--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr83609.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,29 @@
+/* PR middle-end/83609 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-tree-forwprop -fno-tree-ccp -fno-tree-fre -fno-tree-pre -fno-code-hoisting" } */
+
+#if __SIZEOF_LONG_LONG__ == 2 * __SIZEOF_FLOAT__
+_Complex float
+foo (void)
+{
+  _Complex float c;
+  *((unsigned long long *)&c) = 0x123456789abcdef0ULL;
+  return c;
+}
+
+int
+main ()
+{
+  union { _Complex float c; unsigned long long l; } u;
+  u.c = foo ();
+  if (u.l != 0x123456789abcdef0ULL)
+    __builtin_abort ();
+  return 0;
+}
+#else
+int
+main ()
+{
+  return 0;
+}
+#endif