Equality saturation

Tate, Ross; Stepp, Michael; Tatlock, Zachary; Lerner, Sorin

doi:10.1145/1480881.1480915

Cited by 91 publications

(24 citation statements)

References 34 publications

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“…Originally developed for and still used in the heart of theorem provers [De Moura and Bjùrner 2008;Detlefs et al 2005;], e-graphs have also been used to power a program optimization technique called equality saturation [Joshi et al 2002;Nandi et al 2020;Panchekha et al 2015;Premtoon et al 2020;Stepp et al 2011;Tate et al 2009;Wang et al 2020].…”

Section: E-graphsmentioning

confidence: 99%

“…Term rewriting [Dershowitz 1993] is a time-tested approach for equational reasoning in program optimization [Joshi et al 2002;Tate et al 2009], theorem proving [De Moura and Bjùrner 2008;Detlefs et al 2005], and program transformation [Andries et al 1999]. In this setting, a tool repeatedly for rw in rewrites: 7 for (subst, eclass) in egraph.ematch(rw.lhs): 8 eclass2 = egraph.add(rw.rhs.subst(subst)) 9 egraph.merge(eclass, eclass2) 10 11 return egraph.extract_best() Fig.…”

Section: Equality Saturationmentioning

confidence: 99%

“…At a high level, e-graphs Nieuwenhuis and Oliveras 2005] extend union-find [Tarjan 1975] to compactly represent equivalence classes of expressions while maintaining a key invariant: the equivalence relation is closed under congruence. 1 Over the past decade, several projects have repurposed e-graphs to implement state-of-the-art, rewrite-driven compiler optimizations and program synthesizers using a technique known as equality saturation [Joshi et al 2002;Nandi et al 2020;Panchekha et al 2015;Premtoon et al 2020;Stepp et al 2011;Tate et al 2009;Wang et al 2020]. Given an input program , equality saturation constructs an e-graph that represents a large set of programs equivalent to , and then extracts the łbestž program from .…”

Section: Introductionmentioning

confidence: 99%

“…Second, many applications critically depend on domain-specific analyses, but integrating them requires ad hoc extensions to the e-graph. The lack of a general extension mechanism has forced researchers to re-implement equality saturation from scratch several times [Panchekha et al 2015;Tate et al 2009;. These challenges limit equality saturation's practicality.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

egg: Fast and extensible equality saturation

Willsey

Nandi

Wang

et al. 2021

Proc. ACM Program. Lang.

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104

121

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An e-graph efficiently represents a congruence relation over many expressions. Although they were originally developed in the late 1970s for use in automated theorem provers, a more recent technique known as equality saturation repurposes e-graphs to implement state-of-the-art, rewrite-driven compiler optimizations and program synthesizers. However, e-graphs remain unspecialized for this newer use case. Equality saturation workloads exhibit distinct characteristics and often require ad-hoc e-graph extensions to incorporate transformations beyond purely syntactic rewrites. This work contributes two techniques that make e-graphs fast and extensible, specializing them to equality saturation. A new amortized invariant restoration technique called rebuilding takes advantage of equality saturation's distinct workload, providing asymptotic speedups over current techniques in practice. A general mechanism called e-class analyses integrates domain-specific analyses into the e-graph, reducing the need for ad hoc manipulation. We implemented these techniques in a new open-source library called egg. Our case studies on three previously published applications of equality saturation highlight how egg's performance and flexibility enable state-of-the-art results across diverse domains.

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Section: E-graphsmentioning

confidence: 99%

Section: Equality Saturationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

egg: Fast and extensible equality saturation

Willsey

Nandi

Wang

et al. 2021

Proc. ACM Program. Lang.

Self Cite

104

121

View full text Add to dashboard Cite

show abstract

“…PDG [24]), or are meant to help and combine compiler optimizations (e.g. a sea of IR nodes [17] and E-PEG [78]). However, these IRs complicate the debugging process of program compilation, and are seldom used in real-world, mainstream compilers [74].…”

Section: A More On Intermediate Represen-tationsmentioning

confidence: 99%

How to Architect a Query Compiler

Shaikhha

Klonatos

Parreaux

et al. 2016

Proceedings of the 2016 International Conference on Management of Data

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This paper studies architecting query compilers. The state of the art in query compiler construction is lagging behind that in the compilers field. We attempt to remedy this by exploring the key causes of technical challenges in need of well founded solutions, and by gathering the most relevant ideas and approaches from the PL and compilers communities for easy digestion by database researchers. All query compilers known to us are more or less monolithic template expanders that do the bulk of the compilation task in one large leap. Such systems are hard to build and maintain. We propose to use a stack of multiple DSLs on different levels of abstraction with lowering in multiple steps to make query compilers easier to build and extend, ultimately allowing us to create more convincing and sustainable compiler-based data management systems. We attempt to derive our advice for creating such DSL stacks from widely acceptable principles. We have also re-created a well-known query compiler following these ideas and report on this effort.

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