Our developments on register allocation with the stm icroelectronics compiler started when Cédric Vincent (bachelor degree, under Alain Darte supervision) developed a complete register allocator in the assembly-code optimizer of stm icroelectronics. This was the first time a complete implementation was done with success, outside the mcdt (now cec ) team, in their optimizer. Since then, new developments are constantly done, in particular by Florent Bouchez, advised by Alain Darte and Fabrice Rastello, as part of his master internship and PhD thesis. The current implementation explores a two-phases register allocation, with a preliminary spilling phase, followed by a coalescing phase (with the help of SSA). See more details in Section 6.3 .