LGTM
On Mon, 14 Oct 2024, Jonathan Wakely wrote:
> Tested x86_64-linux.
>
> -- >8 --
>
> Input iterators aren't required to be copyable.
>
> libstdc++-v3/ChangeLog:
>
> PR libstdc++/117094
> * include/bits/ranges_algobase.h (__fill_fn): Use std::move for
> iterator that might not be copyable.
> * testsuite/25_algorithms/fill/constrained.cc: Check
> non-copyable iterator with sized sentinel.
> ---
> libstdc++-v3/include/bits/ranges_algobase.h | 2 +-
> .../25_algorithms/fill/constrained.cc | 34 +++++++++++++++++++
> 2 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/include/bits/ranges_algobase.h
> b/libstdc++-v3/include/bits/ranges_algobase.h
> index 3c8d46198c5..0345ea850a4 100644
> --- a/libstdc++-v3/include/bits/ranges_algobase.h
> +++ b/libstdc++-v3/include/bits/ranges_algobase.h
> @@ -592,7 +592,7 @@ namespace ranges
> if constexpr (sized_sentinel_for<_Sent, _Out>)
> {
> const auto __len = __last - __first;
> - return ranges::fill_n(__first, __len, __value);
> + return ranges::fill_n(std::move(__first), __len, __value);
> }
> else if constexpr (is_scalar_v<_Tp>)
> {
> diff --git a/libstdc++-v3/testsuite/25_algorithms/fill/constrained.cc
> b/libstdc++-v3/testsuite/25_algorithms/fill/constrained.cc
> index 126515eddca..7cae99f2d5c 100644
> --- a/libstdc++-v3/testsuite/25_algorithms/fill/constrained.cc
> +++ b/libstdc++-v3/testsuite/25_algorithms/fill/constrained.cc
> @@ -83,9 +83,43 @@ test02()
> return ok;
> }
>
> +void
> +test03()
> +{
> + // Bug libstdc++/117094 - ranges::fill misses std::move for output_iterator
> +
> + // Move-only output iterator
> + struct Iterator
> + {
> + using difference_type = long;
> + Iterator(int* p) : p(p) { }
> + Iterator(Iterator&&) = default;
> + Iterator& operator=(Iterator&&) = default;
> + int& operator*() const { return *p; }
> + Iterator& operator++() { ++p; return *this; }
> + Iterator operator++(int) { return Iterator(p++ ); }
> + int* p;
> +
> + struct Sentinel
> + {
> + const int* p;
> + bool operator==(const Iterator& i) const { return p == i.p; }
> + long operator-(const Iterator& i) const { return p - i.p; }
> + };
> +
> + long operator-(Sentinel s) const { return p - s.p; }
> + };
> + static_assert(std::sized_sentinel_for<Iterator::Sentinel, Iterator>);
> + int a[2];
> + std::ranges::fill(Iterator(a), Iterator::Sentinel{a+2}, 999);
> + VERIFY( a[0] == 999 );
> + VERIFY( a[1] == 999 );
> +}
> +
> int
> main()
> {
> test01();
> static_assert(test02());
> + test03();
> }
> --
> 2.46.2
>
>
