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.
The autopsy (hindsight-study §7) assumed the permuter loses for want of a mutation.
Measured over the whole open backlog, it loses because it is aimed at work a
search-closer provably cannot close.
- NEW tools/residual_class.py: decide a near-miss's class FROM THE BYTES. Decodes each
mismatching MIPS word -> (op-skeleton, register-fields, immediate); drift FIRST (one
inserted insn inflates `closeness` by the tail length), then consistent-injective
register map -> REGALLOC-PERM (§31 S11/RC-3), same-multiset-reorder -> SCHEDULE-REORDER,
DELAY-SLOT, WIDTH/BRANCH-POLARITY/STRENGTH/ADDRESSING/IMM-OFFSET/IMM-VALUE. Every class
routes to a BUCKET = which tool the failure wants. Uncovered opcode -> UNKNOWN, COUNTED
(R32). 16 synthetic unit tests (test_residual_class.py).
- NEW tools/autopsy.py: `collect` materialises the corpus Task-12's telemetry never filled
(1 of 6,169 records had a residual) by recompiling every open draft through the EXISTING
match_one path (R33) — 1,752 drafts in 21s at -j12. `report` -> docs/autopsy.md.
- NEW corpus.o0_sources()/is_o0(): the opt-level oracle DERIVED from the Makefile's own -O0
rules, coverage-asserted. Scoring an -O0 target at -O2 makes the residual 100% artefact
(the trap this phase hit four times).
- R34 cross-check baked in: residual_class's closeness vs masked_diff.structured_diff's,
asserted per row; 1,673/1,673 agree, 0 classifier errors.
FINDING: of the 972 records the grinder's own filter admits, only 75 (7.7%) are
permuter-shaped; 547 are structural and 348 are drafts that are not the function at all.
~92% of the daemon's CPU went where it could not win — the byte-grounded explanation of
"7 banks all-time, all Phase 21, 0 since" (Phase-22 audit). grinder.candidates() now
filters on the measured bucket (1,303 -> 78) and takes its directed profile from the
measured class, not the logged label (91% carry none -> it ran on gcc defaults).
Degrades to undirected if uncollected and says so; --no-targeting A/Bs it.
Two measured corollaries (R14, not projections):
- 699 records rank as near-misses at closeness up to 278 purely from a length artefact:
un-attempted work misfiled as a backlog of hard functions -> new `redraft` bucket.
- a 12-draft gate probe of the `integration` bucket banked 1/12 (11 PLUMBING), so the 306
prices Task 14's reconcile ladder rather than promising free banks. func_80167714
(104 ins, reach-134) banked x1, un-propagated by design (§55b).
Two defects fixed forward:
- masked_diff._common_typedefs() used ONE shared probe path, so parallel match_one
processes clobbered each other: 14 of 1,752 drafts lost in a single 12-way run (0.8%),
silently, in every parallel wave ever run. Now per-PID.
- gate_stage.match_one_closeness never passed --o0 -> phantom residuals for every -O0
function, written straight into the backlog this autopsy reads.
R22 clean-fleet: check-all 140 passed, 0 failed of 140; tools-health OK (dedup 1847/0,
C1 234343/234343); 0 NON_MATCHING (G4). Flywheel captured in-session (R30/R31):
cookbook §60, decision-log entry, SETUP.md inventory.
Drew T