# Extra Clang Tools 18.1.8 documentation

## clang-tidy - altera-id-dependent-backward-branch

# altera-id-dependent-backward-branch

Finds ID-dependent variables and fields that are used within loops. This causes branches to occur inside the loops, and thus leads to performance degradation.

    // The following code will produce a warning because this ID-dependent
    // variable is used in a loop condition statement.
    int ThreadID = get_local_id(0);

    // The following loop will produce a warning because the loop condition
    // statement depends on an ID-dependent variable.
    for (int i = 0; i < ThreadID; ++i) {
      std::cout << i << std::endl;
    }

    // The following loop will not produce a warning, because the ID-dependent
    // variable is not used in the loop condition statement.
    for (int i = 0; i < 100; ++i) {
      std::cout << ThreadID << std::endl;
    }

Based on the Altera SDK for OpenCL: Best Practices Guide.