<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/58541>58541</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            OpenMP compilation hang on windows
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          h-vetinari
      </td>
    </tr>
</table>

<pre>
    Sometime between [14.0.4](https://github.com/conda-forge/openmp-feedstock/pull/67) and [14.0.5](https://github.com/conda-forge/openmp-feedstock/pull/68), our openmp recipe stopped working. Since it was a hang in - apparently - some ASM compilation, I thought it might be our infra and didn't raise an issue right away. But it has not gone away for every release since then, and we're still at the same point with 15.0.3, see https://github.com/conda-forge/openmp-feedstock/pull/72.

Our build script is [here](https://github.com/conda-forge/openmp-feedstock/blob/main/recipe/bld-llvm-openmp.bat) and doesn't do much fancy things, and we're compiling with vs2019. Here's a fresh [CI run](https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=593753&view=logs&j=a70f640f-cc53-5cd3-6cdc-236a1aa90802) (old ones get deleted after a month)

The last logs before the hang look something like
```
-- The ASM_MASM compiler identification is MSVC
-- Found assembler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.29.30133/bin/Hostx64/x64/ml64.exe

[...]

[33/39] Building ASM_MASM object runtime\src\CMakeFiles\omp.dir\z_Windows_NT-586_asm.asm.obj

[hangs until killed by infra]
```

or 
```
[33/39] Building CXX object runtime\src\CMakeFiles\omp.dir\kmp_version.cpp.obj

```
</pre>
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