A scheduler-sensitive global register allocator

Abstract

Compile-time reordering of machine-level instructions has been very successful at achieving large increases in performance of programs on machines offering fine-grained parallelism. However, because of the interdependences between instruction scheduling and register allocation, it is not clear which of these two phases of the compiler should run first to generate the most efficient final code. The authors describe their investigation into slight modifications to key phases of a successful global register allocator to create a scheduler-sensitive register allocator, which is then followed by an off-the-shelf instruction scheduler. These experimental studies reveal that this approach achieves speedups comparable and increasingly better than previous cooperative approaches with an increasing number of available registers without the complexities of the previous approaches.