--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr80803.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,72 @@
+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+struct S0
+{
+  unsigned a : 15;
+  int b;
+  int c;
+};
+
+struct S1
+{
+  struct S0 s0;
+  int e;
+};
+
+struct Z
+{
+  char c;
+  int z;
+} __attribute__((packed));
+
+union U
+{
+  struct S1 s1;
+  struct Z z;
+};
+
+
+int __attribute__((noinline, noclone))
+return_zero (void)
+{
+  return 0;
+}
+
+volatile union U gu;
+struct S0 gs;
+
+int __attribute__((noinline, noclone))
+check_outcome ()
+{
+  if (gs.a != 6
+      || gs.b != 80000)
+    __builtin_abort ();
+}
+
+int
+main (int argc, char *argv[])
+{
+  union U u;
+  struct S1 m,n;
+  struct S0 l;
+
+  if (return_zero ())
+    u.z.z = 20000;
+  else
+    {
+      u.s1.s0.a = 6;
+      u.s1.s0.b = 80000;
+      u.s1.e = 2;
+
+      n = u.s1;
+      m = n;
+      m.s0.c = 0;
+      l = m.s0;
+      gs = l;
+    }
+
+  gu = u;
+  check_outcome ();
+  return 0;
+}