[vectorIntrinsics] RFR: 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE and REVERSE_BYTES operation [v3]

[Quan Anh Mai]

On Thu, 24 Mar 2022 08:16:34 GMT, Quan Anh Mai <duke at openjdk.java.net> wrote:

>> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:
>> 
>>  - 8283413: White space removal.
>>  - 8283413: Review comments resoultion, ReverseBytes IR and x86 backend support.
>>  - Merge branch 'vectorIntrinsics' of http://github.com/openjdk/panama-vector into JDK-8283413
>>  - 8283413: Adding Ideal transform for (ReverseV (ReverseV VEC)) => VEC and (ReverseV (ReverseV VEC MASK) MASK)) => VEC
>>  - 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE operation
>
> src/hotspot/cpu/x86/x86.ad line 8982:
> 
>> 8980: 
>> 8981: // -------------------------------- Bit and Byte Reversal Vector Operations ------------------------
>> 8982: instruct vreverse_reg_avx(vec dst, vec src, vec xtmp1, vec xtmp2, vec xtmp3, rRegI rtmp) %{
> 
> This should be `legVec` as this relies on the AVX encoding

I misremembered the vector operand declaration, please ignore this.

> src/hotspot/cpu/x86/x86.ad line 9026:
> 
>> 9024: 
>> 9025: instruct vreverse_byte_reg(vec dst, vec src, rRegI rtmp) %{
>> 9026:   predicate(VM_Version::supports_avx512bw() || Matcher::vector_length_in_bytes(n) < 64);
> 
> For `!VM_Version::supports_avx512bw` this needs `legVec`

And this, too. Thanks.

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PR: https://git.openjdk.java.net/panama-vector/pull/182