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A DSL for peephole transformation rules of integer operations in the PyPy JIT

As is probably apparent from the sequence of blog posts about the topic in the last year, I have been thinking about and working on integer optimizations in the JIT compiler a lot. This work was mainl

In this post I'll describe my most recent change, which is a new small domain specific language that I implemented to specify peephole optimizations on integer operations in the JIT. To make it less likely to introduce incorrect optimizations into the JIT, the rules are automatically proven correct with Z3 as part of the build process (for a more hands-on intro to how that works you can look at the post). The JIT has like half of an e-graph data structure already, and we probably can't afford a full one in terms of compile time costs, but maybe we can have two thirds or something?

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