On 19/08/20 20:36 +0100, Jonathan Wakely wrote:
>On 19/08/20 17:00 +0100, Jonathan Wakely wrote:
>>Because __int128 can be used as the difference type for iota_view, we
>>need to ensure that it meets the requirements of an integer-class type.
>>The requirements in [iterator.concept.winc] p10 include numeric_limits
>>being specialized and giving meaningful answers. Currently we only
>>specialize numeric_limits for non-standard integer types in non-strict
>>modes.  However, nothing prevents us from defining an explicit
>>specialization for any implementation-defined type, so it doesn't matter
>>whether std::is_integral<__int128> is true or not.
>>
>>This patch ensures that the numeric_limits specializations for signed
>>and unsigned __int128 are defined whenever __int128 is available. It
>>also makes the __numeric_traits and __int_limits helpers work for
>>__int128, via a new __gnu_cxx::__is_integer_nonstrict trait.
>>
>>libstdc++-v3/ChangeLog:
>>
>>	PR libstdc++/96042
>>	* include/ext/numeric_traits.h (__is_integer_nonstrict): New
>>	trait which is true for 128-bit integers even in strict modes.
>>	(__numeric_traits_integer, __numeric_traits): Use
>>	__is_integer_nonstrict instead of __is_integer.
>>	* include/std/limits [__STRICT_ANSI__ && __SIZEOF_INT128__]
>>	(numeric_limits<__int128>, (numeric_limits<unsigned __int128>):
>>	Define.
>>	* testsuite/std/ranges/iota/96042.cc: New test.
>
>The attached patch is another change needed to support __int128 as an
>integer-like type in strict mode.

And one more piece of __int128 support.

Tested x86_64-linux, -m32 and -m64. Committed to trunk.

I'll backport this to gcc-10 too.