Acknowledged
8 months ago

Bug in Simulator 7.2.1 with Float vs Long comparisons

In the following:

    var l = 1L;
    var f = 1.0f;
    System.println(f==l); // false in 7.2.1, true in 7.2.0 and earlier
    System.println(l==f); // false in 7.2.1, true in 7.2.0 and earlier
    System.println(1.0f==1L); // false in 7.2.1 with optimization off, true with optimization on

Essentially, when the 7.2.1 simulator evaluates 1.0f==1L it returns false. All previous simulators return true.

Note that the optimizer also thinks the result is true.

I've not tried on a device yet, but from past experiments I'm pretty sure that all the watches I've used report true.

If this is something that's going to change, or that devices are inconsistent about, the type checker should issue a warning for long vs float comparisons, and the optimizer shouldn't optimize constant comparisons (especially not to the wrong value!). But my guess is that this is just a bug in the simulator.

markw65
Parents
  • 8 months ago in reply to FlowState

    For MonkeyC, it appears that Number vs Float, Long, Double or Char returns true when you would expect it to, as do most of the other pairwise comparisons. Amongst those types, there are just the 4 I listed that don't, and that's only for "older" devices. With "newer" devices all the pairwise comparisons return true.

    This is unfortunate, because it seems like the ones that don't behave have always not behaved; but the simulator got it wrong. Even now the optimizer gets it wrong, which makes things even more confusing.

Comment
  • 8 months ago in reply to FlowState

    For MonkeyC, it appears that Number vs Float, Long, Double or Char returns true when you would expect it to, as do most of the other pairwise comparisons. Amongst those types, there are just the 4 I listed that don't, and that's only for "older" devices. With "newer" devices all the pairwise comparisons return true.

    This is unfortunate, because it seems like the ones that don't behave have always not behaved; but the simulator got it wrong. Even now the optimizer gets it wrong, which makes things even more confusing.

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