RFR: 6506405: Math.abs(float) is slow

[Joe Darcy]

On Wed, 7 Jul 2021 20:28:37 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Please consider this change to make the `float` and `double` versions of `java.lang.Math.abs()` branch-free.

> 
> Good catch. Well that’s not good. If it needs to catch a special case it’s probably not worth doing. given the small improvement for the general case. None of the existing tests catch this corner case. On Jul 7, 2021, at 2:03 PM, Rémi Forax ***@***.******@***.***>> wrote: Your patch change the semantics, actually Math.abs(Integer.MIN_VALUE) == Integer.MIN_VALUE with your patch Math.abs(Integer.MIN_VALUE) == Integer.MAX_VALUE — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<[https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/4711*issuecomment-875931239__;Iw!!ACWV5N9M2RV99hQ!cfR3MocdWRA_0gP-3VpRbM_stXXf7VTtD7tPX9aQ07WkId8ihoEhwiCQ_wUCotsYgmlw$](https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/4711*issuecomment-875931239__;Iw!!ACWV5N9M2RV99hQ!cfR3MocdWRA_0gP-3VpRbM_stXXf7VTtD7tPX9aQ07WkId8ihoEhwiCQ_wUCotsYgmlw%24)>, or unsubscribe<[https://urldefense.com/v3/__https://github.com/notifications/unsubsc
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> 
> 
> Your patch change the semantics, actually
> `Math.abs(Integer.MIN_VALUE) == Integer.MIN_VALUE`
> with your patch
> `Math.abs(Integer.MIN_VALUE) == Integer.MAX_VALUE`

Does it? The overriding of int arguments shouldn't be affected.

-Joe

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PR: https://git.openjdk.java.net/jdk/pull/4711