[libcxx-commits] [libcxx] [libc++] Optimize ranges::{for_each, for_each_n} for segmented iterators (PR #132896)

[Louis Dionne via libcxx-commits]

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@@ -76,6 +76,10 @@ Improvements and New Features
 - The ``bitset::to_string`` function has been optimized, resulting in a performance improvement of up to 8.3x for bitsets
   with uniformly distributed zeros and ones, and up to 13.5x and 16.1x for sparse and dense bitsets, respectively.
 
+- The ``std::ranges::for_each`` and ``std::ranges::for_each_n`` algorithms have been optimized for segmented iterators,
+  resulting in performance improvements of up to 21.3x for ``std::deque::iterator`` and 24.9x for ``join_view`` of
+  ``vector<vector<char>>``.
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ldionne wrote:

We should report this optimization on the same line as the `std::for_each` optimization above -- I don't think there is much to be gained from having nearly-duplicate release notes since these algorithms are very similar. While we aim for a good level of completeness in our release notes, we also want to make them as useful to users as possible.

https://github.com/llvm/llvm-project/pull/132896