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BUG: exp on macOS fails tests #13586
Description
@tylerjereddy reports the following test failure output from the latest master branch commit (8a421d9) when running full test suite on a Mac laptop:
@r-devulap, @juliantaylor - any thoughts?
Details
________________________ TestSpecialFloats.test_exp_values _________________________
[gw1] darwin -- Python 3.6.5 /Users/treddy/miniconda3/envs/numpy_dev_py36/bin/python
self = <numpy.core.tests.test_umath.TestSpecialFloats object at 0x11bccdac8>
def test_exp_values(self):
x = [np.nan, np.nan, np.inf, 0.]
y = [np.nan, -np.nan, np.inf, -np.inf]
for dt in ['f', 'd', 'g']:
xf = np.array(x, dtype=dt)
yf = np.array(y, dtype=dt)
> assert_equal(np.exp(yf), xf)
E RuntimeWarning: invalid value encountered in exp
dt = 'f'
self = <numpy.core.tests.test_umath.TestSpecialFloats object at 0x11bccdac8>
x = [nan, nan, inf, 0.0]
xf = array([nan, nan, inf, 0.], dtype=float32)
y = [nan, nan, inf, -inf]
yf = array([ nan, nan, inf, -inf], dtype=float32)
numpy/core/tests/test_umath.py:659: RuntimeWarning
1 failed, 8641 passed, 63 skipped, 15 xfailed, 3 xpassed in 120.79 seconds
Activity
r-devulap commentedon May 19, 2019
I was able to reproduce this on my SKX, but only when built with clang7.0 (it passes when run with gcc7 and clang6.0). I will debug later today to see where it's coming from ..
r-devulap commentedon May 19, 2019
This is the instruction that is raising invalid exception:
xmin_mask = _mm256_cmp_ps(x, _mm256_set1_ps(xmin), _CMP_LE_OQ);whenxis anan. Not sure whats special with clang7.0mattip commentedon May 19, 2019
maybe a bug in clang?
r-devulap commentedon May 19, 2019
probably,
_CMP_LE_OQis supposed to non-signaling and as far as I understand that shouldn't set a floating point exception.r-devulap commentedon May 19, 2019
Yeah I think this is a clang7 behavior which seems incorrect. I wrote a small test case to confirm this:
With gcc and clang6.0:
with clang7.0, it sets the invalid bit which I think is incorrect.
r-devulap commentedon May 19, 2019
This test
test_exp_valuesonly cares about the value of the output, I think it might be okay to disable FPE exceptions just for this test with withnp.errstate(all='ignore'):mattip commentedon May 19, 2019
@charris: We have a mechanism for whitelist/blacklisting compiler bugs, how does it work?
charris commentedon May 19, 2019
@mattip We have a mechanism for library math functions, but this looks like a constant macro which is probably used to direct a compilation path. If we can detect it during configuration and have a fall back function we can fix it, but I'm not sure what the fallback function would be.
charris commentedon May 19, 2019
_CMP_LE_OQI wonder what the actual value of this macro is? We could possibly detect/fix that, but it might be architecture dependent.r-devulap commentedon May 20, 2019
Its 18 and I think it should be the same across x86 architecture. See https://software.intel.com/sites/landingpage/IntrinsicsGuide/#expand=3004,3045,3005,2822,737&text=cmp_ps
r-devulap commentedon May 28, 2019
perhaps this and issue #13400 can be closed now?
tylerjereddy commentedon May 29, 2019
I can definitely close this because I confirmed the fix this morning.
Perhaps Julian should close the other, though it looks connected at a quick glance.
tylerjereddy commentedon May 29, 2019
Thanks @r-devulap