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From: "mkretz at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/114417] std::experimental::simd is not a POD (by ABI
 definitions) and is always passed by reference instead of by value
Date: Mon, 22 Apr 2024 12:46:01 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114417

Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mkretz at gcc dot gnu.org

--- Comment #9 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> ---
Sorry for not noticing this PR earlier. Yes, this specific behavior of
fixed_size follows a request from the C++ committee for the TS. It is not
mandated by the TS wording, because the C++ spec has no means to require
passing arguments via the stack or registers. That's beyond the abstract
machine. It still asks for that behavior non-normatively, though.

What you want to use instead is std::experimental::simd_abi::deduce_t<T, N>.
That'll give you a not-fixed_size ABI if one exists. And those will likely =
be
passed via registers (as long as the psABI allows).=