Jordi Armengol-Estapé

dblp:263/2700 · DBLP profile ↗
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7ranked-venue papers
3as first author
7since 2021 · last 2025
0000-0001-8893-6185ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 3 · 2 first-author · 3 since 2021Software engineering, systems software and programming languages · 3 · 1 first-author · 3 since 2021Systems, architecture and hardware · 2 · 1 first-author · 2 since 2021
YearPublicationVenuePosition
2025 Guess, Measure & Edit: Using Lowering to Lift Tensor Code
abstract
Recently, we have observed a steady growth in specialized hardware accelerators. These accelerators are typically programmed in high-level domain-specific languages (DSLs), enabling compilers to generate efficient code for rapidly evolving heterogeneous hardware. However, rewriting existing code to exploit DSL compiler performance is an onerous programmer task. This has led to recent interest in automatically translating or lifting code to DSLs. Current lifting techniques use language models or program synthesis to translate code. Although language models have proved remarkably successful in related translation tasks, they are prone to hallucinations. Program synthesis approaches are accurate but do not scale to complex tensor DSLs. This paper presents a novel approach, Guess, Measure & Edit; that exploits both language models and compiler technology to lift existing code to high-level DSLs. Given a source program, it uses a language model to guess an initial equivalent target program. It then compiles or lowers the guess and the original program, and measures the low-level distance between them using program similarity metrics. It iteratively uses these low-level metrics to guide high-level edits to the guess until it is correct. To validate this approach, we develop KONRUL which correctly lifts existing tensor algebra C code to einsum notation, the basis of tensor contraction DSLs. Our evaluation shows that KONRUL is fast and accurate, lifting 98% of an extensive benchmark suite and significantly outperforming 4 state-of-theart lifting schemes. KONRUL is scalable and is the only approach to correctly lift higher-dimensional tensor contraction code. Our lifted programs result in geomean speedups of $4.07 \times$ and $38.30 \times$ when ported to a multi-core CPU and GPU respectively.
José Wesley de S. Magalhães, Jackson Woodruff, Jordi Armengol-Estapé, Alexander Brauckmann, Luc Jaulmes, Elizabeth Polgreen, Michael F. P. O'Boyle
PACT3
2024 SLaDe: A Portable Small Language Model Decompiler for Optimized Assembly
abstract
Decompilation is a well-studied area with numerous high-quality tools available. These are frequently used for security tasks and to port legacy code. However, they regularly generate difficult-to-read programs and require a large amount of engineering effort to support new programming languages and ISAs. Recent interest in neural approaches has produced portable tools that generate readable code. Nevertheless, to-date such techniques are usually restricted to synthetic programs without optimization, and no models have evaluated their portability. Furthermore, while the code generated may be more readable, it is usually incorrect. This paper presents SLaDe, a Small Language model Decompiler based on a sequence-to-sequence Transformer trained over real-world code and augmented with a type inference engine. We utilize a novel tokenizer, dropout-free regularization, and type inference to generate programs that are more readable and accurate than standard analytic and recent neural approaches. Unlike standard approaches, SLaDe can infer out-of-context types and unlike neural approaches, it generates correct code. We evaluate SLaDe on over 4,000 ExeBench functions on two ISAs and at two optimization levels. SLaDe is up to 6× more accurate than Ghidra, a state-of-the-art, industrial-strength decompiler and up to 4× more accurate than the large language model ChatGPT and generates significantly more readable code than both.
Jordi Armengol-Estapé, Jackson Woodruff, Chris Cummins, Michael F. P. O'Boyle
CGO1
2023 Matching Linear Algebra and Tensor Code to Specialized Hardware Accelerators
abstract
Dedicated tensor accelerators demonstrate the importance of linear algebra in modern applications. Such accelerators have the potential for impressive performance gains, but require programmers to rewrite code using vendor APIs - a barrier to wider scale adoption. Recent work overcomes this by matching and replacing patterns within code, but such approaches are fragile and fail to cope with the diversity of real-world codes.
Pablo Antonio Martínez, Jackson Woodruff, Jordi Armengol-Estapé, Gregorio Bernabé, José M. García 0001, Michael F. P. O'Boyle
CC3
2022 On the Multilingual Capabilities of Very Large-Scale English Language Models
abstract
Generative Pre-trained Transformers (GPTs) have recently been scaled to unprecedented sizes in the history of machine learning. These models, solely trained on the language modeling objective, have been shown to exhibit outstanding zero, one, and few-shot learning capabilities in a number of different tasks. Nevertheless, aside from anecdotal experiences, little is known regarding their multilingual capabilities, given the fact that the pre-training corpus is almost entirely composed of English text. In this work, we investigate its potential and limits in three tasks: extractive question-answering, text summarization and natural language generation for five different languages, as well as the effect of scale in terms of model size. Our results show that GPT-3 can be almost as useful for many languages as it is for English, with room for improvement if optimization of the tokenization is addressed.
Jordi Armengol-Estapé, Ona de Gibert Bonet, Maite Melero
LREC1
2022 Unsupervised Machine Translation in Real-World Scenarios
abstract
In this work, we present the work that has been carried on in the MT4All CEF project and the resources that it has generated by leveraging recent research carried out in the field of unsupervised learning. In the course of the project 18 monolingual corpora for specific domains and languages have been collected, and 12 bilingual dictionaries and translation models have been generated. As part of the research, the unsupervised MT methodology based only on monolingual corpora (Artetxe et al., 2017) has been tested on a variety of languages and domains. Results show that in specialised domains, when there is enough monolingual in-domain data, unsupervised results are comparable to those of general domain supervised translation, and that, at any rate, unsupervised techniques can be used to boost results whenever very little data is available.
Ona de Gibert Bonet, Iakes Goenaga, Jordi Armengol-Estapé, Olatz Perez-de-Viñaspre, Carla Parra Escartín, Marina Sanchez, Marcis Pinnis, Gorka Labaka, Maite Melero
LREC3
2022 Bind the gap: compiling real software to hardware FFT accelerators
abstract
Specialized hardware accelerators continue to be a source of performance improvement. However, such specialization comes at a programming price. The fundamental issue is that of a mismatch between the diversity of user code and the functionality of fixed hardware, limiting its wider uptake. Here we focus on a particular set of accelerators: those for Fast Fourier Transforms. We present FACC (Fourier ACcelerator Compiler), a novel approach to automatically map legacy code to Fourier Transform accelerators. It automatically generates drop-in replacement adapters using Input-Output (IO)-based program synthesis that bridge the gap between user code and accelerators. We apply FACC to unmodified GitHub C programs of varying complexity and compare against two existing approaches. We target FACC to a high-performance library, FFTW, and two hardware accelerators, the NXP PowerQuad and the Analog Devices FFTA, and demonstrate mean speedups of 9x, 17x and 27x respectively
Jackson Woodruff, Jordi Armengol-Estapé, Sam Ainsworth 0001, Michael F. P. O'Boyle
PLDI2
2021 Semantic and syntactic information for neural machine translation
abstract
Abstract Introducing factors such as linguistic features has long been proposed in machine translation to improve the quality of translations. More recently, factored machine translation has proven to still be useful in the case of sequence-to-sequence systems. In this work, we investigate whether this gains hold in the case of the state-of-the-art architecture in neural machine translation, the Transformer, instead of recurrent architectures. We propose a new model, the Factored Transformer, to introduce an arbitrary number of word features in the source sequence in an attentional system. Specifically, we suggest two variants depending on the level at which the features are injected. Moreover, we suggest two combination mechanisms for the word features and words themselves. We experiment both with classical linguistic features and semantic features extracted from a linked data database, and with two low-resource datasets. With the best-found configuration, we show improvements of 0.8 BLEU over the baseline Transformer in the IWSLT German-to-English task. Moreover, we experiment with the more challenging FLoRes English-to-Nepali benchmark, which includes both low-resource and very distant languages, and obtain an improvement of 1.2 BLEU. These improvements are achieved with linguistic and not with semantic information.
Jordi Armengol-Estapé, Marta R. Costa-jussà
Mach. Transl.1