[vectorIntrinsics+fp16] RFR: 8302454: Improve VectorAPI fallback implementation for FP16 operations.

[Jatin Bhateja]

On Thu, 16 Feb 2023 05:03:53 GMT, Swati Sharma <duke at openjdk.org> wrote:

> Hi All,
> 
> The patch contains the below changes:
> - Remove redundant Halffloat object creation and rebase existing implementation using Float.float16ToFloat and floatToFloat16 APIs.
> - Enable all the vector API tests for FP16 operations.
> 
> Please review and provide your feedback.
> 
> Thanks,
> Swati

test/jdk/jdk/incubator/vector/templates/Unit-Miscellaneous.template line 249:

> 247:         }
> 248: #if[Halffloat]
> 249:        // assertBroadcastLongArraysEquals(r, a, b, mask, $vectorteststype$::blend);

Assertion needs to be uncommented.

test/jdk/jdk/incubator/vector/templates/Unit-Miscellaneous.template line 632:

> 630: #else[Halffloat]
> 631:         VectorSpecies species = vsh.withLanes($type$.class);
> 632: #end[Halffloat]

You can save adding special handling in template by introducing a new template-variable

test/jdk/jdk/incubator/vector/templates/Unit-header.template line 1063:

> 1061:             withToString("Halffloat[i * 5]", (int s) -> {
> 1062:                 return fill(s * BUFFER_REPS,
> 1063:                             i -> Halffloat.valueOf(i * 5));

You can move the specialization part of lambda into a separate routine, it will prevent replicating the GENERATOR code.

test/jdk/jdk/incubator/vector/templates/Unit-header.template line 1139:

> 1137:             withToString("Halffloat[i + 1]", (int s) -> {
> 1138:                 return fill(s * BUFFER_REPS,
> 1139:                             i -> ((($type$)(i + 1) == 0) ? Halffloat.valueOf(1) : Halffloat.valueOf(i + 1)));

Code replication  can be saved by moving specialization into a new routine

test/jdk/jdk/incubator/vector/templates/X-LoadStoreTest.java.template line 251:

> 249:         for (int i = 0; i < a.length; i++) {
> 250: #if[Halffloat]
> 251:             ms.set(ValueLayout.JAVA_SHORT, i * SPECIES.elementSize() / 8 , a[i]);

Try removing conditions as suggested above.

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PR: https://git.openjdk.org/panama-vector/pull/211