diff --git a/Changes b/Changes
index 30d299c1f..d7923afde 100644
--- a/Changes
+++ b/Changes
@@ -21,6 +21,7 @@ Verilator 4.201 devel
 * Fix false $dumpfile warning on model save (#2834). [Yinan Xu]
 * Fix --timescale-override not suppressing TIMESCALEMOD (#2838). [Kaleb Barrett]
 * Fix false TIMESCALEMOD on generate-ignored instances (#2838). [Kaleb Barrett]
+* Fix --output-split with class extends (#2839). [Iru Cai]
 
 
 Verilator 4.200 2021-03-12
diff --git a/include/verilated.cpp b/include/verilated.cpp
index 0ee5a46e6..06c632e2e 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -2403,6 +2403,8 @@ void VerilatedContextImp::commandArgVl(const std::string& arg) {
             VL_PRINTF_MT("For help, please see 'verilator --help'\n");
             VL_FATAL_MT("COMMAND_LINE", 0, "",
                         "Exiting due to command line argument (not an error)");
+        } else if (arg == "+verilator+noassert") {
+            assertOn(false);
         } else if (commandArgVlValue(arg, "+verilator+prof+threads+start+", value /*ref*/)) {
             profThreadsStart(atoll(value.c_str()));
         } else if (commandArgVlValue(arg, "+verilator+prof+threads+window+", value /*ref*/)) {
@@ -2413,8 +2415,6 @@ void VerilatedContextImp::commandArgVl(const std::string& arg) {
             randReset(atoi(value.c_str()));
         } else if (commandArgVlValue(arg, "+verilator+seed+", value /*ref*/)) {
             randSeed(atoi(value.c_str()));
-        } else if (arg == "+verilator+noassert") {
-            assertOn(false);
         } else if (arg == "+verilator+V") {
             VerilatedImp::versionDump();  // Someday more info too
             VL_FATAL_MT("COMMAND_LINE", 0, "",
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index 0ea41997c..a83efb16b 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -1853,7 +1853,7 @@ class EmitCImp final : EmitCStmts {
     void emitTextSection(AstType type);
     // High level
     void emitImpTop(AstNodeModule* modp);
-    void emitImp(AstNodeModule* modp);
+    void emitImp(AstNodeModule* fileModp, AstNodeModule* modp);
     void emitSettleLoop(const std::string& eval_call, bool initial);
     void emitWrapEval(AstNodeModule* modp);
     void emitWrapFast(AstNodeModule* modp);
@@ -3351,7 +3351,7 @@ void EmitCImp::emitImpTop(AstNodeModule* fileModp) {
     emitTextSection(AstType::atScImpHdr);
 }
 
-void EmitCImp::emitImp(AstNodeModule* modp) {
+void EmitCImp::emitImp(AstNodeModule* fileModp, AstNodeModule* modp) {
     puts("\n//==========\n");
     if (m_slow) {
         string section;
@@ -3374,7 +3374,7 @@ void EmitCImp::emitImp(AstNodeModule* modp) {
     // Blocks
     for (AstNode* nodep = modp->stmtsp(); nodep; nodep = nodep->nextp()) {
         if (AstCFunc* funcp = VN_CAST(nodep, CFunc)) {
-            maybeSplit(modp);
+            maybeSplit(fileModp);
             mainDoFunc(funcp);
         }
     }
@@ -3427,14 +3427,14 @@ void EmitCImp::mainImp(AstNodeModule* modp, bool slow) {
 
     m_ofp = newOutCFile(fileModp, !m_fast, true /*source*/);
     emitImpTop(fileModp);
-    emitImp(modp);
+    emitImp(fileModp, modp);
 
     if (AstClassPackage* packagep = VN_CAST(modp, ClassPackage)) {
         // Put the non-static class implementation in same C++ files as
         // often optimizations are possible when both are seen by the
         // compiler together
         m_modp = packagep->classp();
-        emitImp(packagep->classp());
+        emitImp(fileModp, packagep->classp());
         m_modp = modp;
     }
 
@@ -3447,7 +3447,7 @@ void EmitCImp::mainImp(AstNodeModule* modp, bool slow) {
              vxp = vxp->verticesNextp()) {
             const ExecMTask* mtaskp = dynamic_cast<const ExecMTask*>(vxp);
             if (mtaskp->threadRoot()) {
-                maybeSplit(modp);
+                maybeSplit(fileModp);
                 // Only define one function for all the mtasks packed on
                 // a given thread. We'll name this function after the
                 // root mtask though it contains multiple mtasks' worth
diff --git a/test_regress/t/t_class_split.pl b/test_regress/t/t_class_split.pl
new file mode 100755
index 000000000..2dd83547c
--- /dev/null
+++ b/test_regress/t/t_class_split.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    verilator_flags2 => ['--output-split 10'],
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_class_split.v b/test_regress/t/t_class_split.v
new file mode 100644
index 000000000..7c6a6b8e8
--- /dev/null
+++ b/test_regress/t/t_class_split.v
@@ -0,0 +1,34 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2021 by Iru Cai.
+// SPDX-License-Identifier: CC0-1.0
+
+class Cls1;
+   int ctr;
+   task run();
+      $display("%d", ctr);
+      ctr = ctr + 1;
+   endtask: run
+endclass;
+
+class Cls2 extends Cls1;
+   task runtask();
+      run();
+      run();
+      run();
+      run();
+      run();
+      run();
+   endtask: runtask
+endclass
+
+module top;
+   Cls2 o;
+   initial begin
+      o = new;
+      o.runtask();
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule