37 lines
1.2 KiB
Rust
37 lines
1.2 KiB
Rust
//! The crunchy unroller - deterministically unroll constant loops. For number "crunching".
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//!
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//! The Rust optimizer will unroll constant loops that don't use the loop variable, like this:
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//!
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//! ```ignore
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//! for _ in 0..100 {
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//! println!("Hello!");
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//! }
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//! ```
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//!
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//! However, using the loop variable will cause it to never unroll the loop. This is unfortunate because it means that you can't
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//! constant-fold the loop variable, and if you end up stomping on the registers it will have to do a load for each iteration.
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//! This crate ensures that your code is unrolled and const-folded. It only works on literals,
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//! unfortunately, but there's a work-around:
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//!
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//! ```ignore
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//! debug_assert_eq!(MY_CONSTANT, 100);
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//! unroll! {
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//! for i in 0..100 {
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//! println!("Iteration {}", i);
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//! }
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//! }
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//! ```
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//! This means that your tests will catch if you redefine the constant.
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//!
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//! To default maximum number of loops to unroll is `64`, but that can be easily increased using the cargo features:
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//!
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//! * `limit_128`
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//! * `limit_256`
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//! * `limit_512`
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//! * `limit_1024`
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//! * `limit_2048`
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#![cfg_attr(not(feature = "std"), no_std)]
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include!(concat!(env!("OUT_DIR"), "/lib.rs"));
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