RFR: 8325438: Add exhaustive tests for Math.round intrinsics [v9]

[Hamlin Li]

On Tue, 9 Apr 2024 13:55:22 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> [foo.zip](https://github.com/openjdk/jdk/files/14919424/foo.zip)
>
> Does that work for you?

Thanks for the sample code.

I modify the current test a bit by using your code, i.e. change from 2 level nested loop to single while loop as below, let's call it `new test`

  @Test
  static boolean test(int testInt) {
        float testFloat = Float.intBitsToFloat(testInt);
        return Math.round(testFloat) != golden_round(testFloat);
  }

  @Run(test = "test")
  static void test_rounds(RunInfo runInfo) {
    for (int i = 0; i < 1000; i++) {        
        test(i);
    }
    if (runInfo.isWarmUp()) {
        return;
    }
    boolean runTest = true; // modify here to have try.
    if (!runTest) return;
    int testInt = 0;
    boolean fail = false;
    do {
        fail |= test(testInt);
    } while (++testInt != 0);
    if (fail) {
        throw new RuntimeException();
    }
  }


It still took more than 5 minutes to finish the test; if I assign `runTest = false`, it will take seconds. So most of time is spent on the while loop in `test_rounds` with `@Run` annotation in new test, I'm not sure how the annotation @Run works, but seems that's the reason why it's slower than a pure while loop (in your sample code). But we need the annotations in the test (check below).
There are still some gaps between this new test and current test:
* we still not yet verify IR Node (`IRNode.ROUND_VF`); to verify it, we need to put the (part of) test into a nested loop, and put this loop in a function (`test_round` in current test), and annotate this function with `@IR` to verify the IR node.

Or maybe there are other ways to implement this test and qualify below requirements? Currently I'm not sure.
1. run in a minute, as we want it to be an automatic test,
2. verify Math.round (intrinsic) result,
3. verify IR node (`IRNode.ROUND_VF) generation,
4. make sure all the verification is done after the warmup.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/17753#discussion_r1557906817