TL;DR
A Haskell compiler feature aimed at optimizing parallel computations unexpectedly led to the discovery of a biologist’s RNA folding algorithm. This connection could improve compiler performance and demonstrates interdisciplinary innovation. The development is ongoing, with further testing needed.
Recent discussions among Haskell compiler developers revealed that an existing optimization flag in GHC, which was disabled due to performance issues, led to an unexpected connection with an RNA folding algorithm used in biology, opening new avenues for compiler improvements and interdisciplinary research.
The issue originated from the ApplicativeDo flag (-foptimal-applicative-do) in GHC, which is disabled because the algorithm behind it is too slow—taking up to 55 seconds to compile large code blocks. The problem involves optimizing how independent computations are scheduled to reduce latency. Researchers found that the problem of scheduling these computations mirrors the RNA folding problem in biology, where the goal is to predict the most stable structure of an RNA strand based on dependencies. The compiler’s current greedy algorithm for scheduling independent statements is suboptimal, leading to performance penalties, especially with large code bases. An optimal algorithm exists with cubic complexity, but its high computational cost has limited its use. The discovery suggests that by modeling code statements as dependency trees, similar to RNA structures, it may be possible to develop more efficient algorithms. This cross-disciplinary insight could lead to faster compilation times and improved performance in Haskell programs, particularly those involving complex parallel computations.
Why It Matters
This development matters because it bridges a gap between compiler optimization techniques and biological algorithms, potentially enabling more efficient code compilation and execution. Faster compile times can improve developer productivity and application performance, especially in data-heavy or parallel processing scenarios. The finding also highlights the value of interdisciplinary approaches in solving complex computational problems, which could influence future research in both compiler design and biological modeling.

SARNA-Predict: An Algorithm for RNA Folding: Based on Free Energy MinimizationTechniques, a Permutation-based Simulated Annealing Algorithm for Ribonucleic Acid Secondary Structure Prediction
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Background
The issue traces back to the challenge of scheduling independent computations in Haskell’s GHC compiler. The default greedy algorithm often results in more rounds of network requests, increasing latency. An optimal scheduling algorithm exists but is too slow for practical use, with previous implementations taking over 50 seconds for large code blocks. The recent discovery emerged from examining the dependencies involved in this scheduling problem, revealing that the problem resembles RNA folding algorithms used in biology to predict the structure of RNA strands based on base pairing dependencies. This similarity opened the door to applying biological algorithms to compiler optimization, a novel intersection that had not been previously exploited.
“The connection between RNA folding algorithms and our scheduling problem was a surprising but promising insight. It could lead to more practical implementations of the optimal algorithm.”
— Haskell compiler developer
“RNA folding algorithms are designed to efficiently predict the most stable configurations based on dependencies, similar to what we see in scheduling independent computations.”
— Biologist specializing in RNA structures
Haskell compiler optimization tools
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What Remains Unclear
It is not yet clear how exactly the biological algorithms can be adapted for practical use in the compiler, or whether this approach will significantly outperform existing heuristics. Further research and testing are needed to validate the effectiveness of this interdisciplinary method.

Applied Parallel Computing. Industrial Computation and Optimization: Third International Workshop, PARA '96, Lyngby, Denmark, August 18-21, 1996, Proceedings (Lecture Notes in Computer Science, 1184)
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What’s Next
Next steps include developing and testing algorithms inspired by RNA folding models within the GHC compiler, benchmarking their performance against current methods, and assessing their impact on compilation speed and efficiency. Researchers also plan to explore broader applications of biological algorithms in compiler optimization and parallel computation scheduling.

An Introduction to Bioinformatics Algorithms (Computational Molecular Biology)
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Key Questions
How does the biological RNA folding algorithm relate to compiler optimization?
The RNA folding algorithm predicts the most stable structure based on dependencies, similar to scheduling independent computations in code. This analogy helps in designing more efficient algorithms for reducing compilation rounds.
Will this discovery immediately improve Haskell compiler performance?
Not immediately. The connection opens new research pathways. Practical implementation and testing are still underway to determine the real-world impact on compiler speed.
Could this interdisciplinary approach be applied to other programming languages?
Potentially, yes. The principles of dependency modeling and biological algorithms could be adapted for optimizing parallel computations in other languages and systems.
Source: Hacker News