https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89174
--- Comment #3 from Neil Carlson <neil.n.carlson at gmail dot com> --- r265171 is the commit that broke the 9.0 trunk; r265171 segfaults but r265170 works correctly. I haven't been able to pinpoint where this stuff was back-ported to the 8 branch, but it definitely was. This example used to work for 7, 8, and 9.