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Re: [patch] libstdc++/56785 reduce space overhead of nested tuples
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Jonathan Wakely <jwakely at redhat dot com>
- Cc: "libstdc++" <libstdc++ at gcc dot gnu dot org>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 20 Jan 2015 09:09:08 -0800
- Subject: Re: [patch] libstdc++/56785 reduce space overhead of nested tuples
- Authentication-results: sourceware.org; auth=none
- References: <20150117002350 dot GN3360 at redhat dot com>
On Fri, Jan 16, 2015 at 4:23 PM, Jonathan Wakely <jwakely@redhat.com> wrote:
> This replaces the current empty _Tuple_impl that terminates the
> recursive inheritance hierarchy, instead adding the extra code to the
> last base class that holds data so that the recursion terminates there
> instead.
>
> The purpose of this is to avoid nested tuples having two instances of
> the same _Tuple_impl<N> base class, which cannot be placed at the same
> address and so take up space despite being empty.
>
> Tested x86_64-linux, committed to trunk.
This may have caused:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64695
--
H.J.