diff --git a/ivlpp/lexor.lex b/ivlpp/lexor.lex
index 5fbfd4a19..bc34a1fac 100644
--- a/ivlpp/lexor.lex
+++ b/ivlpp/lexor.lex
@@ -1485,8 +1485,10 @@ static void macro_start_args(void)
      * entry for arg 0. This will be used by macro_finish_arg() to
      * calculate the buffer location for arg 1.
      */
-    def_buf_free = def_buf_size - 1;
-    def_buf[0] = 0;
+    if (def_buf) {
+      def_buf_free = def_buf_size - 1;
+      def_buf[0] = 0;
+    }
     def_argo[0] = 0;
     def_argl[0] = 0;
     def_argc = 1;
diff --git a/ivtest/ivltests/macro_args.v b/ivtest/ivltests/macro_args.v
new file mode 100644
index 000000000..c23e832c0
--- /dev/null
+++ b/ivtest/ivltests/macro_args.v
@@ -0,0 +1,8 @@
+`ifndef FOO
+`define FOO
+`define BAR(x)
+`endif
+
+module macro_args();
+	macro_args_sub sub();
+endmodule
diff --git a/ivtest/ivltests/macro_args_sub.v b/ivtest/ivltests/macro_args_sub.v
new file mode 100644
index 000000000..38241285e
--- /dev/null
+++ b/ivtest/ivltests/macro_args_sub.v
@@ -0,0 +1,3 @@
+module macro_args_sub();
+	`BAR(0)
+endmodule
diff --git a/ivtest/regress-vlg.list b/ivtest/regress-vlg.list
index 2b8274d21..df929e4c1 100644
--- a/ivtest/regress-vlg.list
+++ b/ivtest/regress-vlg.list
@@ -628,6 +628,7 @@ lh_varindx5		normal			ivltests
 localparam_type		normal			ivltests gold=parameter_type.gold
 long_div		normal			ivltests gold=long_div.gold
 macro2			normal			ivltests
+macro_args		CO,-yivltests			ivltests
 macro_redefinition	normal,-Wmacro-redefinition	ivltests gold=macro_redefinition.gold
 macro_replacement	normal,-Wmacro-replacement	ivltests gold=macro_replacement.gold
 macsub			normal			ivltests