<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/96698>96698</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [OMPT] Dispatch callback on single-threaded work sharing loops
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          rpereira-dev
      </td>
    </tr>
</table>

<pre>
    ### The issue
LLVM's OpenMP does not raises the `ompt_callback_dispatch_t` callback when running with a single thread in `static` mode

### Standard
The standard 5.2 specifies
> The `ompt_callback_dispatch_t` type is used for callbacks that are dispatched when a thread begins to execute a section or loop iteration.

### Reproducer
```C
int main(void)
{
    # pragma omp parallel for
    for (int i = 0 ; i < 128 ; ++i) {}

    return 0;
}
```

OMPT tool used
```bash
git clone -b llvm/untied-schedule https://github.com/rpereira-dev/ompt-dump.git
```

Compiled and run as
```
clang -Wall -Werror -Wextra -fopenmp main.c
OMP_NUM_THREADS=1 OMP_TOOL_LIBRARIES=path/to/libompt_dump.so ./a.out
```

Outputs
```
[OMPT] [INFO] ompt_callback_thread_begin
[OMPT] [INFO] ompt_callback_implicit_task
[OMPT] [INFO] ompt_callback_parallel_begin
[OMPT] [INFO] ompt_callback_implicit_task
[OMPT] [INFO] ompt_callback_work
[OMPT] [INFO] ompt_callback_work
[OMPT] [INFO] ompt_callback_sync_region
[OMPT] [INFO] ompt_callback_sync_region_wait
[OMPT] [INFO] ompt_callback_sync_region_wait
[OMPT] [INFO] ompt_callback_sync_region
[OMPT] [INFO] ompt_callback_implicit_task
[OMPT] [INFO] ompt_callback_parallel_end
[OMPT] [INFO] ompt_callback_implicit_task
[OMPT] [INFO] ompt_callback_thread_end
```

### Remark
Any other schedule mode triggers the callback properly (even `schedule(runtime)` and `OMP_SCHEDULE=static`) 
</pre>
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