Use drop_in_place in Vec and VecDeque
#32012
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Directly use the drop glue for [T]. Still optimizes out in -O1 like with the `needs_drop` intrinsic.
Just like for Vec. This should benefit both non-optimized and optimized performance. Non-optimized since the intrinsic drop_in_place is easily removed, and optimized because iterating the slices is more efficient than using the VecDeque iterators.
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r? @gankro (rust_highfive has picked a reviewer for you, use r? to override) |
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| } | ||
| // use drop for [T] | ||
| ptr::drop_in_place(&mut self[..]); |
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Whoa I had no idea this was possible, nifty!
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Use `drop_in_place` in Vec and VecDeque We can use drop_in_place's DST capabilities directly in Vec::drop and similarly in VecDeque::drop. I verfied this has the same effect as the previous `needs_drop` code; `drop_in_place` it itself an intrinsic. The VecDeque replacement should be more efficient too, even in release mode (slice iteration makes a more efficient loop than the deque iterator).
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This is what the standard Vec does; see rust-lang/rust#32012.
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Use a single ptr::drop_in_place call instead of a loop This is what the standard Vec does; see rust-lang/rust#32012. <!-- Reviewable:start --> --- This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/rust-smallvec/100) <!-- Reviewable:end -->
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Use
drop_in_placein Vec and VecDequeWe can use drop_in_place's DST capabilities directly in Vec::drop and similarly in VecDeque::drop. I verfied this has the same effect as the previous
needs_dropcode;drop_in_placeit itself an intrinsic.The VecDeque replacement should be more efficient too, even in release mode (slice iteration makes a more efficient loop than the deque iterator).