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[committed] alpha: Use saturating arithmetic in memchr

Message ID 20170201224129.29715-1-rth@twiddle.net
State New
Headers show

Commit Message

Richard Henderson Feb. 1, 2017, 10:41 p.m. UTC 
Like the PRs for x86 and powerpc, alpha can overflow N
depending on alignment.


r~


	* sysdeps/alpha/memchr.c (__memchr): Use saturating arithmetic
	adjusting the byte count.
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Patch

diff --git a/sysdeps/alpha/memchr.c b/sysdeps/alpha/memchr.c
index 82c42c0..402088d 100644
--- a/sysdeps/alpha/memchr.c
+++ b/sysdeps/alpha/memchr.c
@@ -53,7 +53,10 @@  __memchr (const void *s, int xc, size_t n)
   /* Align the source, and decrement the count by the number
      of bytes searched in the first word.  */
   s_align = (const word *)((word)s & -8);
-  n += ((word)s & 7);
+  {
+    size_t inc = n + ((word)s & 7);
+    n = inc | -(inc < n);
+  }
 
   /* Deal with misalignment in the first word for the comparison.  */
   mask = (1ul << ((word)s & 7)) - 1;