main.ll

; [...]

  %1 = load i8, i8* %value
  switch i8 %1, label %bb21 [
    i8 0, label %bb1
    i8 1, label %bb2
    i8 2, label %bb3
    i8 3, label %bb4
    i8 4, label %bb5
    i8 5, label %bb6
    i8 6, label %bb7
    i8 7, label %bb8
    i8 8, label %bb9
    i8 9, label %bb10
    i8 10, label %bb11
    i8 11, label %bb12
    i8 12, label %bb13
    i8 13, label %bb14
    i8 14, label %bb15
    i8 15, label %bb16
    i8 16, label %bb17
    i8 17, label %bb18
    i8 18, label %bb19
    i8 19, label %bb20
  ]


; [...]

main.rs

use std::io;
use std::io::BufRead;

pub fn match_(value: u8) {
    match value {
        0x0 => println!("0x0"),
        0x1 => println!("0x1"),
        0x2 => println!("0x2"),
        0x3 => println!("0x3"),
        0x4 => println!("0x4"),
        0x5 => println!("0x5"),
        0x6 => println!("0x6"),
        0x7 => println!("0x7"),
        0x8 => println!("0x8"),
        0x9 => println!("0x9"),
        0xA => println!("0xA"),
        0xB => println!("0xB"),
        0xC => println!("0xC"),
        0xD => println!("0xD"),
        0xE => println!("0xE"),
        0xF => println!("0xF"),
        0x10 => println!("0x10"),
        0x11 => println!("0x11"),
        0x12 => println!("0x12"),
        0x13 => println!("0x13"),

        _ => { }
    }
}

fn main() {
    let mut line = String::new();
    let stdin = io::stdin();
    stdin.lock().read_line(&mut line).unwrap();

    let len = line.len();
    line.truncate(len - 1);

    let value: u8 = line.parse().unwrap();

    match_(value);
}