RFR: 8282431: AArch64: Add optimized rules for masked vector multiply-add/sub for SVE [v2]

[Ningsheng Jian]

On Thu, 10 Mar 2022 07:55:15 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> We have the optimized match rules for vector `"fmls,fnmla,fnmls,mla,mls"` for ARM SVE. Similarly we can also add the rules for the relative masked operations to generate the optimized predicated instructions.
>> 
>> With this patch the following masked vector multiply-add for a byte vector:
>> 
>>   mul z18.b, p7/m, z18.b, z17.b
>>   add z17.b, p0/m, z17.b, z18.b
>> 
>> could be optimized to: 
>> 
>>    mla z19.b, p0/m, z18.b, z17.b
>> 
>>  And so does the multiply-sub operations. Also the following masked fused multiply-substract for a float vector:
>> 
>>   fneg    z18.s, p7/m, z18.s
>>   fmad    z17.s, p0/m, z18.s, z16.s
>> 
>> could be optimized to: 
>> 
>>   fmsb z17.s, p0/m, z18.s, z16.s"
>> 
>>  And the same to the relative negated fused operations.
>> 
>> This patch also fixes the potential issues for the usage of `NegVF/D` in match rules. The explicit check of non-predicated vector for `NegVF/D` must be added to the match rule predicate if the `NegVF/D` is assumed to be non-masked. Otherwise, the jvm might crash if a masked` NegVF/D` with two operands is matched into a rule which assumes the `NegVF/D` in subtree has one operand.
>> 
>> Also add the jtreg tests for all the touched vector operations.
>
> Xiaohong Gong has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use the ir framework for the test

Marked as reviewed by njian (Committer).

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PR: https://git.openjdk.java.net/jdk/pull/7737