--- gcc-5.3.0/gcc/builtins.c.orig	2016-10-18 10:45:35.042826368 +0200
+++ gcc-5.3.0/gcc/builtins.c	2016-10-18 10:50:46.080616285 +0200
@@ -3470,6 +3470,19 @@ expand_builtin_mempcpy_args (tree dest,
 # define CODE_FOR_movstr CODE_FOR_nothing
 #endif
 
+/* Return true if STR is a string denoting a "/gnu/store" file name.  */
+
+static bool
+store_reference_p (tree str)
+{
+  const char *store;
+
+  store = getenv ("NIX_STORE") ?: "/gnu/store";
+
+  return (TREE_STRING_LENGTH (str) > strlen (store)
+	  && strncmp (TREE_STRING_POINTER (str), store, strlen (store)));
+}
+
 /* Expand into a movstr instruction, if one is available.  Return NULL_RTX if
    we failed, the caller should emit a normal call, otherwise try to
    get the result in TARGET, if convenient.  If ENDP is 0 return the
@@ -3484,7 +3497,9 @@ expand_movstr (tree dest, tree src, rtx
   rtx dest_mem;
   rtx src_mem;
 
-  if (!HAVE_movstr)
+  /* When SRC denotes a store item, do not perform any optimization.  See
+     <http://bugs.gnu.org/24703> for background.  */
+  if (!HAVE_movstr || store_reference_p (src))
     return NULL_RTX;
 
   dest_mem = get_memory_rtx (dest, NULL);