[robert3005]

A const condition removes the unreachable arms before codegen in three places:

• check_decimal_identical dispatched on the lhs storage type, the rhs storage type and their widest type. The two distinct inputs fix the widest type, so only 30 of 216 arms can run.
• widened_buffer::<W> is only called for storage types narrower than W (all callers pass the wider of two inputs), and the narrowing branch of converted_buffer::<W> only runs for storage types wider than W. Only 15 of 36 arms of each can run.
• The bit-packed widening cast compiled all 64 integer pairs, but only widening pairs reach the kernel.

Bit-packing rejects negative values, so sign extension of a packed value is the same as zero extension. The bit-packed cast now views a signed source as unsigned (the packed buffer is shared and the patch values are reinterpreted) and reinterprets the result to the target type. Signed and unsigned casts of the same widths share one kernel, so the cast compiles 6 kernels instead of 18 reachable ones.

release __text (macOS arm64)	before	after
vortex-array	14,023,548 B	13,933,616 B (-90 KB)
vortex-fastlanes	4,442,156 B	4,331,764 B (-110 KB)

[codspeed]

Merging this PR will regress 1 benchmark

3 warnings, 1 note

⚠️ Walltime results may be unreliable

Some benchmarks used the Walltime instrument outside CodSpeed Macro Runners, which can make the results inconsistent.

Learn more about Macro Runners

See affected benchmarks

⚠️ Unable to measure the execution of 1 benchmark

This benchmark measured no execution time, so its result is not comparable and counts as unchanged. This usually happens when the compiler removes the code under test.

Prevent compiler optimizations

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⚠️ 20 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

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ℹ️ 40 benchmarks have no flamegraph

The flamegraph wasn't generated: the symbols of the profiling trace could not be resolved, because no information about the language frames was collected.

See affected benchmarks

⚡ 8 improved benchmarks
❌ 1 regressed benchmark
✅ 2399 untouched benchmarks
⏩ 12 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Walltime	threshold_avx2[80]	2.6 µs	2.9 µs	-10.54%
⚡	Walltime	filter_neon[8]	1,997 ns	924 ns	×2.2
⚡	Walltime	threshold_neon[8]	2.6 µs	1.3 µs	+96.65%
⚡	Walltime	filter_neon[64]	2.5 µs	1.8 µs	+39.35%
⚡	Walltime	threshold_neon[64]	3.5 µs	2.6 µs	+36.62%
⚡	Walltime	threshold_neon[80]	4.6 µs	3.4 µs	+34.78%
⚡	Walltime	filter_neon[80]	3.4 µs	2.7 µs	+26.32%
⚡	Walltime	decode_chunked_neon[i64, 524288]	15.7 µs	13.4 µs	+17.34%
⚡	CPU Simulation	or_true_constant	20.8 µs	18.8 µs	+10.53%

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 rk/size-unreachable-dispatch-arms (dd90465) with develop (c750fbd)}

Footnotes

1. 12 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. ↩