Because the function is not quite correct. It should be return n ? (1u + popcoun... | Hacker News

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		pbsd 17 days ago \| parent \| context \| favorite \| on: You can't fool the optimizer Because the function is not quite correct. It should be `return n ? (1u + popcount(n & n - 1u)) : 0u;` which both Clang and GCC promptly optimize to a single popcnt.

1718627440 16 days ago [–]

There should be testsuites, which are based on testing which compilation passes the compiler chose.

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