RFR: 8298632: [TESTBUG] Add IR checks in jtreg vectorization tests

[Pengfei Li]

On Thu, 15 Dec 2022 20:23:16 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> In JDK-8183390, we introduced a new auto-vectorization testing framework in hotspot jtreg tests. The new framework provides us a much simpler way to add new test cases of auto-vectorizable loops. But the previous patch just added a check of the correctness of the result after vectorization. There is no check about whether the code is vectorized or not.
>> 
>> This patch adds IR checks to verify C2's vectorization ability on test cases inside this framework. With this patch, each test method annotated with `@Test` is verified in two ways. First, it's invoked twice and the return results from the interpreter and C2 compiled code are compared. Second, the count of expected vector IR is checked by the IR framework if the test method has IR rule annotation.
>> 
>> Ideally, we should check IR rules on all platforms. But in practice, the vectorization ability can be quite different on different platforms, or different generations of CPUs of one platform. So in this patch, we only add vectorizable checks for AArch64. Checks for other platforms (such as x86) can still be added later with more CPU feature conditions. We also add some negative rules (or in-vectorizable rules) with `@IR(failOn=...` on cases that should not be vectorized on any platform.
>> 
>> A few more test cases are added within this patch as well.
>> 
>> We tested the new IR rules on below kinds of CPUs.
>> - AArch64 w/ 512-bit SVE
>> - AArch64 w/ 128-bit SVE
>> - AArch64 w/o SVE (NEON only)
>> - x86
>
> Don't forget to change `applyIfCPUFeature` to `applyIfCPUFeatureOr`
> 
> And to run these tests with different AVX configuration we need to remove `vm.flagless` from `@requires`. `-XX:UseAVX=n` flag is supported by IR testing now.

Hi @vnkozlov ,

Thanks for your review and test. I have made below changes based on your comments.

- Add `avx2` rules for x86 according to your instructions
- Reduce `SIZE` (some test code is updated to align with the reduced `SIZE`)

> And to run these tests with different AVX configuration we need to remove vm.flagless from `@requires`.

Unfortunately, for now we cannot remove `vm.flagless` from `@requires`. As these test methods are also used for correctness check (each test method is invoked twice and the return results from the interpreter and C2 compiled code are compared) and we are using compiler control via WhiteBox API to force these methods running in interpreter and C2. The compiler control won't work if some extra vm option is specified.

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PR: https://git.openjdk.org/jdk/pull/11687