RFR: 8324890: C2 SuperWord: refactor out VLoop, make unrolling_analysis static, remove init/reset mechanism [v2]

[Emanuel Peter]

On Thu, 1 Feb 2024 19:21:41 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Emanuel Peter 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 12 additional commits since the last revision:
>> 
>>  - Merge branch 'master' into JDK-8324890
>>  - _vtrace is moved to VLoop
>>  - comment update
>>  - cosmetics
>>  - rename in preconditions
>>  - remove loop_transform_helper
>>  - fix small bug
>>  - preallocate memory
>>  - more refactoring
>>  - moved mark_reductions
>>  - ... and 2 more: https://git.openjdk.org/jdk/compare/ce6bb9ff...25e3710e
>
> Would be nice to see affect of these changes on C2 compilation time. You have to create SW object each time now instead only once.

@vnkozlov I created https://github.com/openjdk/jdk/pull/17683 to add time measurement. Let me try it on a simple benchmark here.

Disabled turbo-boost for benchmark.

**test001,002,003**
`../../../linux-x64/jdk/bin/java -XX:CompileCommand=compileonly,TestAutoVectorizationTime::test0* -Xbatch -XX:+CITime -XX:+UnlockDiagnosticVMOptions -XX:RepeatCompilation=1000 TestAutoVectorizationTime.java`
This patch:

Xbatch:
         IdealLoop:            25.508 s
           AutoVectorize:       5.927 s
Xcomp:
         IdealLoop:            12.860 s
           AutoVectorize:       2.736 s

TODO

**test101**
`../../../linux-x64/jdk/bin/java -XX:CompileCommand=compileonly,TestAutoVectorizationTime::test1* -Xbatch -XX:+CITime -XX:+UnlockDiagnosticVMOptions -XX:RepeatCompilation=100 TestAutoVectorizationTime.java`
This patch:



TODO

**test201**
`../../../linux-x64/jdk/bin/java -XX:CompileCommand=compileonly,TestAutoVectorizationTime::test2* -Xbatch -XX:+CITime -XX:+UnlockDiagnosticVMOptions -XX:RepeatCompilation=100 TestAutoVectorizationTime.java`
This patch:



TODO

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PR Comment: https://git.openjdk.org/jdk/pull/17624#issuecomment-1923533791