issue1879 overlapping path delay exceptions

Signed-off-by: James Cherry <cherry@parallaxsw.com>

include/sta/ExceptionPath.hh

@@ -439,6 +439,9 @@ public:
   bool matches(const Pin *pin,
 	       const RiseFall *end_rf) const;
   bool matches(const Clock *clk) const;
+  bool matches(const Pin *pin,
+               const RiseFall *end_rf,
+               const Network *network) const;
   bool matchesFilter(const Pin *pin,
 		     const ClockEdge *clk_edge,
 		     const RiseFall *end_rf,

include/sta/Sdc.hh

@@ -976,6 +976,10 @@ public:
 		    const MinMax *min_max,
 		    bool match_min_max_exactly,
 		    bool require_to_pin) const;
+  bool isCompleteTo(ExceptionState *state,
+                    const Pin *pin,
+                    const RiseFall *rf,
+                    const MinMax *min_max) const;
   bool isPathDelayInternalStartpoint(const Pin *pin) const;
   PinSet *pathDelayInternalStartpoints() const;
   bool isPathDelayInternalEndpoint(const Pin *pin) const;

sdc/ExceptionPath.cc

@@ -1465,6 +1465,23 @@ ExceptionTo::matches(const Pin *pin,
 	&& end_rf_->matches(end_rf));
 }
 
+bool
+ExceptionTo::matches(const Pin *pin,
+ 		     const RiseFall *end_rf,
+		     const Network *network) const
+{
+  return (pins_
+	  && pins_->hasKey(const_cast<Pin*>(pin))
+	  && rf_->matches(end_rf)
+	  && end_rf_->matches(end_rf))
+    || (insts_
+	&& insts_->hasKey(network->instance(pin))
+	&& (network->direction(pin)->isAnyInput()
+            || network->direction(pin)->isInternal())
+	&& rf_->matches(end_rf)
+	&& end_rf_->matches(end_rf));
+}
+
 bool
 ExceptionTo::matches(const Pin *pin,
 		     const RiseFall *end_rf) const

sdc/Sdc.cc

@@ -5620,6 +5620,20 @@ Sdc::isCompleteTo(ExceptionState *state,
 			  min_max, match_min_max_exactly, require_to_pin);
 }
 
+bool
+Sdc::isCompleteTo(ExceptionState *state,
+		  const Pin *pin,
+		  const RiseFall *rf,
+		  const MinMax *min_max) const
+{
+  ExceptionPath *exception = state->exception();
+  ExceptionTo *to = exception->to();
+  return state->nextThru() == nullptr
+    && to
+    && exception->matches(min_max, true)
+    && to->matches(pin, rf, network_);
+}
+
 ////////////////////////////////////////////////////////////////
 
 Wireload *

search/Search.cc

@@ -1134,11 +1134,9 @@ ArrivalVisitor::visit(Vertex *vertex)
 	  && network->isLatchData(pin))
 	search->enqueueLatchDataOutputs(vertex);
     }
-    if ((!search->arrivalsAtEndpointsExist()
+    if (!search->arrivalsAtEndpointsExist()
         || always_to_endpoints_
         || arrivals_changed)
-	&& (network->isRegClkPin(pin)
-	    || !sdc->isPathDelayInternalEndpoint(pin)))
       search->arrivalIterator()->enqueueAdjacentVertices(vertex, adj_pred_);
     if (arrivals_changed) {
       debugPrint(debug, "search", 4, "arrival changed");
@@ -2033,10 +2031,6 @@ PathVisitor::visitEdge(const Pin *from_pin,
     VertexPathIterator from_iter(from_vertex, search);
     while (from_iter.hasNext()) {
       PathVertex *from_path = from_iter.next();
-      Tag *from_tag = from_path->tag(sta_);
-      // Only propagate seeded paths from segment startpoint.
-      if (!search->isSegmentStart(from_pin)
-	  || from_tag->isSegmentStart()) {
       PathAnalysisPt *path_ap = from_path->pathAnalysisPt(sta_);
       const MinMax *min_max = path_ap->pathMinMax();
       const RiseFall *from_rf = from_path->transition(sta_);
@@ -2056,7 +2050,6 @@ PathVisitor::visitEdge(const Pin *from_pin,
       }
     }
   }
-  }
   return true;
 }
 
@@ -2565,6 +2558,10 @@ Search::mutateTag(Tag *from_tag,
 	// Don't propagate a completed false path -thru unless it is a
 	// clock (which ignores exceptions).
 	return nullptr;
+      // Don't propagate path delay tags past the -to pin.
+      if (exception->isPathDelay()
+          && sdc_->isCompleteTo(state, from_pin, from_rf, min_max))
+        return nullptr;
       if (state->matchesNextThru(from_pin,to_pin,to_rf,min_max,network_)) {
 	// Found a -thru that we've been waiting for.
 	if (state->nextState()->isComplete()