Tiling and memory reuse for sequences of nested loops

International audienceOur aim is to minimize the electrical energy used during the execution of signal processing applications that are a sequence of loop nests. This energy is mostly used to transfer data among various levels of memory hierarchy. To minimize these transfers, we transform these programs by using simultaneously loop permutation, tiling, loop fusion with shifting and memory reuse. Each input nest uses a stencil of data produced in the previous nest and the references to the same array are equal, up to a shift. All transformations described in this paper have been implemented in pips, our optimizing compiler and cache misses reductions have been measured