RFR: 8354473: Incorrect results for compress/expand tests with -XX:+EnableX86ECoreOpts

[Emanuel Peter]

On Tue, 15 Apr 2025 03:54:09 GMT, Volodymyr Paprotski <vpaprotski at openjdk.org> wrote:

> It looks like the `permv` mask isnt always 'all-ones' or 'all-zeroes'. (Which is OK for real blend, but needs to be enforced via the flag for blend emulation)
> 
> Before the fix, `make test TEST="jdk/incubator/vector"` (on ECore machine)
> 
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR  SKIP
>>> jtreg:test/jdk/jdk/incubator/vector                  83    71    10     0     2 <<
> ==============================
> TEST FAILURE
> 
> After the fix:
> 
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR  SKIP
>    jtreg:test/jdk/jdk/incubator/vector                  83    81     0     0     2
> ==============================
> TEST SUCCESS
> 
> And on an AVX512 machine:
> 
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR  SKIP
>    jtreg:test/jdk/jdk/incubator/vector                  83    81     0     0     2
> ==============================
> TEST SUCCESS

@vpaprotsk Can you please give a little more details about what exactly went wrong here, and why your change is correct?

@jatin-bhateja You should probably review this code, since you wrote the code originally :)

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

PR Comment: https://git.openjdk.org/jdk/pull/24645#issuecomment-2823854369