xref: /llvm-project/clang-tools-extra/docs/clang-tidy/checks/altera/id-dependent-backward-branch.rst (revision 6e566bc5523f743bc34a7e26f050f1f2b4d699a8)
1.. title:: clang-tidy - altera-id-dependent-backward-branch
2
3altera-id-dependent-backward-branch
4===================================
5
6Finds ID-dependent variables and fields that are used within loops. This causes
7branches to occur inside the loops, and thus leads to performance degradation.
8
9.. code-block:: c++
10
11  // The following code will produce a warning because this ID-dependent
12  // variable is used in a loop condition statement.
13  int ThreadID = get_local_id(0);
14
15  // The following loop will produce a warning because the loop condition
16  // statement depends on an ID-dependent variable.
17  for (int i = 0; i < ThreadID; ++i) {
18    std::cout << i << std::endl;
19  }
20
21  // The following loop will not produce a warning, because the ID-dependent
22  // variable is not used in the loop condition statement.
23  for (int i = 0; i < 100; ++i) {
24    std::cout << ThreadID << std::endl;
25  }
26
27Based on the `Altera SDK for OpenCL: Best Practices Guide
28<https://www.altera.com/en_US/pdfs/literature/hb/opencl-sdk/aocl_optimization_guide.pdf>`_.
29