Add abs and make Oliver's example work

[ajpal]

// ARGS: 20
fn unrelated_fn(input: i64, res: i64) -> i64 {
    return input / (res / 3);
}

fn other_unrelated_fn(input: i64, res: i64) -> i64 {
    return res / (input / 5);
}

fn main(input: i64) {
    let mut res: i64 = abs(input) * 2;

    if (input > 0) {
        res = res + abs(input) - input;
        res = unrelated_fn(input, res);
    } else {
        res = res + abs(input) + input;
        res = other_unrelated_fn(input, res);
    }

    println!("{}", res);
}

Output bril:

# ARGS: 20
@unrelated_fn(v0: int, v1: int): int {
.b2_:
  c3_: int = const 3;
  v4_: int = div v1 c3_;
  v5_: int = div v0 v4_;
  ret v5_;
}
@other_unrelated_fn(v0: int, v1: int): int {
.b2_:
  c3_: int = const 5;
  v4_: int = div v0 c3_;
  v5_: int = div v1 v4_;
  ret v5_;
}
@main(v0: int) {
.b1_:
  c2_: int = const 0;
  v3_: bool = gt v0 c2_;
  v4_: int = abs v0;
  c5_: int = const 2;
  v6_: int = mul c5_ v4_;
  br v3_ .b7_ .b8_;
.b7_:
  c9_: int = const 3;
  v10_: int = div v6_ c9_;
  v11_: int = div v0 v10_;
  v12_: int = id v11_;
  print v12_;
  ret;
  jmp .b13_;
.b8_:
  c14_: int = const 5;
  v15_: int = div v0 c14_;
  v16_: int = div v6_ v15_;
  v12_: int = id v16_;
  print v12_;
  ret;
.b13_:
}

SVGs
Before

After

[oflatt]

Good but one of your rules seems unsound

[oflatt]

it's not true 😭

[oflatt]

Looks good, you just have to fix CI
Look over the snapshots for our example carefully!