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1.. title:: clang-tidy - altera-single-work-item-barrier2 3altera-single-work-item-barrier4===============================5 6Finds OpenCL kernel functions that call a barrier function but do not call7an ID function (``get_local_id``, ``get_local_id``, ``get_group_id``, or8``get_local_linear_id``).9 10These kernels may be viable single work-item kernels, but will be forced to11execute as NDRange kernels if using a newer version of the Altera Offline12Compiler (>= v17.01).13 14If using an older version of the Altera Offline Compiler, these kernel15functions will be treated as single work-item kernels, which could be16inefficient or lead to errors if NDRange semantics were intended.17 18Based on the `Altera SDK for OpenCL: Best Practices Guide19<https://www.altera.com/en_US/pdfs/literature/hb/opencl-sdk/aocl_optimization_guide.pdf>`_.20 21Examples:22 23.. code-block:: c++24 25 // error: function calls barrier but does not call an ID function.26 void __kernel barrier_no_id(__global int * foo, int size) {27 for (int i = 0; i < 100; i++) {28 foo[i] += 5;29 }30 barrier(CLK_GLOBAL_MEM_FENCE);31 }32 33 // ok: function calls barrier and an ID function.34 void __kernel barrier_with_id(__global int * foo, int size) {35 for (int i = 0; i < 100; i++) {36 int tid = get_global_id(0);37 foo[tid] += 5;38 }39 barrier(CLK_GLOBAL_MEM_FENCE);40 }41 42 // ok with AOC Version 17.01: the reqd_work_group_size turns this into43 // an NDRange.44 __attribute__((reqd_work_group_size(2,2,2)))45 void __kernel barrier_with_id(__global int * foo, int size) {46 for (int i = 0; i < 100; i++) {47 foo[tid] += 5;48 }49 barrier(CLK_GLOBAL_MEM_FENCE);50 }51 52Options53-------54 55.. option:: AOCVersion56 57 Defines the version of the Altera Offline Compiler. Defaults to ``1600``58 (corresponding to version 16.00).59