RFR: JDK-8302736: Major performance regression in Math.log on aarch64

[Joseph D. Darcy]

There hasn't been any performance tuning of the FDLIBM methods so I 
wouldn't propose retiring the intrinsics. (And the intrinsics might also 
be more accurate than the FDLIBM algorithms.)

I wanted to send the prior comment to point out that Math vs StrictMath 
performance ratios would be different on JDK 21 vs 20 and earlier releases.

-Joe

On 5/14/2023 3:33 AM, Andrew Haley wrote:
> On Fri, 12 May 2023 23:23:41 GMT, Joe Darcy <darcy at openjdk.org> wrote:
>
>> As a general comment, in case it is relevant, the remaining FDLIBM algorithms that were not already ported to Java have been ported to Java earlier in JDK 21 (JDK-8171407). This may change the performance of StrictMath.${FOO} methods on a given platform compared to earlier JDK releases.
> Good point. I'd forgotten about that. Maybe we should simply disable the intrinsic.
>
> -------------
>
> PR Comment: https://git.openjdk.org/jdk/pull/13606#issuecomment-1546865866