From the gcc manual: 'noinline - This function attribute prevents a
function from being considered for inlining. If the function does not
have side effects, there are optimizations other than inlining that
cause function calls to be optimized away, although the function call is
live. To keep such calls from being optimized away, put asm ("");'
(https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html)