Fix parallel_for_each with C++20 iterators #1250
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Description
C++20 changed a bit an approach to determine the iterator category - now the new member type
iterator_concept
was introduced and now used as a primary type defining the iterator category. Previousiterator_category
typedef can be defined now into "junior" category (typicallystd::input_iterator_tag
).Also C++20 introduced ranges and used this approach to define iterators for views. E.g
std::ranges::iota_view::iterator
- see here for more details.Currently
parallel_for_each
algorithm uses the "legacy" approach and determines an iterator category based oniterator_category
member type. For modern iterators (e.g.std::ranges::iota_view::iterator
) it will result in using more strict and less efficient implementation for input iterators that implies copying of the entire range.This PR changes the approach to use
std::random_access_iterator
(and other similar) concepts to determine the iterator category that respects bothiterator_concept
anditerator_category
types.We faced similar issue in oneDPL, see issue uxlfoundation/oneDPL#1253 and PR uxlfoundation/oneDPL#1266
Fixes # - issue number(s) if exists
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Tests
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Breaks backward compatibility
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