perf(array): pack Boolean output during RowFn dense retry

[connortsui20]

Stacked on #9988, which adds the CI benchmark without changing production code.

Summary

Routes deferred Boolean dense attempts through the packed collector, preserving the requested multiversioning flag. Keeps the source and failure accumulator in one borrowed state, and inlines the collector's scalar tail so LLVM can retain the alias information needed to vectorize the row loop. Decode errors remain terminal, and null-only failures still retry valid rows.

The earlier x86 regressions came from scalarized collector loops. Optimized Linux IR and the native CI executables confirm that these loops now vectorize.

Changes

Native CI medians in microseconds per eight 16,384-row batches, with partial validity and the multiversioned collector:

Target	Columns before → after	Constant LHS before → after
AVX2	111.0 → 44.53	217.1 → 34.58
AVX-512	42.81 → 45.07	206.9 → 37.25
NEON	68.32 → 71.01	173.3 → 57.62

Constant RHS also improves on every target. Small column-only movements remain uncertain after one paired run. All final cases are below 1 ms, with a maximum printed sample of 555.8 µs.

Passed 175 RowFn tests, 14 Boolean packing tests, and scoped Clippy. The CodSpeed check flags no Boolean retry regressions, but remains red on three other, unattributed benchmark alerts. This remains a draft.

Four-stage comparison, compiler evidence, and raw results. Evidence stays on the separate branch.

[codspeed]

Merging this PR will regress 2 benchmarks

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ 3 benchmarks measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. These results are not comparable, so they count as unchanged.

Preventing compiler optimizations

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 15 improved benchmarks
❌ 2 regressed benchmarks
✅ 2215 untouched benchmarks
⏩ 329 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	take_fsl_random[128, 10]	32.7 µs	58.4 µs	-44.05%
❌	WallTime	filtered_sink_i64_avx2[OneNullInEight]	22 µs	26 µs	-15.53%
⚡	WallTime	deferred_bool_avx2[16384, (ConstantLhs, PartialAccepted)]	206.4 µs	33.9 µs	×6.1
⚡	WallTime	deferred_bool_avx512[16384, (ConstantLhs, PartialAccepted)]	206.3 µs	38.3 µs	×5.4
⚡	Simulation	take_fsl_u32_random[64, 100]	96 µs	30.3 µs	×3.2
⚡	WallTime	deferred_bool_neon[16384, (ConstantLhs, PartialAccepted)]	169.8 µs	54.4 µs	×3.1
⚡	WallTime	deferred_bool_avx2[16384, (Columns, PartialAccepted)]	110.4 µs	43 µs	×2.6
⚡	Simulation	take_fsl_nullable_random[256, 10]	105.5 µs	49.1 µs	×2.1
⚡	Simulation	take_fsl_f16_random[256, 100]	141.2 µs	87.8 µs	+60.89%
⚡	WallTime	deferred_bool_avx2[16384, (ConstantLhs, NullOnlyFailure)]	452.8 µs	282.5 µs	+60.27%
⚡	WallTime	deferred_bool_avx512[16384, (ConstantLhs, NullOnlyFailure)]	452.8 µs	303.7 µs	+49.12%
⚡	WallTime	decode_avx512[8192, (Inline, OneNullInEight)]	111 µs	83.3 µs	+33.27%
⚡	WallTime	deferred_bool_neon[16384, (ConstantLhs, NullOnlyFailure)]	479.5 µs	378.2 µs	+26.77%
⚡	WallTime	deferred_bool_avx2[16384, (Columns, NullOnlyFailure)]	344.2 µs	279.3 µs	+23.27%
⚡	WallTime	decode_avx512[8192, (External, OneNullInEight)]	175.4 µs	152.1 µs	+15.31%
⚡	Simulation	take_fsl_random[64, 100]	143.9 µs	125.3 µs	+14.85%
⚡	Simulation	take_filter_list_nullable_random_mask_random_indices[256, 50]	155.4 µs	138.1 µs	+12.52%
⚠️	Simulation	fixed_16_advancing_ptr_safe[100]	< 1 ns	< 1 ns	N/A
⚠️	Simulation	preverify_advancing_ptr_unchecked[1000]	< 1 ns	< 1 ns	N/A
⚠️	Simulation	preverify_advancing_ptr_unchecked[10000]	< 1 ns	< 1 ns	N/A

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing ct/row-fn-bool-retry (994b7dd) with develop (2c8c7ee)}

Footnotes

1. 329 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩