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Subject: [Bug libstdc++/105308] Specialize for_each
Date: Tue, 19 Apr 2022 16:05:32 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105308

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #1)
> I'm unclear what the request is.

The list isn't super clear to me either, any sensible specialization of a
standard algorithm for a standard container. Even simply
ranges::for_each(std::set,*) looks like it could be a bit faster with a
specialization instead of using iterators.

> Are you proposing this for the parallel
> std::for_each with an execution policy?

Yes, that's the first motivation.

> That code comes from the PSTL project which is part of LLVM,
> and maintained by Intel, so enhancements to it should ideally be done ups=
tream.

But the code would need to use private interfaces of libstdc++'s _Rb_tree. =
Does
PSTL contain a lot of special code, with one variant for libstdc++ / libc++=
 /
other, that uses internals of the datastructures?=