diff --git a/FuzzerDriver.cpp b/FuzzerDriver.cpp
index 434c481..9f1621f 100644
--- a/FuzzerDriver.cpp
+++ b/FuzzerDriver.cpp
@@ -483,9 +483,9 @@
 
   std::string CFPath = CFPathOrNull ? CFPathOrNull : TempPath(".txt");
   Vector<std::string> NewFiles;
-  Set<uint32_t> NewFeatures;
+  Set<uint32_t> NewFeatures, NewCov;
   CrashResistantMerge(Args, OldCorpus, NewCorpus, &NewFiles, {}, &NewFeatures,
-                      CFPath, true);
+                      {}, &NewCov, CFPath, true);
   for (auto &Path : NewFiles)
     F->WriteToOutputCorpus(FileToVector(Path, Options.MaxLen));
   // We are done, delete the control file if it was a temporary one.
diff --git a/FuzzerFork.cpp b/FuzzerFork.cpp
index 7c82f3f..41fb5c1 100644
--- a/FuzzerFork.cpp
+++ b/FuzzerFork.cpp
@@ -72,7 +72,7 @@
   Vector<std::string> CorpusDirs;
   std::string MainCorpusDir;
   std::string TempDir;
-  Set<uint32_t> Features;
+  Set<uint32_t> Features, Cov;
   Vector<std::string> Files;
   Random *Rand;
   int Verbosity = 0;
@@ -122,9 +122,9 @@
     GetSizedFilesFromDir(Job->CorpusDir, &TempFiles);
 
     Vector<std::string> FilesToAdd;
-    Set<uint32_t> NewFeatures;
+    Set<uint32_t> NewFeatures, NewCov;
     CrashResistantMerge(Args, {}, TempFiles, &FilesToAdd, Features,
-                        &NewFeatures, Job->CFPath, false);
+                        &NewFeatures, Cov, &NewCov, Job->CFPath, false);
     RemoveFile(Job->CFPath);
     for (auto &Path : FilesToAdd) {
       auto U = FileToVector(Path);
@@ -134,11 +134,12 @@
     }
     RmDirRecursive(Job->CorpusDir);
     Features.insert(NewFeatures.begin(), NewFeatures.end());
+    Cov.insert(NewCov.begin(), NewCov.end());
     auto Stats = ParseFinalStatsFromLog(Job->LogPath);
     NumRuns += Stats.number_of_executed_units;
     if (!FilesToAdd.empty())
-      Printf("#%zd: ft: %zd corp: %zd exec/s %zd\n", NumRuns,
-             Features.size(), Files.size(),
+      Printf("#%zd: cov: %zd ft: %zd corp: %zd exec/s %zd\n", NumRuns,
+             Cov.size(), Features.size(), Files.size(),
              Stats.average_exec_per_sec);
   }
 };
@@ -202,6 +203,7 @@
 
   auto CFPath = DirPlusFile(Env.TempDir, "merge.txt");
   CrashResistantMerge(Env.Args, {}, SeedFiles, &Env.Files, {}, &Env.Features,
+                      {}, &Env.Cov,
                       CFPath, false);
   RemoveFile(CFPath);
   Printf("INFO: -fork=%d: %zd seeds, starting to fuzz; scratch: %s\n",
diff --git a/FuzzerMerge.cpp b/FuzzerMerge.cpp
index 55e5c9a..549d180 100644
--- a/FuzzerMerge.cpp
+++ b/FuzzerMerge.cpp
@@ -77,7 +77,7 @@
   const size_t kInvalidStartMarker = -1;
   size_t LastSeenStartMarker = kInvalidStartMarker;
   Vector<uint32_t> TmpFeatures;
-  Set<uintptr_t> PCs;
+  Set<uint32_t> PCs;
   while (std::getline(IS, Line, '\n')) {
     std::istringstream ISS1(Line);
     std::string Marker;
@@ -106,10 +106,11 @@
         Files[CurrentFileIdx].Features = TmpFeatures;
       }
     } else if (Marker == "COV") {
+      size_t CurrentFileIdx = N;
       if (ParseCoverage)
         while (ISS1 >> std::hex >> N)
           if (PCs.insert(N).second)
-            NumCoveredPCs++;
+            Files[CurrentFileIdx].Cov.push_back(N);
     } else {
       return false;
     }
@@ -130,9 +131,9 @@
 
 // Decides which files need to be merged (add those to NewFiles).
 // Returns the number of new features added.
-size_t Merger::Merge(const Set<uint32_t> &InitialFeatures,
-                     Set<uint32_t> *NewFeatures,
-                     Vector<std::string> *NewFiles) {
+void Merger::Merge(const Set<uint32_t> &InitialFeatures,
+                   Set<uint32_t> *NewFeatures, const Set<uint32_t> &InitialCov,
+                   Set<uint32_t> *NewCov, Vector<std::string> *NewFiles) {
   NewFiles->clear();
   assert(NumFilesInFirstCorpus <= Files.size());
   Set<uint32_t> AllFeatures = InitialFeatures;
@@ -142,8 +143,6 @@
     auto &Cur = Files[i].Features;
     AllFeatures.insert(Cur.begin(), Cur.end());
   }
-  size_t InitialNumFeatures = AllFeatures.size();
-
   // Remove all features that we already know from all other inputs.
   for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
     auto &Cur = Files[i].Features;
@@ -178,8 +177,10 @@
     }
     if (FoundNewFeatures)
       NewFiles->push_back(Files[i].Name);
+    for (auto Cov : Files[i].Cov)
+      if (InitialCov.find(Cov) == InitialCov.end())
+        NewCov->insert(Cov);
   }
-  return AllFeatures.size() - InitialNumFeatures;
 }
 
 Set<uint32_t> Merger::AllFeatures() const {
@@ -241,7 +242,7 @@
     for (size_t F : UniqFeatures)
       OF << " " << std::hex << F;
     OF << "\n";
-    OF << "COV " << i;
+    OF << "COV " << std::dec << i;
     TPC.ForEachObservedPC([&](const TracePC::PCTableEntry *TE) {
       if (AllPCs.insert(TE).second)
         OF << " " << TPC.PCTableEntryIdx(TE);
@@ -276,7 +277,10 @@
                          const Vector<SizedFile> &NewCorpus,
                          Vector<std::string> *NewFiles,
                          const Set<uint32_t> &InitialFeatures,
-                         Set<uint32_t> *NewFeatures, const std::string &CFPath,
+                         Set<uint32_t> *NewFeatures,
+                         const Set<uint32_t> &InitialCov,
+                         Set<uint32_t> *NewCov,
+                         const std::string &CFPath,
                          bool V /*Verbose*/) {
   if (NewCorpus.empty() && OldCorpus.empty()) return;  // Nothing to merge.
   size_t NumAttempts = 0;
@@ -346,9 +350,10 @@
   VPrintf(V,
           "MERGE-OUTER: consumed %zdMb (%zdMb rss) to parse the control file\n",
           M.ApproximateMemoryConsumption() >> 20, GetPeakRSSMb());
-  size_t NumNewFeatures = M.Merge(InitialFeatures, NewFeatures, NewFiles);
-  VPrintf(V, "MERGE-OUTER: %zd new files with %zd new features added\n",
-         NewFiles->size(), NumNewFeatures);
+  M.Merge(InitialFeatures, NewFeatures, InitialCov, NewCov, NewFiles);
+  VPrintf(V, "MERGE-OUTER: %zd new files with %zd new features added; "
+          "%zd new coverage edges\n",
+         NewFiles->size(), NewFeatures->size(), NewCov->size());
 }
 
 } // namespace fuzzer
diff --git a/FuzzerMerge.h b/FuzzerMerge.h
index 157611c..7a0cd4b 100644
--- a/FuzzerMerge.h
+++ b/FuzzerMerge.h
@@ -51,12 +51,11 @@
 struct MergeFileInfo {
   std::string Name;
   size_t Size = 0;
-  Vector<uint32_t> Features;
+  Vector<uint32_t> Features, Cov;
 };
 
 struct Merger {
   Vector<MergeFileInfo> Files;
-  size_t NumCoveredPCs = 0;
   size_t NumFilesInFirstCorpus = 0;
   size_t FirstNotProcessedFile = 0;
   std::string LastFailure;
@@ -64,9 +63,9 @@
   bool Parse(std::istream &IS, bool ParseCoverage);
   bool Parse(const std::string &Str, bool ParseCoverage);
   void ParseOrExit(std::istream &IS, bool ParseCoverage);
-  size_t Merge(const Set<uint32_t> &InitialFeatures,
-               Set<uint32_t> *NewFeatures,
-               Vector<std::string> *NewFiles);
+  void Merge(const Set<uint32_t> &InitialFeatures, Set<uint32_t> *NewFeatures,
+             const Set<uint32_t> &InitialCov, Set<uint32_t> *NewCov,
+             Vector<std::string> *NewFiles);
   size_t ApproximateMemoryConsumption() const;
   Set<uint32_t> AllFeatures() const;
 };
@@ -77,6 +76,8 @@
                          Vector<std::string> *NewFiles,
                          const Set<uint32_t> &InitialFeatures,
                          Set<uint32_t> *NewFeatures,
+                         const Set<uint32_t> &InitialCov,
+                         Set<uint32_t> *NewCov,
                          const std::string &CFPath,
                          bool Verbose);