From a09d9f0a5177d3e67421cc1456b125b7ee7d084a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik@cutebit.org>
Date: Mon, 4 Nov 2024 11:07:09 +0100
Subject: [PATCH] Add warning for poor activities convergence

---
 doc/messages.txt |  1 +
 power/Power.cc   | 38 ++++++++++++++++++++++----------------
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/doc/messages.txt b/doc/messages.txt
index 97d1a06a..c2158782 100644
--- a/doc/messages.txt
+++ b/doc/messages.txt
@@ -300,6 +300,7 @@
 1060 Genclks.cc:275            no master clock found for generated clock %s.
 1062 Genclks.cc:939            generated clock %s source pin %s missing paths from master clock %s.
 1100 Power.cc:556              unknown cudd constant
+1101 Power.cc:651              poor convergence of propagated activities for power estimation after %d passes
 1110 Liberty.cc:763            cell %s/%s port %s not found in cell %s/%s.
 1111 Liberty.cc:789            cell %s/%s %s -> %s timing group %s not found in cell %s/%s.
 1112 Liberty.cc:808            Liberty cell %s/%s for corner %s/%s not found.
diff --git a/power/Power.cc b/power/Power.cc
index f68c903c..7a0f9677 100644
--- a/power/Power.cc
+++ b/power/Power.cc
@@ -629,22 +629,28 @@ Power::ensureActivities()
       bfs.visit(levelize_->maxLevel(), &visitor);
       // Propagate activiities through registers.
       InstanceSet regs = std::move(visitor.visitedRegs());
-      int pass = 1;
-      while (!regs.empty() && pass < max_activity_passes_) {
-        visitor.init();
-        InstanceSet::Iterator reg_iter(regs);
-	while (reg_iter.hasNext()) {
-	  const Instance *reg = reg_iter.next();
-	  // Propagate activiities across register D->Q.
-	  seedRegOutputActivities(reg, bfs);
-	}
-	// Propagate register output activities through
-	// combinational logic.
-	bfs.visit(levelize_->maxLevel(), &visitor);
-        regs = std::move(visitor.visitedRegs());
-        debugPrint(debug_, "power_activity", 1, "Pass %d change %.2f",
-                   pass, visitor.maxChange());
-        pass++;
+      if (!regs.empty()) {
+        int pass = 1;
+        while (!regs.empty() && pass < max_activity_passes_) {
+          visitor.init();
+          InstanceSet::Iterator reg_iter(regs);
+          while (reg_iter.hasNext()) {
+            const Instance *reg = reg_iter.next();
+            // Propagate activiities across register D->Q.
+            seedRegOutputActivities(reg, bfs);
+          }
+          // Propagate register output activities through
+          // combinational logic.
+          bfs.visit(levelize_->maxLevel(), &visitor);
+          regs = std::move(visitor.visitedRegs());
+          debugPrint(debug_, "power_activity", 1, "Pass %d change %.2f",
+                     pass, visitor.maxChange());
+          pass++;
+        }
+        if (visitor.maxChange() > 0.20) {
+          report_->warn(1101, "poor convergence of propagated activities for power estimation after %d passes",
+                        max_activity_passes_);
+        }
       }
       activities_valid_ = true;
     }