RFR: 8256438: AArch64: Implement match rules with ROR shift register value [v2]

[Eric Liu]

> This patch transforms '(x >>> rshift) + (x << lshift)' into
> 'RotateRight(x, rshift)' during GVN phase when both the shift exponents
> are constants and their sum equals to the number of bits for the type
> of shift base.
> 
> This patch implements some new match rules for AArch64 instructions
> which can take ROR as the optional shift. Such instructions are 'and',
> 'or', 'eor', 'eon', 'bic' and 'orn'.
> 
>   ror     w11, w2, #5
>   eor     w0, w1, w11
> 
> With this patch, above code could be optimized to below:
> 
>   eor     w0, w1, w2, ror #5
> 
> Finally, the patch refactors TestRotate.java[1][2].
> 
> Tested jtreg TestRotate.java, hotspot::hotspot_all_no_apps,
> jdk::jdk_core, langtools::tier1.
> 
> [1] https://bugs.openjdk.java.net/browse/JDK-8252776
> [2] https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-September/039911.html

Eric Liu has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into 8256438
   
   Change-Id: Ia357074efc8488a57030863b3eab7b27839cd3d0
 - 8256438: AArch64: Implement match rules with ROR shift register value
   
   This patch transforms '(x >>> rshift) + (x << lshift)' into
   'RotateRight(x, rshift)' during GVN phase when both the shift exponents
   are constants and their sum equals to the number of bits for the type
   of shift base.
   
   This patch implements some new match rules for AArch64 instructions
   which can take ROR as the optional shift. Such instructions are 'and',
   'or', 'eor', 'eon', 'bic' and 'orn'.
   
     ror     w11, w2, #5
     eor     w0, w1, w11
   
   With this patch, above code could be optimized to below:
   
     eor     w0, w1, w2, ror #5
   
   Finally, the patch refactors TestRotate.java[1][2].
   
   Tested jtreg TestRotate.java, hotspot::hotspot_all_no_apps,
   jdk::jdk_core, langtools::tier1.
   
   [1] https://bugs.openjdk.java.net/browse/JDK-8252776
   [2] https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-September/039911.html
   
   Change-Id: I70842bcdb7cbc31bdf261c3223ea882076c2c66b

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1858/files
  - new: https://git.openjdk.java.net/jdk/pull/1858/files/6135975d..afc68c27

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1858&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1858&range=00-01

  Stats: 116364 lines in 2912 files changed: 46136 ins; 41070 del; 29158 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1858.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1858/head:pull/1858

PR: https://git.openjdk.java.net/jdk/pull/1858