diff options
| author | Patrick Palka <ppalka@redhat.com> | 2020-02-28 10:47:26 -0500 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2020-02-28 11:55:58 -0500 |
| commit | 77e596cf3c1b7bc11ba946394ed8d62a49157b49 (patch) | |
| tree | 6b6a0525d9558bd1e6a2c1f5b09f83b0e4e5dad0 /libstdc++-v3 | |
| parent | 08bf7bde9f2987b1c623d272cc71fc14a1622442 (diff) | |
libstdc++: Also disable caching of reverse_view::begin() for common_ranges
When the underlying range models common_range, then reverse_view::begin() is
already O(1) without caching. So we should disable the cache in this case too.
libstdc++-v3/ChangeLog:
* include/std/ranges (reverse_view::_S_needs_cached_begin): Set to false
whenever the underlying range models common_range.
Diffstat (limited to 'libstdc++-v3')
| -rw-r--r-- | libstdc++-v3/ChangeLog | 3 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/ranges | 3 |
2 files changed, 5 insertions, 1 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 89e1f5bf952..0feef87cce6 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,8 @@ 2020-02-28 Patrick Palka <ppalka@redhat.com> + * include/std/ranges (reverse_view::_S_needs_cached_begin): Set to false + whenever the underlying range models common_range. + * include/std/ranges (__detail::_CachedPosition): New struct. (views::filter_view::_S_needs_cached_begin): New member variable. (views::filter_view::_M_cached_begin): New member variable. diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 2f773130979..19d3da950e7 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -3177,7 +3177,8 @@ namespace views private: _Vp _M_base = _Vp(); - static constexpr bool _S_needs_cached_begin = !random_access_range<_Vp>; + static constexpr bool _S_needs_cached_begin + = !common_range<_Vp> && !random_access_range<_Vp>; [[no_unique_address]] __detail::__maybe_empty_t<_S_needs_cached_begin, __detail::_CachedPosition<_Vp>> _M_cached_begin; |