Tweak the vec-calloc runtime check to only apply to shortish-arrays r? `@Mark-Simulacrum` `@nbdd0121` pointed out in https://github.com/rust-lang/rust/pull/95362#issuecomment-1114085395 that LLVM currently doesn't constant-fold the `IsZero` check for long arrays, so that seems like a reasonable justification for limiting it. It appears that it's based on length, not byte size, (https://godbolt.org/z/4s48Y81dP), so that's what I used in the PR. Maybe it's a ["the number of inlining shall be three"](https://youtu.be/s4wnuiCwTGU?t=320) sort of situation. Certainly there's more that could be done here -- that generated code that checks long arrays byte-by-byte is highly suboptimal, for example -- but this is an easy, low-risk tweak. |
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| rtstartup | ||
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| stdarch@d215afe9d1 | ||
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| unwind | ||