hardware_destructive_interference_size definition that handles compilers that don't support std::hardware_destructive_interference_size

hardware_destructive_interference_size.hpp

constexpr size_t hardware_destructive_interference_size = []() -> size_t {
#ifdef __cpp_lib_hardware_interference_size
  return std::hardware_destructive_interference_size;
#endif

  // The following values were taken from those commonly used in Google
  // open source projects as defined with their CACHELINE_SIZE macro

#if defined(__i386__) || defined(__x86_64__)
  return 64;
#endif

#ifdef __powerpc64__
  return 128;
#endif

  // ARM cache line sizes vary depending on implementation, but these are
  // reasonable defaults

#ifdef __ARM_ARCH_5T__
  return 32;
#endif

#ifdef __ARM_ARCH_7A__
  return 64;
#endif

  // Fallback to a reasonable default for undefined architectures

  return 64;
}();