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From: "g.peterhoff@t-online.de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/77776] C++17 std::hypot implementation is poor
Date: Wed, 10 Apr 2024 16:41:49 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D77776

--- Comment #27 from g.peterhoff@t-online.de ---
Hi Matthias,
thanks for your benchmark. I still have 2 questions:

1) Accuracy
The frexp/ldexp variant seems to be the most accurate; is that correct? Then
other constants would have to be used in hypot_gp:
scale_up   =3D std::exp2(Type(limits::max_exponent-1))
scale_down =3D std::exp2(Type(limits::min_exponent-1))

2) Speed
Your benchmark outputs several columns (=CE=94)Latency/(=CE=94)Throughput/S=
peedup. What
exactly do the values stand for; what should be optimized for?

thx
Gero=