BUG: Symbol not found: __powidf2

[bashtage]

Reporting a bug

• I have tried using the latest released version of Numba (most recent is
  visible in the change log (https://github.com/numba/numba/blob/master/CHANGE_LOG).
• I have included below a minimal working reproducer (if you are unsure how
  to write one see http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports).

My CI runs have recently started failing on Windows 32 with Symbol not found: __powidf2

I don't have an easy to to repro other than running the code in my package arch.

Appveyor log is here:

https://ci.appveyor.com/project/bashtage/arch/build/job/f8xl4sqy63jled4t

I wonder if it is related to ldc-developers/ldc#2262

[bashtage]

Pinning to numba<0.50 fixes the problem, so seems to be an error.

The line that was most likely creating the issues in my code is

sigma2[t] += parameters[i + 1] * resids[t - i - 1] ** 2

where all three arguments are double NumPy arrays.

[stuartarchibald]

Thanks for the report, does Numba 0.49 work as expected? If so it's probably LLVM 9 related as it was the first version to work with it, if not it's probably something in the 0.48->0.49 refactor work, I recall removing a lot of windows maths function workarounds when dropping Python 2 for 0.49.

[bashtage]

Yes, rolling back to 0.49 fixed the exception.

The workaround, for now, is to use

sigma2[t] += parameters[i + 1] * (resids[t - i - 1] * resids[t - i - 1])

which lets me support 0.50.

[stuartarchibald]

Thanks for confirming. I'm going to guess it's a LLVM 9 change that we probably need to put in a workaround for.

[jiadongdan]

Hi is it fixed now for the new version of numba?

[esc]

@jiadong93 that is a very good question. The recent released, Numba 0.51.2, depends on llvmlite,m which uses LLVM 10.* for Windows. So it would indeed be interesting to see if this issue still shows up.

[jiadongdan]

@esc , seems ok I have updated to 0.51, my code works fine.

[esc]

@jiadong93 excellent, thanks for checking it out and reporting back. Anyone else to confirm too?

[bashtage]

I'm trying to confim now but am seeing very strange errors on AppVeyor:

C:\Py\lib\site-packages\llvmlite\binding\ffi.py:153: in <module>
    raise OSError("Could not load shared object file: {}".format(_lib_name))
E   OSError: Could not load shared object file: llvmlite.dll
Command exited with code 4

Relevant versions:

llvmlite           pkgs/main/win-64::llvmlite-0.34.0-py38h1a82afc_4
numba              pkgs/main/win-64::numba-0.51.2-py38hf9181ef_1

[esc]

@bashtage thanks for reporting back. May I ask, how you install Numba on your CI system?