RFR: 8320448: Accelerate IndexOf using AVX2 [v19]

Sat May 18 00:02:17 UTC 2024

On Tue, 14 May 2024 00:38:30 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> Scott Gibbons has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rearrange; add lambdas for clarity
>
> src/hotspot/cpu/x86/stubGenerator_x86_64_string.cpp line 1178:
> 
>> 1176:     __ andq(eq_mask, lastMask);
>> 1177:     if (needToSaveRCX) {
>> 1178:       __ movdq(rcx, saveRCX);
> 
> movdq is an expensive instruction (about 3 cycle). If we have another gpr temporary available here for shiftVal, then we dont need to do save/restore rcx.

No longer need to use rcx.  Refactored.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/16753#discussion_r1605619614