Branchfree bitmask calculation #895

Job	Run time
windows_mingw64 (windows-latest, Debug)	8m 50s
windows_mingw64 (windows-latest, Release)	3m 17s
linux_128bit	10m 45s
linux_clang (ubuntu-latest, Debug)	5m 56s
linux_clang (ubuntu-latest, Release)	2m 58s
linux_clang_mpopcnt (ubuntu-latest, Debug)	6m 12s
linux_gcc_mpopcnt (ubuntu-latest, Debug)	4m 35s
linux_gcc_sanitizers	3m 5s
linux_clang_mpopcnt (ubuntu-latest, Release)	2m 46s
linux_gcc_mpopcnt (ubuntu-latest, Release)	1m 23s
linux_gcc_valgrind	1m 29s
macos_clang (macos-latest, Debug)	2m 50s
windows_msvc2022	2m 9s
macos_clang (macos-latest, Release)	1m 22s
windows_msvc2022_POPCNT	2m 55s
linux_gcc (ubuntu-latest, Debug)	4m 30s
linux_gcc (ubuntu-latest, Release)	1m 16s
	1h 6m 18s

Provide feedback