RFR: 8309697: [TESTBUG] Remove "@requires vm.flagless" from jtreg vectorization tests

[Vladimir Kozlov]

On Tue, 25 Jul 2023 08:35:11 GMT, Pengfei Li <pli at openjdk.org> wrote:

> This patch removes `@require vm.flagless` annotations from HotSpot jtreg tests in `compiler/vectorization/runner`. All jtreg cases in this folder are invoked by test driver `VectorizationTestRunner.java` which checks both correctness and vectorizability (IR) for each test method. We added flagless requirement before because extra flags may mess with compiler control in the test driver for correctness check. But `flagless` has a side effect that it makes tests with extra flags skipped. So we propose to get rid of it now.
> 
> To adapt the removal of `@require vm.flagless`, a few checks are added in the test driver to skip the correctness check if extra flags make the compiler control not work. This patch also moves previously hard-coded flag `-XX:-OptimizeFill` in the test driver to conditions in IR checks.
> 
> Tested various of compiler control related VM flags on x86 and AArch64.

test/hotspot/jtreg/compiler/vectorization/runner/VectorizationTestRunner.java line 69:

> 67:         boolean use_comp = WB.getBooleanVMFlag("UseCompiler");
> 68:         boolean bg_comp = WB.getBooleanVMFlag("BackgroundCompilation");
> 69:         if (use_intp && use_comp && bg_comp) {

Why you check `BackgroundCompilation`?
For `-Xcomp` you need only check `UseInterpreter`.
Xor `-Xint` you need only check `UseCompiler`.

test/hotspot/jtreg/compiler/vectorization/runner/VectorizationTestRunner.java line 144:

> 142:                 // We skip the correctness check in this case.
> 143:                 System.out.println("WARNING: Correctness check is skipped because C2 compilation times out");
> 144:                 return;

Why not run with `BackgroundCompilation` OFF? The code will return from `WHITE_BOX.enqueueMethodForCompilation()` only after finishing compiling or compiler skip.
Compilation speed is very different on different platform. Using time for check is not reliable.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15011#discussion_r1275334642
PR Review Comment: https://git.openjdk.org/jdk/pull/15011#discussion_r1275344975