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This commit is contained in:
Caleb Zulawski 2023-04-25 21:37:04 -04:00
parent 394a8845c6
commit c504f01abe
1 changed files with 11 additions and 3 deletions
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14
crates/core_simd/src/vector.rs
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@ -184,12 +184,15 @@ impl<const N: usize> Swizzle<1, N> for Splat {
/// # Safety
/// Reading `ptr` must be safe, as if by `<*const [T; N]>::read_unaligned`.
const unsafe fn load(ptr: *const [T; N]) -> Self {
let mut tmp = core::mem::MaybeUninit::uninit();
// There are potentially simpler ways to write this function, but this should result in
// LLVM `load <N x T>`
let mut tmp = core::mem::MaybeUninit::<Self>::uninit();
// SAFETY: `Simd<T, N>` always contains `N` elements of type `T`. It may have padding
// which does not need to be initialized. The safety of reading `ptr` is ensured by the
// caller.
unsafe {
core::ptr::copy_nonoverlapping(ptr, tmp.as_mut_ptr() as *mut _, 1);
core::ptr::copy_nonoverlapping(ptr, tmp.as_mut_ptr().cast(), 1);
tmp.assume_init()
}
}
@ -201,9 +204,14 @@ impl<const N: usize> Swizzle<1, N> for Splat {
/// # Safety
/// Writing to `ptr` must be safe, as if by `<*mut [T; N]>::write_unaligned`.
const unsafe fn store(self, ptr: *mut [T; N]) {
// There are potentially simpler ways to write this function, but this should result in
// LLVM `store <N x T>`
// Creating a temporary helps LLVM turn the memcpy into a store.
let tmp = self;
// SAFETY: `Simd<T, N>` always contains `N` elements of type `T`. The safety of writing
// `ptr` is ensured by the caller.
unsafe { core::ptr::copy_nonoverlapping(self.as_array(), ptr, 1) }
unsafe { core::ptr::copy_nonoverlapping(tmp.as_array(), ptr, 1) }
}
/// Converts an array to a SIMD vector.