diff --git a/src/V3Dfg.cpp b/src/V3Dfg.cpp
index a619ee9a7..e57f5095c 100644
--- a/src/V3Dfg.cpp
+++ b/src/V3Dfg.cpp
@@ -407,41 +407,6 @@ void DfgGraph::dumpDotFilePrefixed(const string& label) const {
     dumpDotFile(v3Global.debugFilename(filename) + ".dot", label);
 }
 
-// Dump upstream logic cone starting from given vertex
-static void dumpDotUpstreamConeFromVertex(std::ostream& os, const DfgVertex& vtx) {
-    // Work queue for depth first traversal starting from this vertex
-    std::vector<const DfgVertex*> queue{&vtx};
-
-    // Set of already visited vertices
-    std::unordered_set<const DfgVertex*> visited;
-
-    // Depth first traversal
-    while (!queue.empty()) {
-        // Pop next work item
-        const DfgVertex* const itemp = queue.back();
-        queue.pop_back();
-
-        // Mark vertex as visited
-        const bool isFirstEncounter = visited.insert(itemp).second;
-
-        // If we have already visited this vertex during the traversal, then move on.
-        if (!isFirstEncounter) continue;
-
-        // Enqueue all sources of this vertex.
-        itemp->forEachSource([&](const DfgVertex& src) { queue.push_back(&src); });
-
-        // Emit this vertex and all of its source edges
-        dumpDotVertexAndSourceEdges(os, *itemp);
-    }
-
-    // Emit all DfgVarPacked vertices that have external references driven by this vertex
-    vtx.forEachSink([&](const DfgVertex& dst) {
-        if (const DfgVarPacked* const varVtxp = dst.cast<DfgVarPacked>()) {
-            if (varVtxp->hasNonLocalRefs()) dumpDotVertexAndSourceEdges(os, dst);
-        }
-    });
-}
-
 // LCOV_EXCL_START // Debug function for developer use only
 void DfgGraph::dumpDotUpstreamCone(const string& fileName, const DfgVertex& vtx,
                                    const string& name) const {
@@ -454,8 +419,30 @@ void DfgGraph::dumpDotUpstreamCone(const string& fileName, const DfgVertex& vtx,
     if (!name.empty()) *os << "graph [label=\"" << name << "\", labelloc=t, labeljust=l]\n";
     *os << "graph [rankdir=LR]\n";
 
-    // Dump the cone
-    dumpDotUpstreamConeFromVertex(*os, vtx);
+    // Work queue for depth first traversal starting from this vertex
+    std::vector<const DfgVertex*> queue{&vtx};
+
+    // Set of already visited vertices
+    std::unordered_set<const DfgVertex*> visited;
+
+    // Depth first traversal
+    while (!queue.empty()) {
+        // Pop next work item
+        const DfgVertex* const vtxp = queue.back();
+        queue.pop_back();
+
+        // Mark vertex as visited
+        const bool isFirstEncounter = visited.insert(vtxp).second;
+
+        // If we have already visited this vertex during the traversal, then move on.
+        if (!isFirstEncounter) continue;
+
+        // Enqueue all sources of this vertex.
+        vtxp->forEachSource([&](const DfgVertex& src) { queue.push_back(&src); });
+
+        // Emit this vertex and all of its source edges
+        dumpDotVertexAndSourceEdges(*os, *vtxp);
+    }
 
     // Footer
     *os << "}\n";
@@ -465,40 +452,6 @@ void DfgGraph::dumpDotUpstreamCone(const string& fileName, const DfgVertex& vtx,
 }
 // LCOV_EXCL_STOP
 
-void DfgGraph::dumpDotAllVarConesPrefixed(const string& label) const {
-    const string prefix = label.empty() ? name() + "-cone-" : name() + "-" + label + "-cone-";
-    forEachVertex([&](const DfgVertex& vtx) {
-        // Check if this vertex drives a variable referenced outside the DFG.
-        const DfgVarPacked* const sinkp
-            = vtx.findSink<DfgVarPacked>([](const DfgVarPacked& sink) {  //
-                  return sink.hasNonLocalRefs();
-              });
-
-        // We only dump cones driving an externally referenced variable
-        if (!sinkp) return;
-
-        // Open output file
-        const string coneName{prefix + sinkp->nodep()->name()};
-        const string fileName{v3Global.debugFilename(coneName) + ".dot"};
-        const std::unique_ptr<std::ofstream> os{V3File::new_ofstream(fileName)};
-        if (os->fail()) v3fatal("Can't write file: " << fileName);
-
-        // Header
-        *os << "digraph dfg {\n";
-        *os << "graph [label=\"" << coneName << "\", labelloc=t, labeljust=l]\n";
-        *os << "graph [rankdir=LR]\n";
-
-        // Dump this cone
-        dumpDotUpstreamConeFromVertex(*os, vtx);
-
-        // Footer
-        *os << "}\n";
-
-        // Done with this logic cone
-        os->close();
-    });
-}
-
 //------------------------------------------------------------------------------
 // DfgEdge
 //------------------------------------------------------------------------------
diff --git a/src/V3Dfg.h b/src/V3Dfg.h
index cef0b5e72..6af0531ee 100644
--- a/src/V3Dfg.h
+++ b/src/V3Dfg.h
@@ -756,11 +756,6 @@ public:
     // 'filename'. 'name' is the name of the graph, which is included in the output.
     void dumpDotUpstreamCone(const string& filename, const DfgVertex& vtx,
                              const string& name = "") const VL_MT_DISABLED;
-    // Dump all individual logic cones driving external variables in Graphviz format into separate
-    // new automatically numbered debug files. 'label' is added to the name of the graph, which is
-    // included in the file names and the output. This is useful for very large graphs that are
-    // otherwise difficult to browse visually due to their size.
-    void dumpDotAllVarConesPrefixed(const string& label = "") const VL_MT_DISABLED;
 };
 
 // Specializations of privateTypeTest
diff --git a/src/V3DfgPasses.cpp b/src/V3DfgPasses.cpp
index d349551d4..9a9058090 100644
--- a/src/V3DfgPasses.cpp
+++ b/src/V3DfgPasses.cpp
@@ -523,7 +523,6 @@ void V3DfgPasses::optimize(DfgGraph& dfg, V3DfgContext& ctx) {
         ++passNumber;
     };
 
-    if (dumpDfgLevel() >= 8) dfg.dumpDotAllVarConesPrefixed(ctx.prefix() + "input");
     apply(3, "input           ", [&]() {});
     apply(4, "inlineVars      ", [&]() { inlineVars(dfg); });
     apply(4, "cse0            ", [&]() { cse(dfg, ctx.m_cseContext0); });
@@ -538,5 +537,4 @@ void V3DfgPasses::optimize(DfgGraph& dfg, V3DfgContext& ctx) {
     // Accumulate patterns for reporting
     if (v3Global.opt.stats()) ctx.m_patternStats.accumulate(dfg);
     apply(4, "regularize", [&]() { regularize(dfg, ctx.m_regularizeContext); });
-    if (dumpDfgLevel() >= 8) dfg.dumpDotAllVarConesPrefixed(ctx.prefix() + "optimized");
 }