wireload for fanout=0 NaN

dcalc/DmpDelayCalc.cc

@@ -244,7 +244,8 @@ DmpCeffTwoPoleDelayCalc::findParasitic(const Pin *drvr_pin,
 						parasitic_ap);
       // Estimated parasitics are not recorded in the "database", so
       // it for deletion after the drvr pin delay calc is finished.
-      unsaved_parasitics_.push_back(parasitic);
+      if (parasitic)
+	unsaved_parasitics_.push_back(parasitic);
       return parasitic;
     }
   }

dcalc/LumpedCapDelayCalc.cc

@@ -90,7 +90,8 @@ LumpedCapDelayCalc::findParasitic(const Pin *drvr_pin,
 						parasitic_ap);
       // Estimated parasitics are not recorded in the "database", so
       // it for deletion after the drvr pin delay calc is finished.
-      unsaved_parasitics_.push_back(parasitic);
+      if (parasitic)
+	unsaved_parasitics_.push_back(parasitic);
       return parasitic;
     }
   }

parasitics/ConcreteParasitics.cc

@@ -1670,10 +1670,13 @@ ConcreteParasitics::estimatePiElmore(const Pin *drvr_pin,
 		   c2, rpi, c1,
 		   elmore_res, elmore_cap, elmore_use_load_cap);
 
-  return new ConcretePiElmoreEstimated(c2, rpi, c1, elmore_res, elmore_cap,
-				       elmore_use_load_cap,
-				       rf, op_cond, corner, min_max,
-				       sdc_);
+  if (c1 > 0.0 || c2 > 0.0)
+    return new ConcretePiElmoreEstimated(c2, rpi, c1, elmore_res, elmore_cap,
+					 elmore_use_load_cap,
+					 rf, op_cond, corner, min_max,
+					 sdc_);
+  else
+    return nullptr;
 }
 
 ////////////////////////////////////////////////////////////////

parasitics/EstimateParasitics.cc

@@ -150,7 +150,8 @@ EstimateParasitics::estimatePiElmoreBalanced(const Pin *drvr_pin,
 					     float &elmore_cap,
 					     bool &elmore_use_load_cap)
 {
-  if (wireload_res == 0.0) {
+  if (wireload_res == 0.0
+      || fanout == 0) {
     // No resistance, so load is capacitance only.
     c2 = wireload_cap + net_pin_cap;
     rpi = 0.0;