Review request for JDK-8141407: Wrong evaluation of a != a when a = NaN

Hannes Wallnoefer hannes.wallnoefer at
Mon Nov 23 15:53:52 UTC 2015

Am 2015-11-23 um 16:05 schrieb Attila Szegedi:
> +1. As you correctly point out, this was caused by JDK-8043608. Strangely enough, I fixed the NaN case for strictEquals() with JDK-8044786, but I remember reasoning that it wasn’t an issue for equals(). Apparently, that was wrong…

The reason may be that the bug manifests itself only if the value is 
actually stored as an object. If it is stored as primitive it will be 
wrapped as two different java.lang.Double instances s for both sides of 
the comparison, making it behave as expected.

Now even with optimistic types disabled, we have code that narrows the 
type of new properties so it will be of double type. (I wonder if it's a 
good idea to do that without optimstic types / dual fields?)

I've updated the webrev in-place to make that mechanism more explicit in 
the test comments and code by mixing in some object assignments.


> Attila.
>> On Nov 23, 2015, at 3:35 PM, Hannes Wallnöfer <hannesw at> wrote:
>> Please review JDK-8141407: Wrong evaluation of a != a when a = NaN:
>> Thanks,
>> Hannes

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