RFR: 8302191: Performance degradation for float/double modulo on Linux [v5]

[Joe Darcy]

On Wed, 1 Mar 2023 12:03:54 GMT, Jan Kratochvil <duke at openjdk.org> wrote:

>> I have OCA already processed/approved. I am not Author but my Author request is being processed these days (sent to Rob McKenna).
>> I did regression test x86_64 OpenJDK-8. I will leave other regression testing on GHA.
>> The patch (and former GCC performance regression) affects only x86_64+i686.
>
> Jan Kratochvil has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix copyright author.

test/micro/org/openjdk/bench/vm/floatingpoint/DremFrem.java line 174:

> 172:             double inf_minus_inf  = Double.POSITIVE_INFINITY - Double.POSITIVE_INFINITY;
> 173:             double inf_times_zero = Double.POSITIVE_INFINITY * 0.0f;
> 174:             double quiet_nan1     = Double.longBitsToDouble(0x7ffc000000000001l);

Nit: whether or not a particular NaN bit pattern is quiet or signalling is an architecture-specific determination, it is not specified by the IEEE 754 standard.

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PR: https://git.openjdk.org/jdk/pull/12508