[16] RFR(M) 8251459: Compute caller save exclusion RegMasks once

[Vladimir Kozlov]

Thanks!

Vladimir K

On 8/18/20 8:26 AM, Vladimir Ivanov wrote:
> Looks good.
> 
> Best regards,
> Vladimir Ivanov
> 
> On 18.08.2020 18:12, Vladimir Kozlov wrote:
>> https://cr.openjdk.java.net/~kvn/8251459/webrev.00/
>> https://bugs.openjdk.java.net/browse/JDK-8251459
>>
>> Claes once again found optimization for C2 code!
>>
>> Instead of per bit exclusion SOC and AS registers from debuginfo regmasks he suggested to calculate exclusion masks 
>> once in Matcher::init_spill_mask() during first compilation and use these masks to do per word exclusion.
>> We can save 27k instructions per compilation on x64 with this!
>>
>> I modified Claes's original patch by removing refactoring code to see changes more clear.
>>
>> Tested: hs-tier1-3, xcomp
>>
>> Thanks,
>> Vladimir