~0 will be signed and negative on any 2s complement system, and
left shifting a negative value has undefined behaviour in C.
Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
---
ccan/idtree/idtree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ccan/idtree/idtree.c b/ccan/idtree/idtree.c
index 5bd8882..6e75450 100644
--- a/ccan/idtree/idtree.c
+++ b/ccan/idtree/idtree.c
@@ -278,7 +278,7 @@ void *idtree_lookup(const struct idtree *idp, int id)
* present. If so, tain't one of ours!
*/
if (n + IDTREE_BITS < 31 &&
- (id & ~(~0 << MAX_ID_SHIFT)) >> (n + IDTREE_BITS))
+ (id & ~(~0U << MAX_ID_SHIFT)) >> (n + IDTREE_BITS))
return NULL;
/* Mask off upper bits we don't use for the search. */
--
2.5.0
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