Bypass the dispatch chain for inline-value comparison#70
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UBig/IBig ordering went through as_sign_typed -> TypedReprRef::cmp, which materialises slice references even for inline (<= DoubleWord) values. Add Repr::magnitude_cmp (compares inline values as a single DoubleWord, falls through to length-then-words for heap) and Repr::signed_cmp (adds sign handling on top, using the canonical-positive-zero invariant). UBig::cmp now calls magnitude_cmp directly (capacities are always positive) and IBig::cmp calls signed_cmp. cmp_in_place gains #[inline]. The existing cmp / num_order tests exercise every branch (mixed inline/heap operands and both signs). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Directly exercises magnitude_cmp / signed_cmp on equal-scale-different-value pairs and the inline/heap boundary, for both UBig and IBig, rather than relying on incidental coverage from the existing cmp tests. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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I think this problem needs more investigation. I have written a whole bunch of |
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Optimisations for order comparisons that bypass expensive operations on the fast path. Gives a 22-26% speedup on some of my benchmarks.
Benchmarks (layout-sampled, K=11)
Wall-clock, dashu-only, vs the merge base, measured under 11 randomised function layouts (
ld64 -order_file) and reported as the median — to average out the ±10% code-placement noise that otherwise swamps these small-value micro-benchmarks. The untouchedubig_mulcontrol reads 0.0% ± 0.0%, confirming a clean run.ubig_cmp(all classes)ubig_min(one/two-word)ubig_mul(control)