← Back to context Comment by andrepd 10 hours ago This impl is mentioned in TFA.. It's much slower and includes branches. 3 comments andrepd Reply hoten 9 hours ago I'd expect even without optimizations on, there wouldn't be branches in the output for that code. kragen 9 hours ago There are, even with optimizations on. You could have checked: https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename...I didn't find any way to get a compiler to generate a branchless version. I tried clang and GCC, both for amd64, with -O0, -O5, -Os, and for clang, -Oz. mmozeiko 9 hours ago If you change logic and/or to bitwise and/or then it'll be branchless.
hoten 9 hours ago I'd expect even without optimizations on, there wouldn't be branches in the output for that code. kragen 9 hours ago There are, even with optimizations on. You could have checked: https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename...I didn't find any way to get a compiler to generate a branchless version. I tried clang and GCC, both for amd64, with -O0, -O5, -Os, and for clang, -Oz. mmozeiko 9 hours ago If you change logic and/or to bitwise and/or then it'll be branchless.
kragen 9 hours ago There are, even with optimizations on. You could have checked: https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename...I didn't find any way to get a compiler to generate a branchless version. I tried clang and GCC, both for amd64, with -O0, -O5, -Os, and for clang, -Oz. mmozeiko 9 hours ago If you change logic and/or to bitwise and/or then it'll be branchless.
I'd expect even without optimizations on, there wouldn't be branches in the output for that code.
There are, even with optimizations on. You could have checked: https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename...
I didn't find any way to get a compiler to generate a branchless version. I tried clang and GCC, both for amd64, with -O0, -O5, -Os, and for clang, -Oz.
If you change logic and/or to bitwise and/or then it'll be branchless.