Add ne, eq, fix fold bug.

[cgyurgyik]

bril2json < comparisons.bril | python3 examples/lvn.py -p -c -f | bril2txt

@main {
  a: int = const 4;
  b: int = const 3;
  c: bool = eq a b;
  print c;
}

=>

@main {
  a: int = const 4;
  b: int = const 3;
  c: bool = const false;
  print c;
}

Initially this was not folding since const == False.

[cgyurgyik]

Address #99 .

Case A

@main(a: int) {
  c: bool = eq a a;
}

=>

@main(a: int) {
  c: bool = const true; // Guaranteed
}

Case B

@main(a: int) {
  c: bool = ne a a;
}

=>

@main(a: int) {
  c: bool = const false; // Guaranteed
}

Case C

@main(a: int, b: int) {
  c: bool = eq a b;
  d: bool = ne a b;
}

=>

@main(a: int, b: int) {
  c: bool = eq a b; // Who knows???
  d: bool = ne a b; // Who knows???
}

[sampsyo]

Seems great! What do you think about adding your test cases from the issue body as test files herein?

[cgyurgyik]

Seems great! What do you think about adding your test cases from the issue body as test files herein?

Is there some place specifically LVN is tested?

[sampsyo]

Ah yeah, good point: I have them here. https://github.com/sampsyo/bril/tree/master/examples/test/lvn

[cgyurgyik]

Ah yeah, good point: I have them here. https://github.com/sampsyo/bril/tree/master/examples/test/lvn

Thanks! Didn't see those. Done.

[sampsyo]

Wahoo; perfect! Thanks!!