Fix compile error in `inclusive_scan` and `exclusive_scan` over reverse iterators with different source iterator types #2371

SergeyKopienko · 2025-08-05T14:12:14Z

This PR fixes a compile error in oneDPL's inclusive_scan and exclusive_scan operations when used with reverse iterators that have different source iterator types (issue #2296). The solution enhances iterator equality comparison by implementing sophisticated logic to unwrap base iterators (from std::reverse_iterator only) and compare them instead of comparing adapter iterators directly.

Enhanced iterator equality comparison with C++20 concepts support and fallback implementation for complex iterator types
Added comprehensive test coverage for reverse iterator scenarios with type conversion in exclusive_scan
Removed problematic assertions in USM data transfer utilities that were incompatible with iterator arithmetic

include/oneapi/dpl/pstl/utils.h

…s.cpp - remove empty test

…s.cpp - additional test case^ two iterators from the different containers

…s.cpp - remove test_is_iterator_type()

test/general/implementation_details/test_sycl_iterator_operations.pass.cpp

include/oneapi/dpl/pstl/utils.h

- to prevent the assertion from Microsoft STL implementation about the comparison of iterators from different containers

…quality_comparable_with - extract is_equality_comparable_with_impl

…ype_with_iterator_traits

…r __is_type_with_iterator_traits" This reverts commit c49fcda.

…r __is_equality_comparable_with" This reverts commit 0f0d4ed.

This reverts commit 7b85e8f.

…th_impl

danhoeflinger

This LGTM now

…s.cpp - fix review comment: additional tests

danhoeflinger

thanks for the testing changes. LGTM

SergeyKopienko added the bug label Aug 5, 2025

SergeyKopienko added this to the 2022.10.0 milestone Aug 5, 2025

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SergeyKopienko force-pushed the dev/skopienko/fix_iterators_comparison_V01 branch from 9b2bb00 to ed58f9c Compare August 5, 2025 14:22

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SergeyKopienko assigned danhoeflinger and unassigned danhoeflinger Aug 5, 2025

SergeyKopienko requested review from danhoeflinger and MikeDvorskiy August 5, 2025 14:23

SergeyKopienko mentioned this pull request Aug 5, 2025

Fix compile error in inclusive_scan and exclusive_scan over reverse iterators with different source iterator types #2359

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SergeyKopienko linked an issue Aug 5, 2025 that may be closed by this pull request

inclusive_scan and exclusive_scan over reverse iterators with different source iterator types fails to compile #2296

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SergeyKopienko force-pushed the dev/skopienko/fix_iterators_comparison_V01 branch from ed58f9c to 828248b Compare August 5, 2025 14:28

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SergeyKopienko removed request for akukanov, MikeDvorskiy, mmichel11 and danhoeflinger August 5, 2025 14:49

SergeyKopienko marked this pull request as draft August 5, 2025 14:49

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SergeyKopienko force-pushed the dev/skopienko/fix_iterators_comparison_V01 branch from cfaabd7 to f8bfd76 Compare August 6, 2025 13:00

SergeyKopienko commented Aug 6, 2025

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include/oneapi/dpl/pstl/utils.h Outdated Show resolved Hide resolved

SergeyKopienko force-pushed the dev/skopienko/fix_iterators_comparison_V01 branch from f8bfd76 to a79429a Compare August 6, 2025 13:23

test/general/implementation_details/test_sycl_iterator_operations.pas…

c546a83

…s.cpp - remove empty test

SergeyKopienko requested a review from danhoeflinger August 12, 2025 16:33

SergeyKopienko added 6 commits August 12, 2025 18:34

Apply GitHUB clang format

9ac686d

test/general/implementation_details/test_sycl_iterator_operations.pas…

3b92554

…s.cpp - additional test case^ two iterators from the different containers

Merge branch 'main' into dev/skopienko/fix_iterators_comparison_V01

2b13d89

Merge branch 'main' into dev/skopienko/fix_iterators_comparison_V01

d86f4cf

test/general/implementation_details/test_sycl_iterator_operations.pas…

ba0007a

…s.cpp - remove test_is_iterator_type()

Merge branch 'main' into dev/skopienko/fix_iterators_comparison_V01

38127cf

danhoeflinger reviewed Aug 13, 2025

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test/general/implementation_details/test_sycl_iterator_operations.pass.cpp Show resolved Hide resolved

rarutyun reviewed Aug 13, 2025

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SergeyKopienko added 5 commits August 14, 2025 09:13

Merge branch 'main' into dev/skopienko/fix_iterators_comparison_V01

9422b8a

Introduce new _PSTL_TEST_ITERATORS_POSSIBLY_EQUAL_BROKEN

e916797

- to prevent the assertion from Microsoft STL implementation about the comparison of iterators from different containers

include/oneapi/dpl/pstl/utils.h - introduce __clean_iterator_t

7b85e8f

include/oneapi/dpl/pstl/utils.h - apply __clean_iterator_t for __is_e…

0f0d4ed

…quality_comparable_with - extract is_equality_comparable_with_impl

include/oneapi/dpl/pstl/utils.h - apply __clean_iterator_t for __is_t…

c49fcda

…ype_with_iterator_traits

SergeyKopienko requested review from danhoeflinger and rarutyun August 14, 2025 07:49

SergeyKopienko added 4 commits August 14, 2025 10:24

Revert "include/oneapi/dpl/pstl/utils.h - apply __clean_iterator_t fo…

3ad9413

…r __is_type_with_iterator_traits" This reverts commit c49fcda.

Revert "include/oneapi/dpl/pstl/utils.h - apply __clean_iterator_t fo…

b8b23c1

…r __is_equality_comparable_with" This reverts commit 0f0d4ed.

Revert "include/oneapi/dpl/pstl/utils.h - introduce __clean_iterator_t"

4252763

This reverts commit 7b85e8f.

include/oneapi/dpl/pstl/utils.h - extract __is_equality_comparable_wi…

e6b513f

…th_impl

danhoeflinger previously approved these changes Aug 14, 2025

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SergeyKopienko dismissed danhoeflinger’s stale review via 4310358 August 19, 2025 09:40

SergeyKopienko requested a review from danhoeflinger August 19, 2025 09:40

test/general/implementation_details/test_sycl_iterator_operations.pas…

24c92fe

…s.cpp - fix review comment: additional tests

SergeyKopienko force-pushed the dev/skopienko/fix_iterators_comparison_V01 branch from 4310358 to 24c92fe Compare August 19, 2025 09:42

danhoeflinger approved these changes Aug 19, 2025

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SergeyKopienko merged commit 68433ed into main Aug 19, 2025
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SergeyKopienko deleted the dev/skopienko/fix_iterators_comparison_V01 branch August 19, 2025 12:26

SergeyKopienko mentioned this pull request Aug 19, 2025

inclusive_scan and exclusive_scan over reverse iterators with different source iterator types fails to compile #2296

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Fix compile error in `inclusive_scan` and `exclusive_scan` over reverse iterators with different source iterator types #2371

Fix compile error in `inclusive_scan` and `exclusive_scan` over reverse iterators with different source iterator types #2371

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Fix compile error in inclusive_scan and exclusive_scan over reverse iterators with different source iterator types #2371

Fix compile error in inclusive_scan and exclusive_scan over reverse iterators with different source iterator types #2371

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Fix compile error in `inclusive_scan` and `exclusive_scan` over reverse iterators with different source iterator types #2371

Fix compile error in `inclusive_scan` and `exclusive_scan` over reverse iterators with different source iterator types #2371

SergeyKopienko commented Aug 5, 2025 •

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