Section: Overall Objectives

Introduction

Keywords:

Compilation, code analysis, code optimization, memory optimization, combinatorial optimization, algorithmics, polyhedral optimization, hardware accelerators, high-level synthesis, high-performance computing.

The objective of Compsys is to adapt and to extend code analysis and code optimization techniques primarily designed in compilers/parallelizers for high performance computing to the special case of embedded computing systems. In particular, Compsys works on back-end optimizations for specialized processors and on high-level program transformations, in particular for the compilation towards or the synthesis of hardware accelerators. The main characteristic of Compsys is its focus on combinatorial problems (graph algorithms, linear programming, polyhedra) coming from code optimizations (register allocation, cache and memory optimizations, scheduling, optimizations for power, automatic generation of software/hardware interfaces, etc.) and the validation of techniques developed in compilation tools.

Compsys started as an Inria project in 2004, after 2 years of maturation. This first period of Compsys, Compsys I, was positively evaluated in Spring 2007 after its first 4 years period (2004-2007). It was again evaluated by AERES in 2009, as part of the general evaluation of Lip, and got the best possible mark, A+. The second period (2007-2012), Compsys II, was again evaluated positively by Inria in Spring 2012 and formally prolongated into Compsys III at the very end of 2012. The geographical move in 2013 of Fabrice Rastello to Grenoble was first to expand the activities of Compsys in the context of Giant, a R&D technology center with several industrial and academic actors. In 2014, this geographical move is a departure from Compsys, Fabrice Rastello will now work on his own. The research directions of Compsys III are nevertheless not modified drastically and are in line with the research directions presented in the synthesis report provided for the 2012 evaluation  (See http://www.ens-lyon.fr/LIP/COMPSYS/wordpress/wp-content/uploads/2013/09/ficheSynthese.pdf ). The shift towards dynamic compilation, underlined in this report, will be pursued by Fabrice Rastello only, while the shift towards the compilation of streaming programming, the analysis and optimizations of parallel languages, with an even stronger focus on polyhedral optimizations are the heart of Compsys III, as well as the development of the Zettice start-up in which Christophe Alias is involved. The hiring of Laure Gonnord also adds new forces on the code analysis research aspects.

Section  2.2 defines the general context of the team's activities. Section  2.3 presents the research objectives and main achievements in Compsys I, i.e., until 2007, and how its research directions were modified for Compsys II. Section  2.4 briefly presents the main achievements of Compsys II, referring to the annual reports from 2008 to 2012 for details. Finally, Section  2.5 highlights the main novelties of the past year, i.e., 2013.