diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs index 5b04ae7b07e69..3b2b7ba8531ca 100644 --- a/library/core/src/ptr/mod.rs +++ b/library/core/src/ptr/mod.rs @@ -905,15 +905,15 @@ pub const unsafe fn swap_nonoverlapping(x: *mut T, y: *mut T, count: usize) { if mem::align_of::() >= mem::align_of::<$ChunkTy>() && mem::size_of::() % mem::size_of::<$ChunkTy>() == 0 { - let x: *mut MaybeUninit<$ChunkTy> = x.cast(); - let y: *mut MaybeUninit<$ChunkTy> = y.cast(); + let x: *mut $ChunkTy = x.cast(); + let y: *mut $ChunkTy = y.cast(); let count = count * (mem::size_of::() / mem::size_of::<$ChunkTy>()); // SAFETY: these are the same bytes that the caller promised were // ok, just typed as `MaybeUninit`s instead of as `T`s. // The `if` condition above ensures that we're not violating // alignment requirements, and that the division is exact so // that we don't lose any bytes off the end. - return unsafe { swap_nonoverlapping_simple(x, y, count) }; + return unsafe { swap_nonoverlapping_simple_untyped(x, y, count) }; } }; } @@ -946,7 +946,7 @@ pub const unsafe fn swap_nonoverlapping(x: *mut T, y: *mut T, count: usize) { } // SAFETY: Same preconditions as this function - unsafe { swap_nonoverlapping_simple(x, y, count) } + unsafe { swap_nonoverlapping_simple_untyped(x, y, count) } } /// Same behaviour and safety conditions as [`swap_nonoverlapping`] @@ -955,16 +955,16 @@ pub const unsafe fn swap_nonoverlapping(x: *mut T, y: *mut T, count: usize) { /// `swap_nonoverlapping` tries to use) so no need to manually SIMD it. #[inline] #[rustc_const_unstable(feature = "const_swap", issue = "83163")] -const unsafe fn swap_nonoverlapping_simple(x: *mut T, y: *mut T, count: usize) { +const unsafe fn swap_nonoverlapping_simple_untyped(x: *mut T, y: *mut T, count: usize) { + let x = x.cast::>(); + let y = y.cast::>(); let mut i = 0; while i < count { - let x: &mut T = - // SAFETY: By precondition, `i` is in-bounds because it's below `n` - unsafe { &mut *x.add(i) }; - let y: &mut T = - // SAFETY: By precondition, `i` is in-bounds because it's below `n` - // and it's distinct from `x` since the ranges are non-overlapping - unsafe { &mut *y.add(i) }; + // SAFETY: By precondition, `i` is in-bounds because it's below `n` + let x = unsafe { &mut *x.add(i) }; + // SAFETY: By precondition, `i` is in-bounds because it's below `n` + // and it's distinct from `x` since the ranges are non-overlapping + let y = unsafe { &mut *y.add(i) }; mem::swap_simple(x, y); i += 1; diff --git a/library/core/tests/ptr.rs b/library/core/tests/ptr.rs index 40b2b49bdbd7d..082d438128e20 100644 --- a/library/core/tests/ptr.rs +++ b/library/core/tests/ptr.rs @@ -783,6 +783,31 @@ fn nonnull_tagged_pointer_with_provenance() { } } +#[test] +fn swap_copy_untyped() { + // We call `{swap,copy}{,_nonoverlapping}` at `bool` type on data that is not a valid bool. + // These should all do untyped copies, so this should work fine. + let mut x = 5u8; + let mut y = 6u8; + + let ptr1 = &mut x as *mut u8 as *mut bool; + let ptr2 = &mut y as *mut u8 as *mut bool; + + unsafe { + ptr::swap(ptr1, ptr2); + ptr::swap_nonoverlapping(ptr1, ptr2, 1); + } + assert_eq!(x, 5); + assert_eq!(y, 6); + + unsafe { + ptr::copy(ptr1, ptr2, 1); + ptr::copy_nonoverlapping(ptr1, ptr2, 1); + } + assert_eq!(x, 5); + assert_eq!(y, 5); +} + #[test] fn test_const_copy() { const {