TEST: Mark linspace subnormal test as xfail on ARM32 platforms

Adds an xfail marker to the linspace subnormal test case for ARMv7 and AArch32 platforms. These platforms seem to flush subnormals to zero (FTZ) even when not explicitly enabled via the FPSCR register, causing the test to fail.
numpy · charris · Apr 6, 2025 · Apr 5, 2025 · Apr 5, 2025 · Apr 5, 2025
commit a3828f14fd0b6f9c26b21e442ab9a45f0bcdb3b6
diff --git a/numpy/_core/tests/test_function_base.py b/numpy/_core/tests/test_function_base.py
@@ -1,5 +1,5 @@
 import sys
-
+import platform
 import pytest

 import numpy as np
@@ -14,6 +14,9 @@
    IS_PYPY
    )

+def _is_armhf():
+    # Check if the current platform is ARMHF (32-bit ARM architecture)
+    return platform.machine().startswith('arm') and platform.architecture()[0] == '32bit'

 class PhysicalQuantity(float):
    def __new__(cls, value):
@@ -414,6 +417,9 @@ def __mul__(self, other):

        assert_equal(linspace(one, five), linspace(1, 5))

+    # even when not explicitly enabled via FPSCR register
+    @pytest.mark.xfail(_is_armhf(),
+                       reason="ARMHF/AArch32 platforms seem to FTZ subnormals")
    def test_denormal_numbers(self):
        # Regression test for gh-5437. Will probably fail when compiled
        # with ICC, which flushes denormals to zero