CPython: Include/internal/pycore_interp.h

Preallocation of small integers

#define _PY_NSMALLPOSINTS           257
#define _PY_NSMALLNEGINTS           5

…

#if _PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS > 0
    /* Small integers are preallocated in this array so that they
       can be shared.
       The integers that are preallocated are those in the range
       -_PY_NSMALLNEGINTS (inclusive) to _PY_NSMALLPOSINTS (not inclusive).
    */
    PyLongObject* small_ints[_PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS];
#endif