I have some code that uses gcc intrinsics. I would like to include code in case the intrinsic is missing. How can I do this?
#ifdef __builtin_ctzll
does not work.
GCC now (for the last few years) supports __has_builtin: It was introduced in GCC 10.1, May 7 2020. See the new features for that version here.
Also, thanks to @Charles comment, find the bug report here