Deoptless: Speculation with Dispatched On-Stack Replacement and Specialized Continuations
summary
Deoptless claims to avoid costly deoptimizations by compiling specialized continuations at OSR points and using context dispatch to pick among them, so execution never falls back to the interpreter. Prototype implements OSR-out, OSR-in and dispatch in a JIT for R (about 300 lines of code, uses LLVM codegen), evaluates on real and synthetic suites including a stress test that injects failures 1 in 10,000, and shows up to 1–10x faster recovery from mis-speculation while keeping steady-state performance.
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