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Re: [PATCH] PR libstdc++/87431 re-adjust never-valueless optimizations
- From: Antony Polukhin <antoshkka at gmail dot com>
- To: Ville Voutilainen <ville dot voutilainen at gmail dot com>
- Cc: Jonathan Wakely <jwakely at redhat dot com>, "libstdc++" <libstdc++ at gcc dot gnu dot org>, gcc-patches List <gcc-patches at gcc dot gnu dot org>, Tim Shen <timshen91 at gmail dot com>
- Date: Thu, 4 Apr 2019 09:03:34 +0300
- Subject: Re: [PATCH] PR libstdc++/87431 re-adjust never-valueless optimizations
- References: <20190403162543.GO943@redhat.com> <CAKqmYPY-r3z4hk0jG208qjPy+ZADcupvy2rsiGWNMqrMmQ-n1g@mail.gmail.com> <CAFk2RUa=+yhTmuPj5c42bTUg0Xr4jf3zzWJFG6thOG_g-SmNXw@mail.gmail.com>
On Wed, Apr 3, 2019, 23:39 Ville Voutilainen <ville.voutilainen@gmail.com>
wrote:
> On Wed, 3 Apr 2019 at 23:32, Antony Polukhin <antoshkka@gmail.com> wrote:
> >
> > Looks good. Covers most of the use cases.
> >
> > Please consider adding filesystem::path, pair, tuple, string_view?,
> error_code, list, deque (myabe all the other containers), optional, variant
> itself (for cases when variant holds another variant).
> >
> > It would be very useful for the _Never_valueless_alt to return true for
> aggregates that hold only never valueles types. Not sure that there is a
> compiler builtin for getting all the aggregates types, but it could be
> implemented via metaprogramming.
>
> What metaprogram is capable of that?
>
This one https://github.com/apolukhin/magic_get
>