diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index f5e66b58c..24b9a060d 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,3 +1,7 @@
+2014-08-19  Richard Earnshaw  <rearnsha@arm.com>
+
+	* libc/machine/aarch64/memchr.S: Add check for zero-sized buffer.
+
 2014-08-18 Corinna Vinschen  <vinschen@redhat.com>
 
 	* libc/include/sys/signal.h: Declare sigaltstack for RTEMS only.
diff --git a/newlib/libc/machine/aarch64/memchr.S b/newlib/libc/machine/aarch64/memchr.S
index eb59a5aad..53f5d6bc0 100644
--- a/newlib/libc/machine/aarch64/memchr.S
+++ b/newlib/libc/machine/aarch64/memchr.S
@@ -79,6 +79,8 @@
 	.endm
 
 def_fn memchr
+	/* Do not dereference srcin if no bytes to compare.  */
+	cbz	cntin, .Lzero_length
 	/*
 	 * Magic constant 0x40100401 allows us to identify which lane matches
 	 * the requested byte.
@@ -166,5 +168,9 @@ def_fn memchr
 	csel	result, xzr, result, eq
 	ret
 
+.Lzero_length:
+	mov	result, #0
+	ret
+
 	.size	memchr, . - memchr
 #endif