rust/library/core
bors 4ecfdfac51 Auto merge of #100214 - scottmcm:strict-range, r=thomcc
Optimize `array::IntoIter`

`.into_iter()` on arrays was slower than it needed to be (especially compared to slice iterator) since it uses `Range<usize>`, which needs to handle degenerate ranges like `10..4`.

This PR adds an internal `IndexRange` type that's like `Range<usize>` but with a safety invariant that means it doesn't need to worry about those cases -- it only handles `start <= end` -- and thus can give LLVM more information to optimize better.

I added one simple demonstration of the improvement as a codegen test.

(`vec::IntoIter` uses pointers instead of indexes, so doesn't have this problem, but that only works because its elements are boxed.  `array::IntoIter` can't use pointers because that would keep it from being movable.)
2022-09-21 00:41:33 +00:00
..
benches
primitive_docs
src Auto merge of #100214 - scottmcm:strict-range, r=thomcc 2022-09-21 00:41:33 +00:00
tests Made from_waker, waker, from_raw const 2022-09-14 14:53:16 +02:00
Cargo.toml