Andreas Kling on X: "Had a strange performance regression from a seemingly innocuous code change, and GPT-5.6 tracked it down to a microcode workaround for an Intel CPU bug.
The workaround can make conditional jumps that straddle a 32-byte boundary much slower, so programs have to be laid out around" / X<br>Post
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Andreas Kling
@awesomekling
Had a strange performance regression from a seemingly innocuous code change, and GPT-5.6 tracked it down to a microcode workaround for an Intel CPU bug.
The workaround can make conditional jumps that straddle a 32-byte boundary much slower, so programs have to be laid out around it.
Tried building with -mbranches-within-32B-boundaries and wouldn't you know it, we're fast again!
The future is so fucking cool!
intel.com/content/www/us…<br>Mitigation Strategies for JCC Microcode
From intel.com
span:not(:empty)~span:not(:empty)]:before:content-['·'] [&>span:not(:empty)~span:not(:empty)]:before:px-1 [&>span:not(:empty)~span:not(:empty)]:before:shrink-0">12:56 PM · Jul 22, 2026180Views
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