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do not inline grow_amortized #78483

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do not inline grow_amortized #78483

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3 changes: 3 additions & 0 deletions library/alloc/src/raw_vec.rs
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Expand Up @@ -389,6 +389,9 @@ impl<T, A: AllocRef> RawVec<T, A> {
// so that all of the code that depends on `T` is within it, while as much
// of the code that doesn't depend on `T` as possible is in functions that
// are non-generic over `T`.
//
// We never inline this function to keep `Vec::push` small.
#[inline(never)]
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@m-ou-se m-ou-se Oct 28, 2020 •
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In many places, #[cold] is used for this, sometimes together with #[inline(never)] on the same function. Is there some guidance somewhere on which to use where?

If these kind of functions should have #[inline(never)] instead of (or in addition to) #[cold], some of them (e.g. SyncOnceCell::initialize) should probably be updated.

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hmm, I am not really sure. It probably depends on where it is used and we would need an additional perf run 😆

I do feel like this method is kind of special as it is extremely frequently used. Not sure if SyncOnceCell is used frequently enough for this to be noticeable. Could be worth trying though

fn grow_amortized(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
// This is ensured by the calling contexts.
debug_assert!(additional > 0);
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