[Bug c/117549] Miscompile with -O0 and -O1/2/3

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117549

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
Seems to have started with r6-9085-gd9363c4e3940bf but that commit makes me
even more suspicious of the testcase.