diff --git a/src/evalfunc.c b/src/evalfunc.c
index f065026..55041b9 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -9966,7 +9966,9 @@
     pat = tv_get_string_buf_chk(&argvars[1], patbuf);
     flg = tv_get_string_buf_chk(&argvars[3], flagsbuf);
 
-    if (argvars[2].v_type == VAR_FUNC || argvars[2].v_type == VAR_PARTIAL)
+    if (argvars[2].v_type == VAR_FUNC
+	    || argvars[2].v_type == VAR_PARTIAL
+	    || argvars[2].v_type == VAR_INSTR)
 	expr = &argvars[2];
     else
 	sub = tv_get_string_buf_chk(&argvars[2], subbuf);