| Issue |
87466
|
| Summary |
[clang][OpenMP] omp scan code gen does not initialize allocas
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
Dinistro
|
We stumbled over an issue in the code gen for `omp scan`. For a simple example like the following, the "inscan variable" is not properly initialized.
```
int curr_scan = 0;
#pragma omp parallel shared(thread_data, scan, curr_scan)
{
int n = omp_get_num_threads();
#pragma omp for reduction(inscan, + : curr_scan)
for (int i = 0; i < n; ++i) {
scan[i] = curr_scan;
#pragma omp scan exclusive(curr_scan)
curr_scan += thread_data[i];
}
}
```
For a properly initialized `thread_data`, `scan` is filled up with random data.
Looking at the generated IR shows that there are a few basic blocks in the outlined function that are unreachable, which seems suspicious.
Full example w: https://godbolt.org/z/rna6K8T6Y
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