diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1a87247323e..6fc0c826d4c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-10-19  Iain Sandoe  <iain@sandoe.co.uk>
+
+	* gcc.dg/Wnonnull.c: Add attributed function declarations for
+	memcpy and strlen for Darwin.
+
 2019-10-18  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/92157
diff --git a/gcc/testsuite/gcc.dg/Wnonnull.c b/gcc/testsuite/gcc.dg/Wnonnull.c
index be89a5a755c..a165baa99f5 100644
--- a/gcc/testsuite/gcc.dg/Wnonnull.c
+++ b/gcc/testsuite/gcc.dg/Wnonnull.c
@@ -2,7 +2,16 @@
    { dg-do compile }
    { dg-options "-O2 -Wall" } */
 
+#ifndef __APPLE__
 #include <string.h>
+#else
+/* OSX headers do not mark up the nonnull elements yet.  */
+# include <stddef.h>
+extern size_t strlen (const char *__s)
+		      __attribute ((pure)) __attribute ((nonnull (1)));
+extern void *memcpy (void *__restrict __dest, const void *__restrict __src,
+		     size_t __n) __attribute ((nonnull (1, 2)));
+#endif
 
 char buf[100];