Maybe OP was thinking about compilers "cracking" certain SPEC benchmarks: implementing exactly the optimization needed to boost a benchmark quite a lot, but that opt. probably won't apply to any other code out there (usually it's so targeted and risky with general C/C++ code that intentionally it doesn't work on anything else). That happened a couple of times over the years, I know about the Intel compiler cases for ex. I can certainly see LLM providers adding tricks that help a certain class of benchmarks, but doesn't help much for anything else.