which usually searches for (executable) commands based on $PATH.

The other related command is locate, which I have given up on due to it consulting stale data, skipping some paths, different implementations, poorly implemented wrapper around it (the worst). When I need to locate a file, I reach for find. locate can die already for all I care.

If gcc is in /use/bin, try searching in /usr/lib: find /usr/lib -name '*gcc_s* (feel free to adjust).