8342387: C2 SuperWord: refactor and improve compiler/loopopts/superword/TestDependencyOffsets.java

[eme64]

I want to refactor TestDependencyOffsets.java using the CompileFramework.

Reasons:

• I soon need to modify the IR rules in this test soon anyway (https://github.com/openjdk/jdk/pull/21521), and so a refactor might be good to do first.
• The generator script used to be a generator.py, stored not on git but JBS. Not great. Now we have it in Java code, and maintenance is easier.
• Since I first wrote that test, I have now introduced the IRNode.VECTOR_SIZE. This allows:
  • Simplifying the logic for the IR rules (removed the IRRange and IRBool, and the Platform).
  • Strengthening the rules.
• I was able to add random offsets. This means we have better coverage, and do not rely on just hand-crafted values.

I extensively use String.format and StringBuilder... would be nicer to have string-templates but they don't exist yet.

Recommendation for review: the old file was huge. Finding the new code in the diff can be hard. I would start by only reading the new file.

Ah. And about runtime of the test. On my machine I get this (in ms):

Generate: 27
Compile:  5845
Run:      23435

Test generation is negligible. 6sec on compilation, 20+sec on execution. I think that is an ok balance, at least we can say that generation and compilation only take about 1/6 of total time - an acceptable overhead I would say.

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Progress

• [x] Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• [x] Change must not contain extraneous whitespace
• [x] Commit message must refer to an issue

Issue

• JDK-8342387: C2 SuperWord: refactor and improve compiler/loopopts/superword/TestDependencyOffsets.java (Enhancement - P4)

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)
• Christian Hagedorn (@chhagedorn - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/21541/head:pull/21541
$ git checkout pull/21541

Update a local copy of the PR:
$ git checkout pull/21541
$ git pull https://git.openjdk.org/jdk.git pull/21541/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 21541

View PR using the GUI difftool:
$ git pr show -t 21541

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/21541.diff

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