[vectorIntrinsics] RFR: 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE and REVERSE_BYTES operation [v6]

[Jatin Bhateja]

On Wed, 20 Jul 2022 07:00:18 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> Yeah, I know that is used to skip the transformations. I'm just curious why we need to skip the optimizations if it is used by a `VectorBlend`. Did you met any issues or something others? Thanks! I want to add a transformation such as `(ReverseBytesV src) => src` if the basic element type is T_BYTE. I cannot see the reason that I need to also skip this transformation for VectorBlend used ReverseBytesV. Maybe we can continue the discussion after I created a PR for it. WDYT?
>
> Please refer to the PR https://github.com/openjdk/jdk/pull/9565. Thanks a lot!

> Yeah, I know that is used to skip the transformations. I'm just curious why we need to skip the optimizations if it is used by a `VectorBlend`. Did you met any issues or something others? Thanks! I want to add a transformation such as `(ReverseBytesV src) => src` if the basic element type is T_BYTE. I cannot see the reason that I need to also skip this transformation for VectorBlend used ReverseBytesV. Maybe we can continue the discussion after I created a PR for it. WDYT?

It was purely to skip matching over bigger graph pallet at that point, with blends pattern matching will be slightly complex and will need to be handled in VectorBlend idealization routines.

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