crunchy (0.2.4)

Published 2026-03-26 10:56:49 +00:00 by siennathesane

Set up this registry in the Cargo configuration file (for example ~/.cargo/config.toml):

[registry]
default = "gitea"

[registries.gitea]
index = "sparse+" # Sparse index
# index = "" # Git

[net]
git-fetch-with-cli = true

To install the package using Cargo, run the following command:

cargo add crunchy@0.2.4

For more information on the Cargo registry, see the documentation.

Crunchy unroller: deterministically unroll constant loops

Crunchy

The crunchy unroller - deterministically unroll constant loops. For number "crunching".

The Rust optimizer will unroll constant loops that don't use the loop variable, like this:

for _ in 0..100 {
  println!("Hello!");
}

However, using the loop variable will cause it to never unroll the loop. This is unfortunate because it means that you can't constant-fold the loop variable, and if you end up stomping on the registers it will have to do a load for each iteration. This crate ensures that your code is unrolled and const-folded. It only works on literals, unfortunately, but there's a work-around:

debug_assert_eq!(MY_CONSTANT, 100);
unroll! {
  for i in 0..100 {
    println!("Iteration {}", i);
  }
}

This means that your tests will catch if you redefine the constant.

To default maximum number of loops to unroll is 128, but that can be easily decreased or increased using the cargo features:

limit_64
limit_128
limit_256
limit_512
limit_1024
limit_2048

Details

Cargo

2026-03-26 10:56:49 +00:00

0

Eira Fransham <jackefransham@gmail.com>

Project Site

Repository Site

MIT

3.7 KiB

Assets (1)

crunchy-0.2.4.crate 3.7 KiB

Versions (1) View all

0.2.4

2026-03-26

crunchy (0.2.4)

Installation

About this package

Crunchy