https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111264
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2023-09-01
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Hans-Peter Nilsson from comment #1)
> Also seen for cris-elf and m68k-linux
> (https://gcc.gnu.org/pipermail/gcc-testresults/2023-August/794806.html).
>
> Some experimentation says that this is a mismatch between the default C++
> version for the host/installed gcc (for me, C++11, I think) and the target
> (C++17, right?). If you add "-std=c++17" to the invocation line in gcc.log,
> compilation succeeds. Or, change the form of the newly introduced
> declarations from
> auto foobar = foo<bar>();
> to
> foo<bar> foobar;
> Not sure why the former is used, it seems negate the benefits of auto and
> just be more typing. Beware: since I know Very Little C++ of the last
> decades, I could be completely wrong.
You are mostly correct.
In C++17, Copy elision is guaranteed to be done here while in earlier versions
it is not and earlier versions of C++ require a copy/move constructor even if
copy elision is to be done. See
https://en.cppreference.com/w/cpp/language/copy_elision for more information.
