My favorite short bit of code is from 1987:
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assembly
add.l d0,d0 subx.l d1,d1 negx.l d0 addx.l d1,d1
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You can read the paper here: https://web.stanford.edu/class/cs343/resources/superoptimizer.pdf .. basically it leans on the behavior of carry flags on the Motorola 68020. I often think about it as LLMs are really good at this sort of "superoptimizing" (though compilers are already pretty good..)
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