[Bug tree-optimization/90883] Generated code is worse if returned struct is unnamed

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90883

--- Comment #20 from Jeffrey A. Law <law at redhat dot com> ---
Just to be clear, the expansion in question happens very early, essentially
pre-gimple, not at the gimple/RTL border and it's driven by a target macro.

I guess another approach would be to write the whole test in gimple so that we
could avoid the paths that query the target macros and ensure DSE gets the code
in a suitable form.