From: Patrick Palka Date: Tue, 26 Aug 2025 19:45:57 +0000 (-0400) Subject: libstdc++/ranges: Prefer using offset-based _CachedPosition X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06e627e1e246e423bf2af754f9a1401cf6ae3c99;p=thirdparty%2Fgcc.git libstdc++/ranges: Prefer using offset-based _CachedPosition The offset-based partial specialization of _CachedPosition for random-access iterators is currently only selected if the offset type is smaller than the iterator type. Before r12-1018-g46ed811bcb4b86 this made sense since the main partial specialization only stored the iterator (incorrectly). After that bugfix, the main partial specialization now effectively stores a std::optional so the size constraint is inaccurate. And this main partial specialization must invalidate itself upon copy/move unlike the offset-based partial specialization. So I think we should just always prefer the offset-based _CachedPosition for a random-access iterator, even if the offset type happens to be larger than the iterator type. libstdc++-v3/ChangeLog: * include/std/ranges (__detail::_CachedPosition): Remove additional size constraint on the offset-based partial specialization. Reviewed-by: Tomasz Kamiński Reviewed-by: Jonathan Wakely --- diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index efe62969d65..2970b2cbe00 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -1585,8 +1585,6 @@ namespace views::__adaptor }; template - requires (sizeof(range_difference_t<_Range>) - <= sizeof(iterator_t<_Range>)) struct _CachedPosition<_Range> { private: