Use Panama Vector API to SIMD-evaluate fixed-cardinality sorted numeric range queries in rangeIntoBitSet()

[costin]

When the stored values have fixed cardinality and no encoding transforms (no gcd, delta, table, or block compression), the vectorization provider loads N values into a SIMD vector, performs a broadcast range check (>= min AND <= max), collapses per-lane results into a per-doc mask, and OR-writes matching docs into the bitset in one operation.

Falls back to scalar when vectorLen % cardinality != 0 (e.g. vpd=8 on AVX2 with 4-lane vectors).

Benchmark

SortedNumericDocValuesRangeQueryBenchmark, 1M docs, cardinality=fixed, density=dense, queryShape=plain. Branch vs main, JDK 25.0.3.

AMD EPYC 7R32 (c5a.2xlarge) — AVX2, 256-bit (4 longs)

SIMD: vpd=2 (2 docs/vec), vpd=4 (1 doc/vec). vpd=8 falls back to scalar.

vpd	pattern	selectivity	baseline (ops/s)	candidate (ops/s)	ratio
2	clustered	0.01	15426.5	15565.0	1.01x
2	clustered	0.1	15331.1	15431.7	1.01x
2	clustered	0.5	19083.7	19168.8	1.00x
2	random	0.01	65.2	134.1	2.06x
2	random	0.1	58.7	95.8	1.63x
2	random	0.5	65.1	86.7	1.33x
4	clustered	0.01	9830.6	9843.3	1.00x
4	clustered	0.1	9676.3	9852.7	1.02x
4	clustered	0.5	18409.4	18256.0	0.99x
4	random	0.01	52.3	70.2	1.34x
4	random	0.1	46.3	49.7	1.07x
4	random	0.5	53.2	64.3	1.21x
8	clustered	0.01	5925.1	5891.1	0.99x
8	clustered	0.1	5830.6	5845.9	1.00x
8	clustered	0.5	17669.9	17599.9	1.00x
8	random	0.01	42.1	43.7	1.04x
8	random	0.1	38.6	40.9	1.06x
8	random	0.5	44.2	50.2	1.14x

Intel Xeon 8375C (c6i.2xlarge) — AVX-512, 512-bit (8 longs)

SIMD: vpd=2 (4 docs/vec), vpd=4 (2 docs/vec), vpd=8 (1 doc/vec).

vpd	pattern	selectivity	baseline (ops/s)	candidate (ops/s)	ratio
2	clustered	0.01	19255.8	19439.4	1.01x
2	clustered	0.1	18689.0	19133.6	1.02x
2	clustered	0.5	22700.0	22745.1	1.00x
2	random	0.01	83.3	208.4	2.50x
2	random	0.1	67.6	133.4	1.97x
2	random	0.5	65.7	127.8	1.94x
4	clustered	0.01	11715.4	11658.7	1.00x
4	clustered	0.1	11791.0	11727.0	0.99x
4	clustered	0.5	20998.0	21080.8	1.00x
4	random	0.01	63.5	104.1	1.64x
4	random	0.1	50.9	65.9	1.29x
4	random	0.5	61.5	94.7	1.54x
8	clustered	0.01	7133.1	7202.5	1.01x
8	clustered	0.1	6956.8	6995.9	1.01x
8	clustered	0.5	20338.1	20369.2	1.00x
8	random	0.01	47.2	53.5	1.13x
8	random	0.1	43.2	38.1	0.88x
8	random	0.5	51.6	54.1	1.05x

Clustered data shows no change since sequential access is already at L1/L2 cache speed; comparison cost is negligible. Wins appear on random data where per-doc cache misses dominate and SIMD batching amortizes comparison overhead.

Gains scale with docsPerVector: vpd=2 on AVX-512 processes 4 docs per vector (best), vpd=8 on AVX2 falls back to scalar (no gain).

[sgup432]

I don't think creating a separate interface for this specific use case looks right.
It differs from the existing DocValuesRangeSupport only by a single parameter ie cardinality. So doesn't justify creating a new abstraction layer just based on that, probably we can create or add just another method to existing DocValuesRangeSupport? Something like:

default void rangeIntoBitSet(LongValues values,
      int fromDoc,
      int toDoc,
      int cardinality,
      long minValue,
      long maxValue,
      FixedBitSet bitSet,
      int offset) {
      // default to scalar approach.
}

Let me know what you think.

[costin]

Make sense. I've removed the interface in favor of a new method which has the nice benefit of reducing the PR size.

[sgup432]

Have few minor comments. Also I think we should unit tests which cover scenarios with different cardinality values where it is > 1, vectorLen % cardinality != 0 and other cases? Assuming this is not already covered via existing tests.

[costin]

Have few minor comments. Also I think we should unit tests which cover scenarios with different cardinality values where it is > 1, vectorLen % cardinality != 0 and other cases? Assuming this is not already covered via existing tests.

See my other comments. I've parameterized testSortedNumericRangeIntoBitSetVaryingCardinality to exercise the other cardinalities {2, 3, 4, 5, 7, 8} to check both the SIMD and fallback scalar path.

[sgup432]

LGTM!