Automatic Datapath Optimization using E-Graphs
Authors: Samuel Coward, George A. Constantinides, Theo Drane
AI-generated Key Points
- The paper proposes a novel approach to automate circuit design space exploration and optimize RTL datapath architectures.
- The authors utilize graph rewriting techniques, e-graphs, and equality saturation for automating RTL optimization.
- Complex transformations of one RTL into another equivalent RTL can be broken down into smaller, localized transformations.
- By representing RTL as a graph and using modern graph rewriting techniques, functionally equivalent but optimized architectures can be discovered.
- Precisely defined rewrites facilitate efficient design space exploration in designs with multiple bitwidth parameters.
- The proposed approach generates a library of optimized designs instead of a single design point typically obtained through manual optimization.
- Fuzzing techniques are used to quantify a "noise floor" in datapath logic synthesis, identifying potential errors or limitations in automated optimizations.
- Previous work on transformation-based datapath improvement is discussed, including carry-save representation and solving the multiple constant multiplication (MCM) problem.
- The authors generalize these approaches using their methodology and replicate results from prior studies.
- Overall, the proposed approach significantly reduces circuit area while considering various bitwidth parameters and has the potential to accelerate circuit design development.
Abstract: Manual optimization of Register Transfer Level (RTL) datapath is commonplace in industry but holds back development as it can be very time consuming. We utilize the fact that a complex transformation of one RTL into another equivalent RTL can be broken down into a sequence of smaller, localized transformations. By representing RTL as a graph and deploying modern graph rewriting techniques we can automate the circuit design space exploration, allowing us to discover functionally equivalent but optimized architectures. We demonstrate that modern rewriting frameworks can adequately capture a wide variety of complex optimizations performed by human designers on bit-vector manipulating code, including significant error-prone subtleties regarding the validity of transformations under complex interactions of bitwidths. The proposed automated optimization approach is able to reproduce the results of typical industrial manual optimization, resulting in a reduction in circuit area by up to 71%. Not only does our tool discover optimized RTL, but also correctly identifies that the optimal architecture to implement a given arithmetic expression can depend on the width of the operands, thus producing a library of optimized designs rather than the single design point typically generated by manual optimization. In addition, we demonstrate that prior academic work on maximally exploiting carry-save representation and on multiple constant multiplication are both generalized and extended, falling out as special cases of this paper.
Tools for this paper
Ask questions about this paper to our AI assistant
You can also chat with multiple papers at once here.
The previous summary was created more than a year ago and can be re-run (if necessary) by clicking on the Run button below.
Similar papers summarized with our AI tools
Navigate through even more similar papers through a
tree representationLook for similar papers (in beta version)
We compare the title and abstract with papers indexed in our database. For arXiv papers, we search within the same category; for DOI and other sources, we search across sources and subjects. You can rerun the search as our database grows.
Disclaimer: The AI-based summarization tool and virtual assistant provided on this website may not always provide accurate and complete summaries or responses. We encourage you to carefully review and evaluate the generated content to ensure its quality and relevance to your needs.