BUG: do not emit warnings for np.sign, np.equal when using nan (gh-15230)

* BUG: do not emit warnings for np.sign, np.equal when using nan

* BUG: core: Fix test to handle big-endian platforms.

Co-authored-by: Matti Picus <matti.picus@gmail.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/numpy/core/src/umath/loops.c.src b/numpy/core/src/umath/loops.c.src
index 8a2e5bc40..33d10da49 100644
--- a/numpy/core/src/umath/loops.c.src
+++ b/numpy/core/src/umath/loops.c.src
@@ -1824,6 +1824,7 @@ NPY_NO_EXPORT void
             *((npy_bool *)op1) = in1 @OP@ in2;
         }
     }
+    npy_clear_floatstatus_barrier((char*)dimensions);
 }
 /**end repeat1**/
 
@@ -2068,6 +2069,7 @@ NPY_NO_EXPORT void
         const @type@ in1 = *(@type@ *)ip1;
         *((@type@ *)op1) = in1 > 0 ? 1 : (in1 < 0 ? -1 : (in1 == 0 ? 0 : in1));
     }
+    npy_clear_floatstatus_barrier((char*)dimensions);
 }
 
 NPY_NO_EXPORT void
diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
index 507ac87b9..679bea96a 100644
--- a/numpy/core/tests/test_ufunc.py
+++ b/numpy/core/tests/test_ufunc.py
@@ -1982,3 +1982,21 @@ def test_ufunc_noncontiguous(ufunc):
                 assert_allclose(res_c, res_n, atol=tol, rtol=tol)
             else:
                 assert_equal(c_ar, n_ar)
+
+
+@pytest.mark.parametrize('ufunc', [np.sign, np.equal])
+def test_ufunc_warn_with_nan(ufunc):
+    # issue gh-15127
+    # test that calling certain ufuncs with a non-standard `nan` value does not
+    # emit a warning
+    # `b` holds a 64 bit signaling nan: the most significant bit of the
+    # significand is zero.
+    b = np.array([0x7ff0000000000001], 'i8').view('f8')
+    assert np.isnan(b)
+    if ufunc.nin == 1:
+        ufunc(b)
+    elif ufunc.nin == 2:
+        ufunc(b, b.copy())
+    else:
+        raise ValueError('ufunc with more than 2 inputs')
+