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[Wall time +0.01% vs main; mixed repeat directions] Index macro arms lazily by their first literal token - #157

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[Wall time +0.01% vs main; mixed repeat directions] Index macro arms lazily by their first literal token#157
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perf-review-20260907/44-macro-first-token-rule-index-fixed

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@xmakro xmakro commented Sep 7, 2026

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Extend the first-token filter with an ordered lazy rule index, retaining fallback arms, original precedence and complete diagnostic replay.

Comparison Wall time Instructions Peak RSS
Complete PR vs main +0.012% -0.560% -0.286%
Profile, complete PR vs main Wall time
check -0.071%
debug +0.121%
opt -0.013%

Negative percentages mean less elapsed time or fewer resources. The title is an individual local timing estimate; small changes may be measurement noise.

The two recorded repetitions give aggregate timing estimates of +0.077% and -0.053% for the title comparison. Mixed directions are marked in the title. This repeatability check is not a confidence interval.

Both compilers use the same source base, CI LLVM, fixed standard libraries, ThinLTO and jemalloc. Each has separate nine-workload Rust PGO training. The stock collector measures all 20 Primary benchmarks: 249 Check/Debug/Opt and full/incremental cases, two observations per compiler per case, alternating baseline/candidate order by crate. No other campaign builds run during measurement. Percentages are equal-case geometric means. LLVM retraining and BOLT are omitted.

This branch has one commit directly on main. Its exact measured source passed the full UI and incremental suites plus the additional suites recorded in the build provenance.

Required support copied without the other optimizations: Tracker flag and token equality visibility from PR 141; no scalar arm filter.

Fixed main commit: da47efd27287edb02eed0b5a178a165c8f258e37. Measured source patch SHA-256: 3494435518fdcb7c2fc39af7bedb3d47fc14d0cd3cf4d616837e10d29dd46e39.

Local raw measurements and per-case CSVs: independent-pr157-main-v1-comparison.csv in the September 6 investigation directory. Build/test provenance: pgo/independent-pr157-source-timing-v1/provenance.json.

@xmakro xmakro changed the title [0.187% fewer Debug instructions, screen] Index macro arms lazily by their first literal token [Debug instructions -0.187%; isolated reused PGO screen] Index macro arms lazily by their first literal token Sep 8, 2026
@xmakro
xmakro force-pushed the perf-review-20260907/43-external-module-negative-cache branch from 3ceaae5 to 5e03967 Compare September 9, 2026 06:21
@xmakro
xmakro force-pushed the perf-review-20260907/44-macro-first-token-rule-index-fixed branch from b9439c5 to 0df282c Compare September 9, 2026 06:21
@xmakro xmakro changed the title [Debug instructions -0.187%; isolated reused PGO screen] Index macro arms lazily by their first literal token [Wall time +0.01% vs main; mixed repeat directions] Index macro arms lazily by their first literal token Sep 9, 2026
@xmakro
xmakro changed the base branch from perf-review-20260907/43-external-module-negative-cache to main September 9, 2026 06:22
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