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From: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Mon, 15 Mar 2021 10:20:46 +0000
Message-ID: <CAH6eHdR=aVX0-sXpApXAKOk+wmpsD_i39uf145e_ebJqo8=tsA@mail.gmail.com>
Subject: Re: IEEE Interchange floating point and extended floating point for
 C++
To: Sjoerd Meijer <Sjoerd.Meijer@arm.com>
Cc: Joseph Myers <joseph@codesourcery.com>, Kito Cheng <kito.cheng@gmail.com>,
 GCC <gcc@gcc.gnu.org>
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On Mon, 15 Mar 2021 at 10:17, Sjoerd Meijer wrote:
>
> Many thanks for your replies and thoughts on this.
>
> I wanted to add that I agree with this, and say that this is the
> current state in Clang (exactly because of the reason that
> _Float16 is entirely new):
>
> I see less value in adding additional distinct types that don't add anyth=
ing you can't already do. _Float16 gives you access to an entirely new data=
 type. _Float32 just complicates overloading of it's a new type with the sa=
me representation as an existing one. With the proposed std::float32 typede=
f for C++ users will still be able to write code that definitely uses an IE=
EE binary32 type without needing a new type to be introduced. ISTM that wha=
t users really want is "a type guaranteed to be IEEE binary32" and whether =
that is float or _Float32 is mostly irrelevant.
>
> And isn't the good news that this is all fairly orthogonal
> and a start could be made with _Float16 and others could be
> added later if required?

Yes, so I think that is the right incremental step forwards for C++.