Register Allocation Using Lazy Saves ,

This paper presents a fast and eeective linear intraprocedu-ral register allocation strategy that optimizes register usage across procedure calls. It capitalizes on our observation that while procedures that do not contain calls (syntactic leaf routines) account for under one third of all procedure activations , procedures that actually make no calls (eeective leaf routines) account for over two thirds of all procedure activations. Well-suited for both caller-and callee-save registers , our strategy employs a \lazy" save mechanism that avoids saves for all eeective leaf routines, an \eager" restore mechanism that reduces the eeect of memory latency, and a \greedy" register shuuing algorithm that does a remarkably good job of minimizing the need for temporaries in setting up procedure calls.