PR c/54391 - transparent_union typedef'ing inconsistent

gcc/testsuite/ChangeLog:
	* gcc.dg/transparent-union-6.c: New.

From-SVN: r265024

gcc/testsuite/ChangeLog

 2018-10-10  Martin Sebor  <msebor@redhat.com>
 
+	PR c/54391
+	* gcc.dg/transparent-union-6.c: New.
+
+2018-10-10  Martin Sebor  <msebor@redhat.com>
+
 	* gcc.c-torture/execute/memchr-1.c: Avoid assuming 4-byte wchar_t.
 	Add a test for 2-byte wchar_t.
 	* gcc.dg/builtin-memchr.c: New test.

gcc/testsuite/gcc.dg/transparent-union-6.c

+/* PR c/54391 - transparent_union typedef'ing inconsistent
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+typedef union m30_u m30_t;
+
+union __attribute__((transparent_union)) m30_u {
+  int u;
+};
+
+double make_double (m30_t);
+
+double f (void)
+{
+  int bar = 17;
+  return make_double (bar);
+}