RFR: 8373722: [TESTBUG] compiler/vectorapi/TestVectorOperationsWithPartialSize.java fails intermittently

[Jie Fu]

On Wed, 24 Dec 2025 09:19:55 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

> Yeah, I'm trying to extend the value range to `1~3000`. The tests are still running... Since the result largely depends on the random values, I run this test `500` times on SVE/NEON/X86 machines respectively (**1500** times totally), and have not observed failure now. Is that fine to you? I will update the test once all tests pass. Thanks for looking at this change!

As with range `1~3000`, we may still see failures even with 1000ULP according to the following program, right?


class T {
  public static void main(String[] args) {

    float ROUNDING_ERROR_FACTOR_ADD = 1000.0f;

    Float a = 1.0f + (ROUNDING_ERROR_FACTOR_ADD + 1) * Math.ulp(1.0f);
    Float b = 3000.0f;

    Float expected = a + b - b;
    Float actual   = a + (b - b);

    float tolerance = Math.ulp(expected) * ROUNDING_ERROR_FACTOR_ADD;
    if (Math.abs(expected - actual) > tolerance) {
      System.out.println("Error: Out of tolerance!");
    }
  }
}

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PR Review Comment: https://git.openjdk.org/jdk/pull/28960#discussion_r2645836521