The author discusses using Z3 to find inefficient integer operations in JIT traces of real benchmarks optimized by PyPy’s JIT. By translating integer operations into Z3 formulas, the author identifies redundancies and inefficiencies in the traces. Surprisingly, the author highlights the discovery of redundant operations and provides examples like int_eq(b, 1) == b and ((x & 1345) ^ 2048) – 2048 == x & 1345. By using Z3 to prove relationships between operations, the author aims to improve optimizations in JIT traces efficiently. Results so far include 94 inefficiencies identified in the JIT traces. Future steps involve manual inspection to implement optimizations.
https://pypy.org/posts/2024/07/mining-jit-traces-missing-optimizations-z3.html