4 ms·

Does false dependency count as bug?

• vardump 4y ago
  Kinda. Not like it'd produce a wrong result, but you could say it's a bug (presumably) in the out-of-order scheduler.
  • kevincox 4y ago
    Exactly: It's a performance bug not a correctness bug.
• DannyBee 4y ago
  Intel will list them as errata if you beat them up enough. They rarely fix them. POPCNT false dependency on sky lake was never fixed, we just ended up with compilers inserting useless xor's before popcnt to break dependencies.