ValueError for `math.atan2(0.0, 0.0)` and `cmath.phase(0.0)` using icx

Bug report

Bug description:

The math function atan2 and the cmath function phase should not raise ValueError when their arguments are zero. This is true when building CPython using an officially supported compiler such as GCC:

>>> import math
>>> import cmath
>>> math.atan2(0.0, 0.0)
0.0
>>> cmath.phase(complex(0.0, 0.0))
0.0
>>> math.atan2(0.0, -0.0)
3.141592653589793
>>> cmath.phase(complex(-0.0, 0.0))
3.141592653589793

However, The C23 standard (ISO/IEC 9899:2024) in section 7.12.4.4 for atan2 states:

A domain error may occur if both arguments are zero.

The Intel math library version 2026.0.0 sets errno to EDOM for these cases. See also PR #152825. Thus:

>>> import math
>>> import cmath
>>> math.atan2(0.0, 0.0)
Traceback (most recent call last):
  File "<python-input-2>", line 1, in <module>
    math.atan2(0.0, 0.0)
    ~~~~~~~~~~^^^^^^^^^^
ValueError: math domain error
>>> cmath.phase(complex(0.0, 0.0))
Traceback (most recent call last):
  File "<python-input-3>", line 1, in <module>
    cmath.phase(complex(0.0, 0.0))
    ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
ValueError: math domain error
>>> math.atan2(0.0, -0.0)
Traceback (most recent call last):
  File "<python-input-4>", line 1, in <module>
    math.atan2(0.0, -0.0)
    ~~~~~~~~~~^^^^^^^^^^^
ValueError: math domain error
>>> cmath.phase(complex(-0.0, 0.0))
Traceback (most recent call last):
  File "<python-input-5>", line 1, in <module>
    cmath.phase(complex(-0.0, 0.0))
    ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
ValueError: math domain error

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-153148

Revisa primero el PR #152825 y el PR #153148 enlazado, ya que parecen abordar este informe. Empieza rastreando las implementaciones de CPython de math.atan2 y cmath.phase y comparando el comportamiento con icx frente a GCC. Se considera terminado cuando los argumentos con valor cero ya no generan ValueError y conservan los resultados documentados de signed-zero.