RFR: 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend [v4]

[Wu Yan]

On Fri, 3 Sep 2021 03:21:10 GMT, Ningsheng Jian <njian at openjdk.org> wrote:

>> Wang Huang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix codes
>
> src/hotspot/cpu/aarch64/aarch64_neon.ad line 187:
> 
>> 185:   format %{ " # reinterpret $dst,$src\t# S2X" %}
>> 186:   ins_encode %{
>> 187:     // The upper bits of "src" are expected to have been initialized to zero.
> 
> I think the comment should be:
> 
> // The higher bits of the "dst" register must be cleared to zero.

Thanks, I'll fix it.

> src/hotspot/cpu/aarch64/assembler_aarch64.hpp line 2910:
> 
>> 2908:   INSN(frintm, 0, 0b00, 0b01, 0b11001);
>> 2909:   INSN(frintp, 0, 0b10, 0b01, 0b11000);
>> 2910:   INSN(fcvtzv, 0, 0b10, 0b01, 0b11011); // converts each element in a vector from a floating-point value to a signed integer value, and Arm's name is fcvtzs
> 
> Would using "fcvtzs" name directly looks easier to understand (align with the manual)?

"fcvtzs" has been used here: 
https://github.com/openjdk/jdk/blob/c640fe42c2b5e6668a2a875678be44443942c868/src/hotspot/cpu/aarch64/assembler_aarch64.hpp#L2030

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PR: https://git.openjdk.java.net/jdk/pull/4839