discuss.python.org/t/combining-the-argument-conversion-loops-in-pyeval-vector/109635 Combining the argument-conversion loops in _PyEval_Vector
A proposal to merge the two argument-conversion loops in CPython's _PyEval_Vector into one loop over total_args, removing duplicated code and a second kwnames check while keeping conversion order and reference ownership unchanged. The test suite passes, and the author notes gcc and clang do not fuse the loops themselves, hinting at a small performance gain.
— via Python Discuss, Shamil