diff --git a/src/V3DfgBreakCycles.cpp b/src/V3DfgBreakCycles.cpp
index b4e2f1cdb..4c429fb6c 100644
--- a/src/V3DfgBreakCycles.cpp
+++ b/src/V3DfgBreakCycles.cpp
@@ -496,6 +496,41 @@ class TraceDriver final : public DfgVisitor {
         }
     }
 
+    void visit(DfgExtendS* vtxp) override {
+        DfgVertex* const srcp = vtxp->srcp();
+        const uint32_t sWidth = srcp->width();
+        // If the traced bits are wholly in the input
+        if (sWidth > m_msb) {
+            SET_RESULT(trace(srcp, m_msb, m_lsb));
+            return;
+        }
+        // If there is a single traced bit, wholly in the extension
+        if (m_lsb >= sWidth && m_msb == m_lsb) {
+            if (DfgVertex* const sp = trace(srcp, sWidth - 1, sWidth - 1)) SET_RESULT(sp);
+            return;
+        }
+
+        // The rest need a real ExtendS
+        if (!m_aggressive) return;
+
+        // If the traced bits are wholly in the extension
+        if (m_lsb >= sWidth) {
+            if (DfgVertex* const sp = trace(srcp, sWidth - 1, sWidth - 1)) {
+                DfgExtendS* const resp = make<DfgExtendS>(vtxp, m_msb - m_lsb + 1);
+                resp->srcp(sp);
+                SET_RESULT(resp);
+            }
+            return;
+        }
+        // The traced bits span both sides
+        if (DfgVertex* const sp = trace(srcp, sWidth - 1, m_lsb)) {
+            DfgExtendS* const resp = make<DfgExtendS>(vtxp, m_msb - m_lsb + 1);
+            resp->srcp(sp);
+            SET_RESULT(resp);
+            return;
+        }
+    }
+
     void visit(DfgSel* vtxp) override {
         const uint32_t lsb = vtxp->lsb();
         SET_RESULT(trace(vtxp->srcp(), m_msb + lsb, m_lsb + lsb));
@@ -834,6 +869,15 @@ class IndependentBits final : public DfgVisitor {
         m.opSetRange(sWidth, vtxp->width() - sWidth, '0');
     }
 
+    void visit(DfgExtendS* vtxp) override {
+        const DfgVertex* const srcp = vtxp->srcp();
+        const uint32_t sWidth = srcp->width();
+        V3Number& s = MASK(srcp);
+        V3Number& m = MASK(vtxp);
+        m.opSelInto(s, 0, sWidth);
+        m.opSetRange(sWidth, vtxp->width() - sWidth, s.bitIs0(sWidth - 1) ? '0' : '1');
+    }
+
     void visit(DfgNot* vtxp) override {  //
         MASK(vtxp) = MASK(vtxp->srcp());
     }
diff --git a/test_regress/t/t_dfg_break_cycles.v b/test_regress/t/t_dfg_break_cycles.v
index 9aed4d9c1..70d4fad4d 100644
--- a/test_regress/t/t_dfg_break_cycles.v
+++ b/test_regress/t/t_dfg_break_cycles.v
@@ -59,12 +59,24 @@ module t (
   assign SEL[1] = SEL[0];
   assign SEL[2] = SEL[1];
 
-  `signal(EXTEND, 8); // UNOPTFLAT
-  assign EXTEND[0] = rand_a[3];
-  assign EXTEND[3:1] = 3'(EXTEND[0]);
-  assign EXTEND[4] = EXTEND[1];
-  assign EXTEND[6:5] = EXTEND[2:1];
-  assign EXTEND[7] = EXTEND[3];
+  `signal(ZX, 8); // UNOPTFLAT
+  assign ZX[0] = rand_a[3];
+  assign ZX[3:1] = 3'(ZX[0]);
+  assign ZX[4] = ZX[1];
+  assign ZX[6:5] = ZX[2:1];
+  assign ZX[7] = ZX[3];
+
+  `signal(SX_0, 5); // UNOPTFLAT
+  assign SX_0[0] = rand_a[3];
+  assign SX_0[3:1] = 3'(signed'(SX_0[0]));
+  `signal(SX_1, 5); // UNOPTFLAT
+  assign SX_1 = 5'(signed'({rand_a[0], SX_1[1]}));
+  `signal(SX_2, 5); // UNOPTFLAT
+  assign SX_2 = 5'(signed'({rand_a[0], SX_2[2]}));
+  `signal(SX_3, 5); // UNOPTFLAT
+  assign SX_3 = 5'(signed'({rand_a[0], SX_3[3:2]}));
+  `signal(SX_4, 5); // UNOPTFLAT
+  assign SX_4 = 5'(signed'({rand_a[0], SX_4[4:3]}));
 
   `signal(NOT, 3); // UNOPTFLAT
   assign NOT = ~(rand_a[2:0] ^ 3'(NOT[2:1]));