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From: "matt at mattborland dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/109883] Stack Overflow in <cmath> functions with
 <stdfloat> types and -std=c++23
Date: Wed, 17 May 2023 12:41:36 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109883

--- Comment #6 from Matt Borland <matt at mattborland dot com> ---
(In reply to Xi Ruoyao from comment #4)
> It seems the function
>=20
> __gnu_cxx::__promote_2<decltype (((__gnu_cxx::__promote_2<_Float64,
> std::__is_integer<_Float64>::__value>::__type)(0))+((__gnu_cxx::
> __promote_2<_Float64, std::__is_integer<_Float64>::__value>::__type)(0))),
> std::__is_integer<decltype (((__gnu_cxx::__promote_2<_Float64,
> std::__is_integer<_Float64>::__value>::__type)(0))+((__gnu_cxx::
> __promote_2<_Float64,
> std::__is_integer<_Float64>::__value>::__type)(0)))>::__value>::__type
> std::pow<_Float64, _Float64>(_Float64, _Float64)
>=20
> is recursing infinitely.

For Boost.Math's implementation of promote_2 we found template specializati=
ons
to be effective:
https://github.com/boostorg/math/pull/978/files#diff-2463d99030329b154489b8=
b34ce1068a34e736cab268c3421b058ca0e516680cR189.=