bpo-29882: Add _Py_popcount32() function (GH-20518)

* Rename pycore_byteswap.h to pycore_bitutils.h.
* Move popcount_digit() to pycore_bitutils.h as _Py_popcount32().
* _Py_popcount32() uses GCC and clang builtin function if available.
* Add unit tests to _Py_popcount32().

Victor Stinner committed 5y ago

c6b292cdeee689f0bfac6c1e2c2d4e4e01fa8d9e

Parent: 301f0d4

Committed by GitHub <noreply@github.com> on 6/8/2020, 2:30:33 PM