vers_vecs/util/
unroll.rs

1//! Unroll a loop a fixed number of times. This is a macro that performs manual loop unrolling,
2//! because LLVM is sometimes too conservative to do it itself.
3//! We only use it in hyper-optimized code paths like ``rank``.
4
5macro_rules! unroll {
6    (1, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { let mut $i: usize = $e; $s };
7    (2, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(1, |$i = {$e}| $s, $inc); $inc; $s };
8    (3, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(2, |$i = {$e}| $s, $inc); $inc; $s };
9    (4, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(3, |$i = {$e}| $s, $inc); $inc; $s };
10    (5, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(4, |$i = {$e}| $s, $inc); $inc; $s };
11    (6, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(5, |$i = {$e}| $s, $inc); $inc; $s };
12    (7, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(6, |$i = {$e}| $s, $inc); $inc; $s };
13    (8, |$i:ident = {$e:expr}| $s:stmt, $inc:expr) => { unroll!(7, |$i = {$e}| $s, $inc); $inc; $s };
14}
15
16// export the macro to the crate
17pub(crate) use unroll;
vers_vecs/util/unroll.rs

vers_vecs/util/
unroll.rs
