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| author | Patrick Palka <ppalka@redhat.com> | 2021-05-18 00:26:25 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2021-05-18 00:26:25 -0400 |
| commit | 03cf8d54e5c27cfe6b184cc96757cab30d8fa1df (patch) | |
| tree | 88dac99b5e5398864699ab9fa636e72afccd7d0a | |
| parent | 2e2eef80ac0c21f9533e6791ccf5e29458cbb77c (diff) | |
| download | gcc-03cf8d54e5c27cfe6b184cc96757cab30d8fa1df.zip gcc-03cf8d54e5c27cfe6b184cc96757cab30d8fa1df.tar.gz gcc-03cf8d54e5c27cfe6b184cc96757cab30d8fa1df.tar.bz2 | |
libstdc++: Fix condition for memoizing reverse_view::begin() [PR100621]
A range being a random access range isn't a sufficient condition for
ranges::next(iter, sent) to have constant time complexity -- it must
also have a sized sentinel. This adjusts the memoization condition for
reverse_view accordingly.
libstdc++-v3/ChangeLog:
PR libstdc++/100621
* include/std/ranges (reverse_view::_S_needs_cached_begin):
Set to true if the underlying non-common random-access range
doesn't have a sized sentinel.
| -rw-r--r-- | libstdc++-v3/include/std/ranges | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 36bccd6..7079425 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -3228,7 +3228,9 @@ namespace views::__adaptor { private: static constexpr bool _S_needs_cached_begin - = !common_range<_Vp> && !random_access_range<_Vp>; + = !common_range<_Vp> && !(random_access_range<_Vp> + && sized_sentinel_for<sentinel_t<_Vp>, + iterator_t<_Vp>>); [[no_unique_address]] __detail::__maybe_present_t<_S_needs_cached_begin, |