commit c1c3493fb7a3af8efdc50175e592d29e8cb93886
author Victor Stinner <vstinner@python.org> Wed Jan 20 15:20:13 2021 +0100
committer GitHub <noreply@github.com> Wed Jan 20 15:20:13 2021 +0100
tree d389163c67da00b1d6e838cf240311155346b48e
parent 7dc71c425cf6aa6a4070a418dce5d95ca435c79f

bpo-42323: Fix math.nextafter() for NaN on AIX (GH-24265)

Modules/mathmodule.c

diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 86b64fb..8133d6b 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -3473,6 +3473,12 @@
            Bug fixed in bos.adt.libm 7.2.2.0 by APAR IV95512. */
         return PyFloat_FromDouble(y);
     }
+    if (Py_IS_NAN(x)) {
+        return x;
+    }
+    if (Py_IS_NAN(y)) {
+        return y;
+    }
 #endif
     return PyFloat_FromDouble(nextafter(x, y));
 }