GeezerVison

import pyperf

x = 31.4

runner = pyperf.Runner()
runner.bench_func(f"round({x})", round, x, -1)

diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 17e6a729dcd..8342dcbbd16 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -937,11 +936,10 @@ double_round(double x, int ndigits) {
                   buf, decpt - (int)buflen);
 
     /* and convert the resulting string back to a double */
-    errno = 0;
     _Py_SET_53BIT_PRECISION_START;
     rounded = _Py_dg_strtod(mybuf, NULL);
     _Py_SET_53BIT_PRECISION_END;
-    if (errno == ERANGE && fabs(rounded) >= 1.)
+    if (isinf(rounded))
         PyErr_SetString(PyExc_OverflowError,
                         "rounded value too large to represent");
     else