diff --git a/src/backend/regex/regexec.c b/src/backend/regex/regexec.c
index 0edb83c1099..2e976627f52 100644
--- a/src/backend/regex/regexec.c
+++ b/src/backend/regex/regexec.c
@@ -259,6 +259,7 @@ pg_regexec(regex_t *re,
 	/* clean up */
 	if (v->pmatch != pmatch && v->pmatch != mat)
 		FREE(v->pmatch);
+	n = (size_t) v->g->ntree;
 	for (i = 0; i < n; i++)
 	{
 		if (v->subdfas[i] != NULL)