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chasd00yesterday at 10:36 PM2 repliesview on HN

a compiler introducing bugs into code it compiles is a nightmare thankfully few have faced. The only thing worse would be a CPU bug like the legendary Pentium bug. Imagine you compile something like Postgres only to have it crash in some unpredictable way. How long do you stare at Postgres source before suspecting the compiler? What if this compiler was used to compile code in software running all over cloud stacks? Bugs in compilers are very bad news, they have to be correct.


Replies

ndesaulniersyesterday at 11:17 PM

Yeah, my current boss spent time weeding out such hardware bugs: https://arxiv.org/abs/2110.11519 (EDIT: maybe https://x.com/Tesla_AI/status/1930686196201714027 is a more relevant citation)

They found a bimodal distribution in failures over the lifetime of chips. Infant mortality was well understood. Silicon aging over time was much less well understood, and I still find surprising.

addaontoday at 12:46 AM

> a compiler introducing bugs into code it compiles is a nightmare thankfully few have faced

Is this true? It’s not an everyday thing, but when using less common flags, or code structures, or targets… every few years I run into a codegen issue. It’s hard to imagine going through a career without a handful…