RFR: 8268229: Aarch64: Use Neon in intrinsics for String.equals [v3]
Andrew Haley
aph at openjdk.java.net
Mon Jul 5 09:23:49 UTC 2021
On Mon, 5 Jul 2021 08:19:51 GMT, Nick Gasson <ngasson at openjdk.org> wrote:
>> * Why we unroll the loop ?
>> * It is found that these codes degrades performance
>> ```
>> br(LE, B16);
>> subs(cnt1, cnt1, wordSize);
>> br(LE, B24);
>> subs(cnt1, cnt1, wordSize);
>>
>> We unroll the loop to remove these comparsion.
>
> But we need to balance performance against code size, given that this is expanded frequently.
Nick is right. This unrolling at the call site is not going to be accepted.
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PR: https://git.openjdk.java.net/jdk/pull/4423
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