Const(2, 2), {sig_S});
-					bool inv_s = cell->hasParam(ID(IS_S_INVERTED)) && cell->getParam(ID(IS_S_INVERTED)).as_bool();
+					bool inv_s = cell->getParam(ID(IS_S_INVERTED)).as_bool();
 					auto it_S = bit_to_lut.find(sig_S);
 					if (it_S != bit_to_lut.end())
 						lut_s = it_S->second.first;
@@ -271,7 +271,7 @@ lut_sigin_done:
 				if (has_r) {
 					SigBit sig_R = sigmap(cell->getPort(ID::R));
 					LutData lut_r = LutData(Const(2, 2), {sig_R});
-					bool inv_r = cell->hasParam(ID(IS_R_INVERTED)) && cell->getParam(ID(IS_R_INVERTED)).as_bool();
+					bool inv_r = cell->getParam(ID(IS_R_INVERTED)).as_bool();
 					auto it_R = bit_to_lut.find(sig_R);
 					if (it_R != bit_to_lut.end())
 						lut_r = it_R->second.first;