He’s testing on Haswell, where (at least according to Agner Fog) ADC has an extra uop compared to ADD. On Broadwell and later, non-memory ADC is a single uop wi

He’s testing on Haswell, where (at least according to Agner Fog) ADC has an extra uop compared to ADD. On Broadwell and later, non-memory ADC is a single uop with a single cycle of latency. He would probably see a big speedup on a newer CPU.