forked from OSchip/llvm-project
50 lines
1.5 KiB
ReStructuredText
50 lines
1.5 KiB
ReStructuredText
.. title:: clang-tidy - portability-simd-intrinsics
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portability-simd-intrinsics
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===========================
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Finds SIMD intrinsics calls and suggests ``std::experimental::simd`` (`P0214`_)
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alternatives.
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If the option ``Suggest`` is set to non-zero, for
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.. code-block:: c++
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_mm_add_epi32(a, b); // x86
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vec_add(a, b); // Power
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the check suggests an alternative: ``operator+`` on ``std::experimental::simd``
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objects.
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Otherwise, it just complains the intrinsics are non-portable (and there are
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`P0214`_ alternatives).
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Many architectures provide SIMD operations (e.g. x86 SSE/AVX, Power AltiVec/VSX,
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ARM NEON). It is common that SIMD code implementing the same algorithm, is
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written in multiple target-dispatching pieces to optimize for different
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architectures or micro-architectures.
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The C++ standard proposal `P0214`_ and its extensions cover many common SIMD
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operations. By migrating from target-dependent intrinsics to `P0214`_
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operations, the SIMD code can be simplified and pieces for different targets can
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be unified.
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Refer to `P0214`_ for introduction and motivation for the data-parallel standard
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library.
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Options
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-------
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.. option:: Suggest
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If this option is set to non-zero (default is `0`), the check will suggest
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`P0214`_ alternatives, otherwise it only points out the intrinsic function is
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non-portable.
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.. option:: Std
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The namespace used to suggest `P0214`_ alternatives. If not specified, `std::`
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for `-std=c++2a` and `std::experimental::` for `-std=c++11`.
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.. _P0214: https://wg21.link/p0214
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