RFR: 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend [v2]

[Andrew Haley]

On Fri, 6 Aug 2021 09:48:50 GMT, Wang Huang <whuang at openjdk.org> wrote:

>> * In this issue, we plan to complete all missing implementation for aarch64 neon backend. For example, cast from Byte to Long, cast from Long to Byte, and so on.
>> * It may be a solver of JDK-8269866, or part of it.
>
> Wang Huang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix code style

test/hotspot/gtest/aarch64/aarch64-asmtest.py line 1541:

> 1539:                         ["fcvtzv", "__ fcvtzv(v0, __ T4S, v1);",                         "fcvtzs\tv0.4s, v1.4s"],
> 1540:                         # SVE instructions
> 1541:                         ["cpy",    "__ sve_cpy(z0, __ S, p0, v1);",                      "mov\tz0.s, p0/m, s1"],

Please use the `CPY` AArch64 instruction here, rather than `MOV`.

test/hotspot/gtest/aarch64/asmtest.out.h line 715:

> 713:     __ stxpw(r6, zr, zr, sp);                          //       stxp    w6, wzr, wzr, [sp]
> 714:     __ dup(v0, __ T16B, zr);                           //       dup     v0.16b, wzr
> 715:     __ dups(v0, __ T2S, v1);                           //       mov     s0, v1.s[0]

Please use the `DUP` AArch64 instruction here, rather than `MOV`.

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