isl_map_subtract.c: tab_add_constraints: avoid NULL pointer dereference

diff --git a/isl_map_subtract.c b/isl_map_subtract.c
index 2cbdb01..53664c5 100644 (file)
--- a/isl_map_subtract.c
+++ b/isl_map_subtract.c
@@ -49,6 +49,8 @@ static int tab_add_constraints(struct isl_tab *tab,
                return -1;
 
        v = isl_vec_alloc(bmap->ctx, 1 + tab_total);
+       if (!v)
+               return -1;
 
        for (i = 0; i < bmap->n_eq; ++i) {
                expand_constraint(v, dim, bmap->eq[i], div_map, bmap->n_div);