diff --git a/search/ClkInfo.cc b/search/ClkInfo.cc
index 409f50b8..8025a0ba 100644
--- a/search/ClkInfo.cc
+++ b/search/ClkInfo.cc
@@ -128,8 +128,8 @@ ClkInfo::crprClkPath(const StaState *sta) const
   return Path::vertexPath(crpr_clk_path_, sta);
 }
 
-const char *
-ClkInfo::asString(const StaState *sta) const
+std::string
+ClkInfo::to_string(const StaState *sta) const
 {
   Network *network = sta->network();
   Corners *corners = sta->corners();
@@ -160,9 +160,7 @@ ClkInfo::asString(const StaState *sta) const
   if (is_gen_clk_src_path_)
     result += " genclk";
 
-  char *tmp = makeTmpString(result.size() + 1);
-  strcpy(tmp, result.c_str());
-  return tmp;
+  return result;
 }
 
 const Clock *
diff --git a/search/ClkInfo.hh b/search/ClkInfo.hh
index 8d1d82d1..f4706ee1 100644
--- a/search/ClkInfo.hh
+++ b/search/ClkInfo.hh
@@ -49,7 +49,7 @@ public:
 	  Path *crpr_clk_path,
 	  const StaState *sta);
   ~ClkInfo();
-  const char *asString(const StaState *sta) const;
+  std::string to_string(const StaState *sta) const;
   const ClockEdge *clkEdge() const { return clk_edge_; }
   const Clock *clock() const;
   const Pin *clkSrc() const { return clk_src_; }
diff --git a/search/Search.cc b/search/Search.cc
index c143dd3c..13c9fe89 100644
--- a/search/Search.cc
+++ b/search/Search.cc
@@ -2965,7 +2965,7 @@ Search::reportClkInfos() const
     clk_infos.push_back(clk_info);
   sort(clk_infos, ClkInfoLess(this));
   for (ClkInfo *clk_info : clk_infos)
-    report_->reportLine("%s", clk_info->asString(this));
+    report_->reportLine("%s", clk_info->to_string(this).c_str());
   report_->reportLine("%zu clk infos", clk_info_set_->size());
 }
 
diff --git a/search/Sta.cc b/search/Sta.cc
index 0ef56510..8e69e355 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -541,7 +541,7 @@ Sta::~Sta()
   delete clk_skews_;
   delete check_timing_;
   delete report_path_;
-  // Constraints reference search filter, so delete search first.
+  // Sdc references search filter, so delete search first.
   delete search_;
   delete latches_;
   delete parasitics_;
@@ -4598,7 +4598,7 @@ Sta::deletePinBefore(const Pin *pin)
           Edge *edge = in_edge_iter.next();
           if (edge->role()->isWire()) {
             Vertex *from = edge->from(graph_);
-            // Only notify from vertex (to vertex will be deleted).
+            // Only notify to_vertex (from_vertex will be deleted).
             search_->requiredInvalid(from);
           }
           levelize_->deleteEdgeBefore(edge);
diff --git a/search/Tag.cc b/search/Tag.cc
index 69269cf8..d064c0f2 100644
--- a/search/Tag.cc
+++ b/search/Tag.cc
@@ -293,25 +293,22 @@ bool
 TagLess::operator()(const Tag *tag1,
 		    const Tag *tag2) const
 {
-  return tagCmp(tag1, tag2, true) < 0;
+  return tagCmp(tag1, tag2) < 0;
 }
 
 int
 tagCmp(const Tag *tag1,
-       const Tag *tag2,
-       bool cmp_rf)
+       const Tag *tag2)
 {
   if (tag1 == tag2)
     return 0;
 
-  if (cmp_rf) {
-    int rf_index1 = tag1->rfIndex();
-    int rf_index2 = tag2->rfIndex();
-    if (rf_index1 < rf_index2)
-      return -1;
-    if (rf_index1 > rf_index2)
-      return 1;
-  }
+  int rf_index1 = tag1->rfIndex();
+  int rf_index2 = tag2->rfIndex();
+  if (rf_index1 < rf_index2)
+    return -1;
+  if (rf_index1 > rf_index2)
+    return 1;
 
   PathAPIndex path_ap_index1 = tag1->pathAPIndex();
   PathAPIndex path_ap_index2 = tag2->pathAPIndex();
diff --git a/search/Tag.hh b/search/Tag.hh
index 4317cd4b..35d46cba 100644
--- a/search/Tag.hh
+++ b/search/Tag.hh
@@ -138,8 +138,7 @@ public:
 
 int
 tagCmp(const Tag *tag1,
-       const Tag *tag2,
-       bool cmp_rf);
+       const Tag *tag2);
 
 // Match tag clock edge, clock driver and exception states but not clk info.
 bool