Use indexed sources for fallible constant rows

[connortsui20]

Summary

• Tracking Issue: Epic: Row-oriented scalar functions #9128

RowFn handles constant inputs so row kernels do not need separate execution paths for each input shape. #9628 adds an indexed source for infallible execution, but fallible execute_owned still uses a separate loop whenever any input is constant. That loop selects between row and constant values on every iteration, duplicating the traversal and hiding the fixed batch input shape from LLVM.

Depends on #9628.

Changes

Extends the decoded indexed source to fallible execute_owned calls. Each source validates its decoded length and fixes its row-or-constant behavior before traversal, allowing every input shape to use map_checked_into without changing output initialization or deferred failure handling.

This removes the separate LaneZip branch. Optimized x86 IR preserves the vector loop while reducing the focused deferred Boolean executor by 27% and the deferred i64 executor by 19%, with the same bounds-panic sites. Tests cover a constant left-hand input, and the focused benchmark covers varying inputs and both partial-constant orientations.

[codspeed-hq]

Merging this PR will regress 1 benchmark

⚠️ 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.

⚠️ 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

⚡ 8 improved benchmarks
❌ 1 regressed benchmark
✅ 2121 untouched benchmarks
🆕 9 new benchmarks
⏩ 106 skipped benchmarks¹
🗄️ 4 archived benchmarks run²

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	mul_i8_nonnull_avx2	11.2 µs	12.9 µs	-13.05%
⚡	WallTime	mul_u64_nonnull_neon	20.6 µs	15.4 µs	+34.05%
⚡	WallTime	multiply_shapes_neon[(16384, PerRowPerRow)]	20.6 µs	17.2 µs	+19.92%
⚡	WallTime	mul_i64_nonnull_neon	20.2 µs	17.1 µs	+18.49%
⚡	WallTime	multiply_shapes_neon[(128, PerRowPerRow)]	2.2 µs	1.9 µs	+16.32%
⚡	WallTime	add_shapes_neon[(128, PerRowPerRow)]	2.1 µs	1.8 µs	+12.17%
⚡	WallTime	multiply_shapes_neon[(16384, PerRowConstant)]	22.8 µs	20.3 µs	+12.11%
⚡	WallTime	subtract_shapes_neon[(128, PerRowPerRow)]	2.1 µs	1.8 µs	+12.06%
⚡	WallTime	multiply_shapes_neon[(16384, PerRowNullableConstant)]	23.3 µs	21.1 µs	+10.34%
🆕	WallTime	deferred_i64_neon[ConstantPerRow]	N/A	16.6 µs	N/A
🆕	WallTime	deferred_i64_neon[PerRowConstant]	N/A	16.7 µs	N/A
🆕	WallTime	deferred_i64_neon[PerRowPerRow]	N/A	15.6 µs	N/A
🆕	WallTime	deferred_i64_avx512[ConstantPerRow]	N/A	10.1 µs	N/A
🆕	WallTime	deferred_i64_avx512[PerRowConstant]	N/A	10.1 µs	N/A
🆕	WallTime	deferred_i64_avx512[PerRowPerRow]	N/A	10 µs	N/A
🆕	WallTime	deferred_i64_avx2[ConstantPerRow]	N/A	10.2 µs	N/A
🆕	WallTime	deferred_i64_avx2[PerRowConstant]	N/A	10.1 µs	N/A
🆕	WallTime	deferred_i64_avx2[PerRowPerRow]	N/A	10 µs	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-execute-owned-sources (0dcfaae) with develop (42a5d3b)}

Footnotes

1. 106 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. ↩

2. 4 benchmarks were run, but are now archived. If they were deleted in another branch, consider rebasing to remove them from the report. Instead if they were added back, click here to restore them. ↩