tile: Check for pointer add overflow in memchr

As was done in b224637928e9, check for large size causing an overflow
in the loop that walks over the array.

Branching out of line here is the fastest approach for handling this
problem, since tile can bundle the instructions to compute the branch
test in parallel with doing the required memchr loop setup computation.

Unfortunately, the existing saturated ops (e.g. tilegx addxsc) are
all signed saturing ops, so don't help with unsigned saturation.

1 files changed, 4 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 5388306806..9498803f7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2017-01-16  Chris Metcalf  <cmetcalf@mellanox.com>
 
+	* sysdeps/tile/tilegx/memchr.c (__memchr): Handle pointer
+	wrap-around.
+	* sysdeps/tile/tilepro/memchr.c (__memchr): Likewise.
+
 	* sysdeps/unix/sysv/linux/tile/ipc_priv.h: New file.
 
 2016-01-14  Siddhesh Poyarekar  <siddhesh@sourceware.org>