gh-144569: Avoid creating temporary objects in BINARY_SLICE for bytes - #156318
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koxudaxi wants to merge 3 commits into
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gh-144569: Avoid creating temporary objects in BINARY_SLICE for bytes#156318koxudaxi wants to merge 3 commits into
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koxudaxi
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August 24, 2026 14:37
cocolato
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Python/optimizer_bytecodes.c
cocolato
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Aug 26, 2026
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@markshannon gentle ping, please take a look at this if you have time, thanks! |
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Add an exact bytes fast path to BINARY_SLICE, following the list, tuple, and unicode fast paths added in gh-144590. This avoids creating a temporary slice object. Bytes subclasses continue to use the generic path.
Teach the Tier 2 optimizer that slicing an exact bytes object returns an exact bytes object.
Benchmark
Release builds on macOS arm64. Each result is the median of nine alternating runs after two warmups. Each sample ran in a fresh process.
There was no measurable change in peak RSS.
Tests
The full debug test suite passed with 50,671 tests using 14 workers.
Focused tests passed on debug, free-threaded, and JIT builds. test_bytes and test_slice also passed a -R 3:3 refleak run.