// Compile with -C opt-level=3 -C target-cpu=native to see autovectorization | |
#[repr(align(64))] | |
pub struct Aligned<T: ?Sized>(T); | |
// assumes input is aligned on 64-byte boundary and that | |
// input's length is a multiple of 64. | |
pub fn sum_array(input: &Aligned<[i32]>) -> i32 { | |
if input.0.len() & 63 != 0 { | |
unsafe { std::hint::unreachable_unchecked() } | |
} | |
(0..input.0.len()) | |
.map(|i| unsafe { *input.0.as_ptr().add(i) }) | |
.sum() | |
} |