Efficient E-Matching: A New Weapon for Optimizing Compilers
2025-04-20
Modern theorem provers and optimizing compilers rely on a clever technique: E-matching. It matches not only syntax but, more importantly, semantics, achieving equivalence reasoning through E-graphs and congruence closure. This article delves into the principles of E-matching, particularly how to efficiently find matching patterns in E-graphs using discrimination trees and congruence closure, avoiding the inefficiency of traditional recursive traversal. The author also introduces its application in the Zob compiler, compiling patterns into virtual machine instructions for efficient pattern matching, significantly improving optimization efficiency.