RFR: 8370370: Add still more cases to WorstCaseTests [v2]

[Raffaello Giulietti]

On Thu, 23 Oct 2025 02:24:36 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> Add additional worst-case tests from a new preprint of a paper examining the Julia numerical environment, which uses a fork of FDLIBM.
>
> Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add more test cases.

I don't know why there are so many discrepancies, but there might be good reasons.
I just blindly used the values in Table 10 of the Julia preprint.

So take the comments with care.

test/jdk/java/lang/Math/WorstCaseTests.java line 200:

> 198:             {+0x1.48ae5a67204f5p+0,     +0x1.ffd10abffc3fep-3},
> 199:             // Julia worst-case observed error
> 200:             {+0x1.14fad2c09e275p0,      +0x1.42a13ec2691dbp-4},

Suggestion:

            {+0x1.14fad2c09e275p0,      +0x1.42a13ec2691dcp-4},

test/jdk/java/lang/Math/WorstCaseTests.java line 301:

> 299:             {-0x1.004d1c5a9400bp-1,     -0x1.0c6e322e8a28bp-1},
> 300:             // Julia worst-case observed error
> 301:             {-0x1.012d405d9408ep-1,     -0x1.0d7142df4968fp-1},

Suggestion:

            {-0x1.012d405d9408ep-1,     -0x1.0d7142df4969p-1},

test/jdk/java/lang/Math/WorstCaseTests.java line 394:

> 392:             {-0x1.0068b067c6feep-1,     +0x1.0c335e2f0726fp1},
> 393:             // Julia worst-case observed error
> 394:             {-0x1.0b7c63033d6cp-1,      +0x1.0f6c7f5db3b93p1},

Suggestion:

            {-0x1.0b7c63033d6cp-1,      +0x1.0f6c7f5db3b94p1},

test/jdk/java/lang/Math/WorstCaseTests.java line 613:

> 611: 
> 612:             // Julia worst-case observed error, 1.9 ulps
> 613:             // {0x1.8633c654fee2bp-831,    +0x1.fdf25fc26e7cp1023},

Suggestion:

            // {-0x1.633c654fee2bap9,    +0x1.fdf25fc26e7cp1023},

test/jdk/java/lang/StrictMath/CubeRootTests.java line 474:

> 472:             {0x0.0000ffffffff8p-1022,   0x1.ffffffffaaaabp-347},
> 473:             {0x0.0fffffffffffbp-1022,   0x1.fffffffffffcbp-343},
> 474:             {-0x1.0edb6c7fa500fp-531,   -0x1.04dc0b189b6cep-177}, // next down from Julia value

Suggestion:

            {-0x1.0edb6c7fa500fp-531,   -0x1.04dc0b189b6cfp-177}, // next down from Julia value

test/jdk/java/lang/StrictMath/HyperbolicTests.java line 475:

> 473: 
> 474:              // Julia worst-case input
> 475:             {0x1.0108b83c4bbc8p-1,      0x1.dad53a45da5b0p-2},

Suggestion:

            {0x1.0108b83c4bbc8p-1,      0x1.dad53a45da5b2p-2},

test/jdk/java/lang/StrictMath/Log1pTests.java line 212:

> 210:             {0x1.d42aea2878b45p328,     0x1.c7e96ee5c7f87p7},
> 211:             {0x1.249ad2594989p332,      0x1.cc845b54b54a6p7},
> 212:             {0x1.300240b87b096p-4,      0x1.25417bd05ba95p-4}, // nextUp from Julia value

Suggestion:

            {0x1.300240b87b096p-4,      0x1.25417bd05ba94p-4}, // nextUp from Julia value

test/jdk/java/lang/StrictMath/TrigTests.java line 276:

> 274: 
> 275:             // Julia worst-case input
> 276:             {0x1.e608f1390d9fp293,  -0x1.9942a10545925p-1},

Suggestion:

            {0x1.e608f1390d9fp293,  -0x1.9942a10545924p-1},

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

PR Review: https://git.openjdk.org/jdk/pull/27939#pullrequestreview-3383531328
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465696830
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465697254
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465697566
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465697948
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465698122
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465698406
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465699811
PR Review Comment: https://git.openjdk.org/jdk/pull/27939#discussion_r2465700194