BitsCount

A small repository with examples of how one can count set bits in an integer. If you just want to get a gist of different methods of computing the set bits, just navigate to the code folder and look into .cpp files.

A detailed discussion of the algorithms' performance can be found in this post.

Requirements:

• C++20-capable compiler (mainly because of std::popcount function from std, all the rest can be compiled with C++17)
• With AVX512 option: avx512vpopcntdq- and popcnt-capable hardware
• With POPCNT option: popcnt-capable hardware
• CMake ver. >= 3.16

How to build:

Run CMake to generate project files. You can optionally pass the following arguments:

• -DPOPCNT=ON: enables using the popcnt instruction by the compiler
• -DAVX512=ON: enables vectorized popcnt, also enables the usual one (POPCNT flag is not necessary)

---

Tested on x64 processor architecture with

• gcc-10.3.0
• clang-13.0.1
• msvc-19.34.31937.0