RFR: 8287139: aarch64 intrinsic for unsignedMultiplyHigh

[Raffaello Giulietti]

On Mon, 23 May 2022 12:50:28 GMT, Ningsheng Jian <njian at openjdk.org> wrote:

>> Adds aarch64 intrinsic support for `Math.unsignedMultiplyHigh()`
>
> src/hotspot/cpu/aarch64/aarch64.ad line 11146:
> 
>> 11144: %}
>> 11145: 
>> 11146: instruct umulHiL_rReg(iRegLNoSp dst, iRegL src1, iRegL src2, rFlagsReg cr)
> 
> `rFlagsReg cr` is not used.

Yes, I noticed, but since there are many more unused `rFlagsReg cr` in the file and since I don't know its semantics, I prefer to just leave it as it is.

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PR: https://git.openjdk.java.net/jdk/pull/8840