[11u] RFR(S): 8261022: Fix incorrect result of Math.abs() with char type

[Vladimir Kozlov]

Backport patch looks good.

Thanks,
Vladimir K

On 2/11/21 5:09 AM, Pengfei Li wrote:
> Resend
> 
>> Hi,
>>
>> I'd like to backport JDK-8261022 to jdk11u.
>>
>> Original JBS: https://bugs.openjdk.java.net/browse/JDK-8261022
>> Modified webrev: http://cr.openjdk.java.net/~pli/rfr/8261022/backport11u/
>>
>> This issue causes vectorized abs generate incorrect result when the argument
>> has char type. Root cause is that the vector abs operation is not specially
>> handled in computing vector element types after we enabled that in JDK-
>> 8222074 in jdk13. As JDK-8222074 was backported to jdk11u, jdk11u is also
>> affected.
>>
>> The patch to fix this is in jdk17 now. The fix does not apply to jdk11u cleanly,
>> as VectorNode::is_shift_opcode() is not defined in jdk11u. I have modified
>> the patch a little bit to fit this difference.
>>
>> Tested jtreg hotspot::tier1 and the newly added jtreg case. No failure after
>> the modified patch.
>>
>> --
>> Thanks,
>> Pengfei
>