Use `MaybeUninit<usize>` instead of `usize` in `Storage::swap`

`Row` contains pointer bytes, which are not valid for `usize`, therefore
`MaybeUninit<usize>` should be used instead to do an untyped copy.
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nils 2022-06-15 22:07:32 +02:00 committed by GitHub
parent d9c6c8d53e
commit ff7f74fd29
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1 changed files with 4 additions and 3 deletions

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@ -1,5 +1,6 @@
use std::cmp::{max, PartialEq};
use std::mem;
use std::mem::MaybeUninit;
use std::ops::{Index, IndexMut};
use serde::{Deserialize, Serialize};
@ -157,13 +158,13 @@ impl<T> Storage<T> {
// Cast to a qword array to opt out of copy restrictions and avoid
// drop hazards. Byte array is no good here since for whatever
// reason LLVM won't optimized it.
let a_ptr = self.inner.as_mut_ptr().add(a) as *mut usize;
let b_ptr = self.inner.as_mut_ptr().add(b) as *mut usize;
let a_ptr = self.inner.as_mut_ptr().add(a) as *mut MaybeUninit<usize>;
let b_ptr = self.inner.as_mut_ptr().add(b) as *mut MaybeUninit<usize>;
// Copy 1 qword at a time.
//
// The optimizer unrolls this loop and vectorizes it.
let mut tmp: usize;
let mut tmp: MaybeUninit<usize>;
for i in 0..4 {
tmp = *a_ptr.offset(i);
*a_ptr.offset(i) = *b_ptr.offset(i);