Theory and Practice of Fusion

Hinze, Ralf; Harper, Thomas L.; James, Daniel

doi:10.1007/978-3-642-24276-2_2

Cited by 16 publications

(9 citation statements)

References 17 publications

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“…Some approaches use category theory to reason about deforestation and fusion [7]. Takano and Meijer [21] extended shortcut deforestation beyond lists, to other data structures.…”

Section: Deforestation and Stream Fusionmentioning

confidence: 99%

Postcondition-preserving fusion of postorder tree transformations

Davies

Kalvala

2020

Proceedings of the 29th International Conference on Compiler Construction

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Tree transformations are common in applications such as program rewriting in compilers. Using a series of simple transformations to build a more complex system can make the resulting software easier to understand, maintain, and reason about. Fusion strategies for combining such successive tree transformations promote this modularity, whilst mitigating the performance impact from increased numbers of tree traversals. However, it is important to ensure that fused transformations still perform their intended tasks. Existing approaches to fusing tree transformations tend to take an informal approach to soundness, or be too restrictive to consider the kind of transformations needed in a compiler. We use postconditions to define a more useful formal notion of successful fusion, namely postcondition-preserving fusion. We also present criteria that are sufficient to ensure postcondition-preservation and facilitate modular reasoning about the success of fusion. CCS Concepts • Software and its engineering → Compilers; • Theory of computation → Program reasoning.

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“…Some approaches use category theory to reason about deforestation and fusion [7]. Takano and Meijer [21] extended shortcut deforestation beyond lists, to other data structures.…”

Section: Deforestation and Stream Fusionmentioning

confidence: 99%

Postcondition-preserving fusion of postorder tree transformations

Davies

Kalvala

2020

Proceedings of the 29th International Conference on Compiler Construction

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“…D'Antoni et al [2014] specifically look at deforestation in programs that manipulate trees. While deforestation originally adopted a syntactic, rewrite-based approach, later work focused on providing deforestation benefits by translating programs that traverse data structures to use combinators with known fusion rules (Hinze et al [2011] provide a survey). For example, fusion rules for monadic folds [Meijer and Jeuring 1995] handle fusing operations that maintain state.…”

Section: Related Workmentioning

confidence: 99%

TreeFuser: a framework for analyzing and fusing general recursive tree traversals

Sakka

Sundararajah

Kulkarni

2017

Proc. ACM Program. Lang.

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Series of traversals of tree structures arise in numerous contexts: abstract syntax tree traversals in compiler passes, rendering traversals of the DOM in web browsers, kd-tree traversals in computational simulation codes. In each of these settings, a tree is traversed multiple times to compute various values and modify various portions of the tree. While it is relatively easy to write these traversals as separate small updates to the tree, for efficiency reasons, traversals are often manually fused to reduce the number of times that each portion of the tree is traversed: by performing multiple operations on the tree simultaneously, each node of the tree can be visited fewer times, increasing opportunities for optimization and decreasing cache pressure and other overheads. This fusion process is often done manually, requiring careful understanding of how each of the traversals of on tree interact. This paper presents an automatic approach to traversal fusion: tree traversals can be written independently, and then our framework analyzes the dependences between the traversals to determine how they can be fused to reduce the number of visits to each node in the tree. A critical aspect of our framework is that it exploits two opportunities to increase the amount of fusion: i) it automatically integrates code motion, and ii) it supports partial fusion, where portions of one traversal can be fused with another, allowing for a reduction in node visits without requiring that two traversals be fully fused. We implement our framework as Clang tool, and show across several case studies that we can successfully fuse complex tree traversals, reducing the overall number of traversals and substantially improving locality and performance. CCS Concepts: • Software and its engineering → Automated static analysis; Compilers;

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“…The CPS-encoded datatypes (FoldLeft, EitherCPS) used in this paper are instances of such algebras. Hinze et al provide a theoretical framework that unifies the above-mentioned fusion algorithms [6]. Ghani et al generalise foldr/build fusion to other inductive datatypes [4].…”

Section: Related Workmentioning

confidence: 99%

“…Its goal is to avoid the creation of costly intermediate data structures. Fusion has been extensively studied, both theoretically [6] and in practice [2,5,14].…”

Section: Introductionmentioning

confidence: 99%

Fold-based fusion as a library: a generative programming pearl

Jonnalagedda

Stucki

2015

Proceedings of the 6th ACM SIGPLAN Symposium on Scala

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Fusion is a program optimisation technique commonly implemented using special-purpose compiler support. In this paper, we present an alternative approach, implementing fold-based fusion as a standalone library. We use staging to compose operations on folds; the operations are partially evaluated away, yielding code that does not construct unnecessary intermediate data structures. The technique extends to partitioning and grouping of collections.

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Theory and Practice of Fusion

Cited by 16 publications

References 17 publications

Postcondition-preserving fusion of postorder tree transformations

Postcondition-preserving fusion of postorder tree transformations

TreeFuser: a framework for analyzing and fusing general recursive tree traversals

Fold-based fusion as a library: a generative programming pearl

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