This test uses std::is_integral to decide whether we are testing an integral or floating-point type. But that fails for __int128 because is_integral<__int128> is false in strict modes. By using numeric_limits::is_integer instead we get the right answer for all types that have a numeric_limits specialization.
We can also simplify the test by removing the unnecessary tag dispatching. libstdc++-v3/ChangeLog: * testsuite/18_support/numeric_limits/lowest.cc: Use numeric_limits<T>::is_integer instead of is_integral<T>::value. Tested powerpc64le-linux. Committed to trunk.
commit 45ba5426c129993704a73e6ace4016eaa950d7ee Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Oct 11 13:28:32 2021 libstdc++: Fix std::numeric_limits::lowest() test for strict modes This test uses std::is_integral to decide whether we are testing an integral or floating-point type. But that fails for __int128 because is_integral<__int128> is false in strict modes. By using numeric_limits::is_integer instead we get the right answer for all types that have a numeric_limits specialization. We can also simplify the test by removing the unnecessary tag dispatching. libstdc++-v3/ChangeLog: * testsuite/18_support/numeric_limits/lowest.cc: Use numeric_limits<T>::is_integer instead of is_integral<T>::value. diff --git a/libstdc++-v3/testsuite/18_support/numeric_limits/lowest.cc b/libstdc++-v3/testsuite/18_support/numeric_limits/lowest.cc index 54866966ee0..abc967c60f8 100644 --- a/libstdc++-v3/testsuite/18_support/numeric_limits/lowest.cc +++ b/libstdc++-v3/testsuite/18_support/numeric_limits/lowest.cc @@ -23,30 +23,20 @@ // 18.2.1.1 template class numeric_limits #include <limits> -#include <type_traits> #include <testsuite_hooks.h> template<typename T> void - do_test(std::true_type) + do_test() { T limits_min = std::numeric_limits<T>::min(); - VERIFY( std::numeric_limits<T>::lowest() == limits_min ); - } - -template<typename T> - void - do_test(std::false_type) - { T limits_max = std::numeric_limits<T>::max(); - VERIFY( std::numeric_limits<T>::lowest() == -limits_max ); + if (std::numeric_limits<T>::is_integer) + VERIFY( std::numeric_limits<T>::lowest() == limits_min ); + else + VERIFY( std::numeric_limits<T>::lowest() == -limits_max ); } -template<typename Tp> - void - do_test() - { do_test<Tp>(typename std::is_integral<Tp>::type()); } - void test01() { do_test<char>();