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

[Brian Burkhalter]

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

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