diff --git a/search/CheckCapacitanceLimits.cc b/search/CheckCapacitanceLimits.cc
index c4d2c021..ced71a7d 100644
--- a/search/CheckCapacitanceLimits.cc
+++ b/search/CheckCapacitanceLimits.cc
@@ -26,6 +26,8 @@
 #include "Corner.hh"
 #include "PortDirection.hh"
 #include "Sim.hh"
+#include "Graph.hh"
+#include "GraphDelayCalc.hh"
 
 namespace sta {
 
@@ -316,9 +318,13 @@ CheckCapacitanceLimits::checkPin(const Pin *pin)
   const Network *network = sta_->network();
   const Sim *sim = sta_->sim();
   const Sdc *sdc = sta_->sdc();
+  const Graph *graph = sta_->graph();
+  GraphDelayCalc *dcalc = sta_->graphDelayCalc();
+  Vertex *vertex = graph->pinLoadVertex(pin);
   return network->direction(pin)->isAnyOutput()
     && !sim->logicZeroOne(pin)
-    && !sdc->isDisabled(pin);
+    && !sdc->isDisabled(pin)
+    && !(vertex && sta_->graphDelayCalc()->isIdealClk(vertex));
 }
 
 } // namespace
diff --git a/search/CheckFanoutLimits.cc b/search/CheckFanoutLimits.cc
index 4ca89ca8..352482f2 100644
--- a/search/CheckFanoutLimits.cc
+++ b/search/CheckFanoutLimits.cc
@@ -22,6 +22,8 @@
 #include "Sdc.hh"
 #include "Sim.hh"
 #include "PortDirection.hh"
+#include "Graph.hh"
+#include "GraphDelayCalc.hh"
 
 namespace sta {
 
@@ -285,9 +287,13 @@ CheckFanoutLimits::checkPin(const Pin *pin)
   const Network *network = sta_->network();
   const Sim *sim = sta_->sim();
   const Sdc *sdc = sta_->sdc();
+  const Graph *graph = sta_->graph();
+  GraphDelayCalc *dcalc = sta_->graphDelayCalc();
+  Vertex *vertex = graph->pinLoadVertex(pin);
   return network->direction(pin)->isAnyOutput()
     && !sim->logicZeroOne(pin)
-    && !sdc->isDisabled(pin);
+    && !sdc->isDisabled(pin)
+    && !(vertex && dcalc->isIdealClk(vertex));
 }
 
 } // namespace
diff --git a/search/Sta.cc b/search/Sta.cc
index 984891be..42e42b14 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -4817,7 +4817,7 @@ Sta::slowDrvrIterator()
   return new SlowDrvrIterator(insts);
 }
 
-////////////////////////////////////////////////////////////////'
+////////////////////////////////////////////////////////////////
 
 void
 Sta::checkSlewLimitPreamble()
@@ -4907,8 +4907,8 @@ Sta::checkFanoutLimitPreamble()
 {
   if (check_fanout_limits_ == nullptr)
     makeCheckFanoutLimits();
-  // Sim values required to suppress reporting constant nets.
-  ensureLevelized();
+  // For sim values and ideal clocks.
+  findDelays();
 }
 
 Pin *
@@ -4974,8 +4974,8 @@ Sta::checkCapacitanceLimitPreamble()
 {
   if (check_capacitance_limits_ == nullptr)
     makeCheckCapacitanceLimits();
-  // Sim values required to suppress reporting constant nets.
-  ensureLevelized();
+  // For sim values and ideal clocks.
+  findDelays();
 }
 
 Pin *