Collection of interesting c++-related stuff (optimizations, lack of optimizations, benchmarks, etc.):

• Returning bool from predicate may prevent std::count_if auto-vectorization;
• When anticipating auto-vectorization, beware of type mismatches
  • More improvements with __builtin_unreachable() and std::assume_aligned.

• For local benchmark outputs, if not otherwise specified, the CPU used is Intel(R) Core(TM) i5-8265U.