diff --git a/grep.c b/grep.c
index be99b34168..f3a27d7d6e 100644
--- a/grep.c
+++ b/grep.c
@@ -192,7 +192,8 @@ void compile_grep_patterns(struct grep_opt *opt)
 	 * A classic recursive descent parser would do.
 	 */
 	p = opt->pattern_list;
-	opt->pattern_expression = compile_pattern_expr(&p);
+	if (p)
+		opt->pattern_expression = compile_pattern_expr(&p);
 	if (p)
 		die("incomplete pattern expression: %s", p->pattern);
 }