2 ms·

I think this call for something similar to "__builtin_expect" or linux' likely()/unlikely(). Not very clean, but better than inserting obscure optimisations in

• gblargg 3mo ago
  Assuming compilers are smart enough to insert an unnecessary branch to break the dependency.
  • vitally3643 3mo ago
    That's what the hints are for. Expect/likely/unlikely are the programmer informing the compiler what it should expect and how it should optimize
• purplesyringa 3mo ago
  That would be great, if only it worked as intended! From the perspective of an optimizing compiler, `a == b ? a : b` is worse than `b` regardless of the probability you assign to `a == b`. ETA: someone on Lobsters (https://lobste.rs/s/1an425/quadrupling_code_performance_with#c_4clhdw https://lobste.rs/s/1an425/quadrupling_code_performance_with...) noticed that `[[unlikely]]` actually works on LLVM (not on GCC, and with worse codegen on LLVM, but it's still good to know) -- updated the post.
• MaxBarraclough 3mo ago
  I was wondering the same thing. Also, could profile-guided optimisation help here?