Fix undefined NULL pointer arithmetic

Clang 3.3 with -O2 optimisations is especially picky about arithmetic
on NULL pointers. This undefined behavior is turned into optimized out
NULL checks by clang 3.3. Fix the undefined behavior by checking against
the pointer directly, without going back and forth around NULL with
pointer arithmetic.

Reported-by: Zifei Tong <soariez@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 6f09ddbde7cbe25f2afd83c85652c3609512f784..f934c4cabc6a75a625fdef6cc48e460505b66779 100644 (file)
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -463,7 +463,7 @@ void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
        for (cds_lfht_first(ht, iter),                                  \
                        pos = caa_container_of(cds_lfht_iter_get_node(iter), \
                                        __typeof__(*(pos)), member);    \
-               &(pos)->member != NULL;                                 \
+               cds_lfht_iter_get_node(iter) != NULL;                   \
                cds_lfht_next(ht, iter),                                \
                        pos = caa_container_of(cds_lfht_iter_get_node(iter), \
                                        __typeof__(*(pos)), member))
@@ -473,7 +473,7 @@ void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
        for (cds_lfht_lookup(ht, hash, match, key, iter),               \
                        pos = caa_container_of(cds_lfht_iter_get_node(iter), \
                                        __typeof__(*(pos)), member);    \
-               &(pos)->member != NULL;                                 \
+               cds_lfht_iter_get_node(iter) != NULL;                   \
                cds_lfht_next_duplicate(ht, match, key, iter),          \
                        pos = caa_container_of(cds_lfht_iter_get_node(iter), \
                                        __typeof__(*(pos)), member))