Item 1 off T53's list. Two changes: the route, and the design flaw underneath it.
THE DEFECT UNDER THE DEFECT (cookbook §106). residual_class answers two questions in one pass:
`klass` is a MEASUREMENT (expensive, from comparing instruction streams); `(profile, bucket)` is a
POLICY (a table lookup over it). autopsy persisted BOTH and verdicts() read BOTH back — so editing
_ROUTE changed nothing until someone re-ran the whole collect, and a weeks-old row could silently
out-vote the live table with no oracle to report it. The corpus on disk is dated Jul 21 and does not
even contain the SESSION-23 targets the recommendation cited.
Fixed by re-deriving at read time: residual_class.route_for(klass, detail), called from
autopsy.verdicts(). R33 — persist the measurement, derive the decision. Subtlety: LENGTH-DRIFT's
route is MAGNITUDE-dependent (permuter only when |delta|<=2 AND explains=="tail", §60b), so a naive
re-derivation from klass alone would have silently demoted 9 rows; both inputs are already in
`detail`, so the override reproduces exactly — VERIFIED 1610/1610 against the stored corpus with the
table UNCHANGED, before touching it.
THE ROUTE CHANGE: ADDRESSING ("cse","permuter") -> ("cse","structural"). It contradicted this file's
own bucket definition ("structural — local mutation CANNOT introduce it ... it wants a C-level
idiom"): the §10/§20 hoist-vs-remat shape is a multi-instruction change with a documented recipe
(gcc-2.7.2-map/cse_expr.md §2, byte-proven on func_80149374/func_801493D0). Measured (T31): both
admitted ADDRESSING targets plateaued under a §31-directed permuter, and the class was 32% of the
admission pool. After: pool 56 -> 38, exactly 18 rows changed, ALL ADDRESSING, nothing else moved;
grinder admits 45, structural skips 512 -> 530.
THE BOUND (R14), kept in the _ROUTE comment: I read the T31 record instead of the summary line, and
the summary was looser than the evidence. T31 finding 4 byte-tested the §2 recipe on func_80132F40
across six variants and it never closed (best 40 mismatches). `structural` does NOT promise a free
fix — it means "a search over local mutations is the wrong tool, try the documented idiom", exactly
what WIDTH / BRANCH-POLARITY / IMM-OFFSET already mean. Also corrected: the checkpoint cited
func_80176734 as the flat-for-32-min evidence, but that function is not in the corpus at all.
Tooling-only: no src/ or config/ change, no bank, no metric move.
Drew T
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