Leaf routine
A leaf routine, leaf subroutine, leaf function, or leaf procedure is a function that does not in turn call another function. Some compilers can apply special program optimizations to leaf routines to make them more efficient, such as the use of link registers to avoid having to push the return address on the stack, or not allocating a register window on CPU architectures descended from Berkeley RISC. The term "leaf" refers to their position as leaf nodes in the call graph of the program.