diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index df3aedec6eeab5..12234e254e1a7a 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -4273,11 +4273,10 @@ Array_subscript(PyObject *myself, PyObject *item)
         PyObject *np;
         Py_ssize_t start, stop, step, slicelen, cur, i;
 
-        if (PySlice_GetIndicesEx(item,
-                                 self->b_length, &start, &stop,
-                                 &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelen = PySlice_AdjustIndices(self->b_length, &start, &stop, step);
 
         stgdict = PyObject_stgdict((PyObject *)self);
         assert(stgdict); /* Cannot be NULL for array object instances */
@@ -4414,11 +4413,10 @@ Array_ass_subscript(PyObject *myself, PyObject *item, PyObject *value)
     else if (PySlice_Check(item)) {
         Py_ssize_t start, stop, step, slicelen, otherlen, i, cur;
 
-        if (PySlice_GetIndicesEx(item,
-                                 self->b_length, &start, &stop,
-                                 &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelen = PySlice_AdjustIndices(self->b_length, &start, &stop, step);
         if ((step < 0 && start < stop) ||
             (step > 0 && start > stop))
             stop = start;
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index e3350d194da18a..bef702ebe69c93 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -1712,11 +1712,11 @@ element_subscr(PyObject* self_, PyObject* item)
         if (!self->extra)
             return PyList_New(0);
 
-        if (PySlice_GetIndicesEx(item,
-                self->extra->length,
-                &start, &stop, &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelen = PySlice_AdjustIndices(self->extra->length, &start, &stop,
+                                         step);
 
         if (slicelen <= 0)
             return PyList_New(0);
@@ -1768,11 +1768,11 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
                 return -1;
         }
 
-        if (PySlice_GetIndicesEx(item,
-                self->extra->length,
-                &start, &stop, &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelen = PySlice_AdjustIndices(self->extra->length, &start, &stop,
+                                         step);
 
         if (value == NULL) {
             /* Delete slice */
diff --git a/Modules/_testbuffer.c b/Modules/_testbuffer.c
index 4e1ce6851a5eb6..6b8ab34d931cd3 100644
--- a/Modules/_testbuffer.c
+++ b/Modules/_testbuffer.c
@@ -1715,10 +1715,10 @@ init_slice(Py_buffer *base, PyObject *key, int dim)
 {
     Py_ssize_t start, stop, step, slicelength;
 
-    if (PySlice_GetIndicesEx(key, base->shape[dim],
-                             &start, &stop, &step, &slicelength) < 0) {
+    if (PySlice_Unpack(key, &start, &stop, &step) < 0) {
         return -1;
     }
+    slicelength = PySlice_AdjustIndices(base->shape[dim], &start, &stop, step);
 
 
     if (base->suboffsets == NULL || dim == 0) {
@@ -1935,9 +1935,10 @@ slice_indices(PyObject *self, PyObject *args)
             "first argument must be a slice object");
         return NULL;
     }
-    if (PySlice_GetIndicesEx(key, len, &s[0], &s[1], &s[2], &s[3]) < 0) {
+    if (PySlice_Unpack(key, &s[0], &s[1], &s[2]) < 0) {
         return NULL;
     }
+    s[3] = PySlice_AdjustIndices(len, &s[0], &s[1], s[2]);
 
     ret = PyTuple_New(4);
     if (ret == NULL)
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index d4221fe4c6a163..64e0f172fd7d82 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -2297,10 +2297,11 @@ array_subscr(arrayobject* self, PyObject* item)
         arrayobject* ar;
         int itemsize = self->ob_descr->itemsize;
 
-        if (PySlice_GetIndicesEx(item, Py_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
 
         if (slicelength <= 0) {
             return newarrayobject(&Arraytype, 0, self->ob_descr);
@@ -2368,11 +2369,11 @@ array_ass_subscr(arrayobject* self, PyObject* item, PyObject* value)
             return (*self->ob_descr->setitem)(self, i, value);
     }
     else if (PySlice_Check(item)) {
-        if (PySlice_GetIndicesEx(item,
-                                 Py_SIZE(self), &start, &stop,
-                                 &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
     }
     else {
         PyErr_SetString(PyExc_TypeError,
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 5f1615ff82992c..426b7cacebb573 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -806,10 +806,10 @@ mmap_subscript(mmap_object *self, PyObject *item)
     else if (PySlice_Check(item)) {
         Py_ssize_t start, stop, step, slicelen;
 
-        if (PySlice_GetIndicesEx(item, self->size,
-                         &start, &stop, &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelen = PySlice_AdjustIndices(self->size, &start, &stop, step);
 
         if (slicelen <= 0)
             return PyBytes_FromStringAndSize("", 0);
@@ -932,11 +932,10 @@ mmap_ass_subscript(mmap_object *self, PyObject *item, PyObject *value)
         Py_ssize_t start, stop, step, slicelen;
         Py_buffer vbuf;
 
-        if (PySlice_GetIndicesEx(item,
-                                 self->size, &start, &stop,
-                                 &step, &slicelen) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelen = PySlice_AdjustIndices(self->size, &start, &stop, step);
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError,
                 "mmap object doesn't support slice deletion");
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index d456678d462f2f..a9c8ca6f1f35a8 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -400,11 +400,11 @@ bytearray_subscript(PyByteArrayObject *self, PyObject *index)
     }
     else if (PySlice_Check(index)) {
         Py_ssize_t start, stop, step, slicelength, cur, i;
-        if (PySlice_GetIndicesEx(index,
-                                 PyByteArray_GET_SIZE(self),
-                                 &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(index, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(PyByteArray_GET_SIZE(self),
+                                            &start, &stop, step);
 
         if (slicelength <= 0)
             return PyByteArray_FromStringAndSize("", 0);
@@ -630,11 +630,11 @@ bytearray_ass_subscript(PyByteArrayObject *self, PyObject *index, PyObject *valu
         }
     }
     else if (PySlice_Check(index)) {
-        if (PySlice_GetIndicesEx(index,
-                                 PyByteArray_GET_SIZE(self),
-                                 &start, &stop, &step, &slicelen) < 0) {
+        if (PySlice_Unpack(index, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelen = PySlice_AdjustIndices(PyByteArray_GET_SIZE(self), &start,
+                                         &stop, step);
     }
     else {
         PyErr_Format(PyExc_TypeError,
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index c95a46d1846649..4c55294d9d8c8a 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -1683,11 +1683,11 @@ bytes_subscript(PyBytesObject* self, PyObject* item)
         char* result_buf;
         PyObject* result;
 
-        if (PySlice_GetIndicesEx(item,
-                         PyBytes_GET_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(PyBytes_GET_SIZE(self), &start,
+                                            &stop, step);
 
         if (slicelength <= 0) {
             return PyBytes_FromStringAndSize("", 0);
diff --git a/Objects/listobject.c b/Objects/listobject.c
index cde281a0f6f9dc..547bdf0b95f1ee 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2420,10 +2420,11 @@ list_subscript(PyListObject* self, PyObject* item)
         PyObject* it;
         PyObject **src, **dest;
 
-        if (PySlice_GetIndicesEx(item, Py_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
 
         if (slicelength <= 0) {
             return PyList_New(0);
@@ -2469,10 +2470,11 @@ list_ass_subscript(PyListObject* self, PyObject* item, PyObject* value)
     else if (PySlice_Check(item)) {
         Py_ssize_t start, stop, step, slicelength;
 
-        if (PySlice_GetIndicesEx(item, Py_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
 
         if (step == 1)
             return list_ass_slice(self, start, stop, value);
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index b1798a2073d108..e1ac7281783f38 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -2285,10 +2285,10 @@ init_slice(Py_buffer *base, PyObject *key, int dim)
 {
     Py_ssize_t start, stop, step, slicelength;
 
-    if (PySlice_GetIndicesEx(key, base->shape[dim],
-                             &start, &stop, &step, &slicelength) < 0) {
+    if (PySlice_Unpack(key, &start, &stop, &step) < 0) {
         return -1;
     }
+    slicelength = PySlice_AdjustIndices(base->shape[dim], &start, &stop, step);
 
 
     if (base->suboffsets == NULL || dim == 0) {
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 52f20f4fe8a2b1..0dada74dc7c986 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -720,11 +720,11 @@ tuplesubscript(PyTupleObject* self, PyObject* item)
         PyObject* it;
         PyObject **src, **dest;
 
-        if (PySlice_GetIndicesEx(item,
-                         PyTuple_GET_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(PyTuple_GET_SIZE(self), &start,
+                                            &stop, step);
 
         if (slicelength <= 0) {
             return PyTuple_New(0);
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index a5ae454b495dee..949205adf9347e 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -13915,10 +13915,11 @@ unicode_subscript(PyObject* self, PyObject* item)
         int src_kind, dest_kind;
         Py_UCS4 ch, max_char, kind_limit;
 
-        if (PySlice_GetIndicesEx(item, PyUnicode_GET_LENGTH(self),
-                                 &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(PyUnicode_GET_LENGTH(self),
+                                            &start, &stop, step);
 
         if (slicelength <= 0) {
             _Py_RETURN_UNICODE_EMPTY();