Thus can be said about almost all CPU instructions. x64 has tons of SIMD intrinics. You can do absolutely crazy stuff with them if you are willing to invest the time.
True enough, but bitmaps are very easy to use portably, with just &, |, ~, ^, and ++ operations. The only exotic needed very frequently is popcount, but you get that portably from std::bitset (except, evidently, in MSVC).
The compilers are perfectly happy to keep an unsigned and a bitset variable in the same register, so that assigning from one to the other is a no-op.
