arXiv subjects

Iheb Nassim Aouadj

Publications and source records attributed to Iheb Nassim Aouadj.

4 recordsLinked to original sources

arXiv2025

LOOPer: A Learned Automatic Code Optimizer For Polyhedral Compilers

While polyhedral compilers have shown success in implementing advanced code transformations, they still face challenges in selecting the ones that lead to the most profitable speedups. This has motivated the use of machine learning based cost models to guide the search for polyhedral optimizations. State-of-the-art polyhedral compilers have demonstrated a viable proof-of-concept of such an approach. While promising, this approach still faces significant limitations. State-of-the-art polyhedral compilers that use a deep learning cost model only support a small subset of affine transformations, limiting their ability to explore complex code transformations. Furthermore, their applicability does not scale beyond simple programs, thus excluding many program classes from their scope, such as those with non-rectangular iteration domains or multiple loop nests. These limitations significantly impact the generality of such compilers and autoschedulers and put into question the whole approach. In this paper, we introduce LOOPer, the first polyhedral autoscheduler that uses a deep learning based cost model and covers a large space of affine transformations and programs. LOOPer allows the optimization of an extensive set of programs while being effective at applying complex sequences of polyhedral transformations. We implement and evaluate LOOPer and show that it achieves competitive speedups over the state-of-the-art. On the PolyBench benchmarks, LOOPer achieves a geometric mean speedup of 1.84x over Tiramisu and 1.42x over Pluto, two state-of-the-art polyhedral autoschedulers.

cs.PL↗

arXiv2025

A Reinforcement Learning Environment for Automatic Code Optimization in the MLIR Compiler

Code optimization is a crucial task that aims to enhance code performance. However, this process is often tedious and complex, highlighting the necessity for automatic code optimization techniques. Reinforcement Learning (RL) has emerged as a promising approach for tackling such complex optimization problems. In this project, we introduce MLIR RL, an RL environment for the MLIR compiler, dedicated to facilitating MLIR compiler research and enabling automatic code optimization. We propose a multi-discrete formulation of the action space where the action space is the Cartesian product of simpler action subspaces. We also propose a new method, called level pointers, to reduce the size of the action space related to the loop interchange transformation. This enables more efficient and effective learning of the policy. To demonstrate the effectiveness of MLIR RL, we train an RL agent to optimize MLIR Linalg code, targeting CPU. The code is generated from two domain-specific frameworks: deep-learning models generated from PyTorch, and LQCD (Lattice Quantum Chromodynamics) code generated from an LQCD compiler. The result of this work is a research environment that allows the community to experiment with novel ideas in RL-driven loop-nest optimization.

cs.LG↗

arXiv2025

Pearl: Automatic Code Optimization Using Deep Reinforcement Learning

Compilers are crucial in optimizing programs and accelerating their execution. However, optimizing programs automatically using compilers is not trivial. Recent work has attempted to use reinforcement learning (RL) to solve this problem. It has limitations though. Current methods either do not support the optimization of general loop nests or can only be used to optimize loop nests seen during training. In this paper, we propose Pearl, a novel framework that uses deep reinforcement learning to automate compiler code optimization. It uses an RL agent to select the sequence of code optimizations a compiler should apply to make the input code run faster. This agent can optimize general loop nests and can generalize to programs unseen during training. To enable the optimization of general loop nests, we propose a novel representation of the action space that allows the RL agent to select on which part of the loop nest a given code optimization should be applied. Training RL agents for loop nest optimization is slow and data-intensive. We accelerate this process by caching results and pre-training the agent. Integrated with the Tiramisu compiler, our approach streamlines optimization and outperforms existing methods. To the best of our knowledge, Pearl is the first RL-based system to support general programs composed of loop nests manipulating tensors while still being able to generalize to programs unseen during training. It is also the first to support the class of polyhedral optimizations, a class of advanced loop nest optimizations. We evaluate Pearl on a set of benchmarks, and demonstrate competitive performance improvements over state-of-the-art compilers. Notably, Pearl achieves a geometric mean speedup of 2.02x compared to Tiramisu and 3.36x compared to Pluto.

cs.PL↗

arXiv2022

Progress Report: A Deep Learning Guided Exploration of Affine Unimodular Loop Transformations

In this paper, we present a work in progress about a deep learning based approach for automatic code optimization in polyhedral compilers. The proposed technique explores combinations of affine and non-affine loop transformations to find the sequence of transformations that minimizes the execution time of a given program. This exploration is guided by a deep learning based cost model that evaluates the speedup that each sequence of transformations would yield. Preliminary results show that the proposed techniques achieve a 2.35x geometric mean speedup over state of the art polyhedral compilers (Pluto).

cs.PL↗