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