isl_tab.c: push_union: handle NULL input

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/isl_tab.c b/isl_tab.c
index 6089f3a..3fc0367 100644 (file)
--- a/isl_tab.c
+++ b/isl_tab.c
@@ -787,6 +787,8 @@ static int push_union(struct isl_tab *tab,
 {
        struct isl_tab_undo *undo;
 
+       if (!tab)
+               return -1;
        if (!tab->need_undo)
                return 0;