[vectorIntrinsics] RFR: 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE operation [v2]

[Jatin Bhateja]

On Tue, 22 Mar 2022 17:22:50 GMT, Quan Anh Mai <duke at openjdk.java.net> wrote:

>> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 4498:
>> 
>>> 4496: #endif
>>> 4497: 
>>> 4498: void C2_MacroAssembler::vector_reverse_byte_avx(BasicType bt, XMMRegister dst, XMMRegister src,
>> 
>> Since this is an in-lane shuffle, can we just use `vpshufb` for this?
>> Thanks.
>
> We are doing an element-wise byte reverse not a whole vector byte reverse I think we don't need any cross-lane shuffle here.
> Thanks.

Removed incorrect comments. your comments seems valid here.

-------------

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