https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105882
Bug ID: 105882
Summary: A possible constexpr bug
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: zhonghao at pku dot org.cn
Target Milestone: ---
The code sample is as follows:
#include <complex>
struct real128
{
__float128 m_value;
template <typename T>
constexpr bool get(T &rop) const
{
using value_type = typename T::value_type;
rop.real(static_cast<value_type>(m_value));
rop.imag(static_cast<value_type>(0));
return true;
}
};
constexpr auto fappo(real128 x)
{
std::complex<double> ret{1,2};
x.get(ret);
return ret;
}
constexpr auto flap = fappo(real128{4});
gcc rejects this code, but clang accepts it. mp++ is a library for
multiprecision arithmetic. Its programmers disable several code lines, when gcc
compiles this project. Please check:
https://github.com/bluescarni/mppp/commit/628651b9928e35dc09c0c2de3d2561abababb55f
