[antonwolfy]

DPC++ 2026.0 is the minimum compiler (the conda recipes reject anything older), and every 2026.x release ships libsycl 9 (__LIBSYCL_MAJOR_VERSION 9). Two __LIBSYCL_MAJOR_VERSION checks in the libtensor headers therefore always take the same branch.

This PR:

• drops the __LIBSYCL_MAJOR_VERSION < 7 term from needs_workaround in kernels/reductions.hpp, which kept sycl::logical_or<bool> off reduce-over-group for older compilers. The term is always false; the int64/uint64 sycl::multiplies exclusion stays.
• removes USE_GROUP_LOAD_STORE from utils/sycl_utils.hpp, so sub_group_load and sub_group_store always use group_load/group_store from sycl_ext_oneapi_group_load_store. The __LIBSYCL_MAJOR_VERSION >= 8u check already set the macro to 1 (DPC++ 2026.0 doesn't define the SYCL_EXT_ONEAPI_GROUP_LOAD_STORE feature-test macro the check looked at first). Setting it to 0 by hand doesn't work either: the fallback calls the sycl::sub_group member load/store, and icpx 2026.0 fails with no member named 'load' in 'sycl::sub_group'. The macro is defined in a header shipped with dpnp, hence the changelog entry.

The default build compiles the same code as before. With icpx 2026.2, a syntax-only compile of both headers passes without warnings, and static asserts confirm that needs_workaround and can_use_reduce_over_group keep their values for logical_or<bool> and for the int64/uint64 multiplies.

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to an issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• Have you added documentation for your changes, if necessary?
• Have you added your changes to the changelog?

[github-actions]

Array API standard conformance tests for dpnp=0.22.0dev1=np2py314h8d9cdd5_8 ran successfully.
Passed: 1491
Failed: 0
Skipped: 6

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/index.html

[ndgrigorian]

Tests pass, LGTM

[coveralls]

coverage: 84.404% (+0.007%) from 84.397% — drop-dead-libsycl-version-checks into master

[Copilot]

🟢 Approval recommended

No active review issues block the removal of obsolete libsycl compatibility branches.

No open issues 🎉

What changed in this PR

Removes obsolete libsycl compatibility branches from libtensor headers now that DPC++ 2026.0 is the minimum supported compiler, preserving the default build behavior.

Changes:

• Makes subgroup loads and stores always use the group-load/store extension.
• Removes the legacy boolean logical-or reduction workaround while retaining the 64-bit multiplication exclusion.
• Documents removal of the shipped USE_GROUP_LOAD_STORE macro.

File	Description
dpnp/​libtensor/​include/​utils/​sycl_utils.hpp	Removes the load/store selection macro and legacy fallback paths.
dpnp/​libtensor/​include/​kernels/​reductions.hpp	Simplifies reduction workaround selection by dropping the obsolete version check.
CHANGELOG.md	Records the macro removal and compiler compatibility rationale.

_{Review effort: Balanced}