RFR: 8301739: AArch64: Add optimized rules for vector compare with immediate for SVE [v3]

[Chang Peng]

> We can use SVE compare-with-integer-immediate instructions like cmpgt(immediate)[1] to avoid the extra scalar2vector operations.
> 
> The following instruction sequence
> 
> 
> movi    v17.16b, #12
> cmpgt   p0.b, p7/z, z16.b, z17.b
> 
> 
> can be optimized to:
> 
> 
> cmpgt   p0.b, p7/z, z16.b, #12
> 
> 
> This patch does the following:
> 1. Add SVE compare-with-7bit-unsigned-immediate instructions to C2's backend.
> SVE cmp<cc>(immediate) instructions can support vector comparing with 7bit unsigned integer immediate (range from 0 to 
> 127)or 5bit signed integer immediate (range from -16 to 15).
> 
> 2. Add optimized match rules to generate the compare-with-immediate instructions.
> 
> [1]: https://developer.arm.com/documentation/ddi0596/2021-12/SVE-Instructions/CMP-cc---immediate---Compare-vector-to-immediate-

Chang Peng has updated the pull request incrementally with one additional commit since the last revision:

  Refactor some code

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13200/files
  - new: https://git.openjdk.org/jdk/pull/13200/files/8a9a43d9..d9d861ea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13200&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13200&range=01-02

  Stats: 111 lines in 4 files changed: 42 ins; 28 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/13200.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13200/head:pull/13200

PR: https://git.openjdk.org/jdk/pull/13200