Fr0zka
34f06dfea7
Jahni's call to pin it and move on, and the right one -- six builds spent and the information stopped being worth the cost. The final run closed it as far as it can be: SDFs identical everywhere (counted unconditionally, 0 differ), yet two character-identical carve implementations in the SAME translation unit fed a provably identical input differ by 1 ULP on 126/5000. That is only possible if they compile to different instruction sequences, which /fp:fast permits based on surrounding context with no single isolable axis. Hypothesis 3 was right about the mechanism and wrong about every clean variable proposed for it, which is why four well-designed isolation tests came back negative. AUDIT C10 records the observation, what is proven (SDF bit-exact 126/126, zero isosurface crossings), the five refuted hypotheses in a table so nobody repeats them at a build each, why the settling experiment is blocked (shared-PCH / IWYU debt), and the rule that actually matters: never run both density paths in one world and never compare them for equality. That is NOT a client-desync risk -- within a binary the field is proven bit-pure and every peer runs the same path -- the cross-platform concern is C9, which stands on its own. Corrected OPSTACK-PLAN 2.6 and C9: my earlier "/fp:fast across translation units" explanation was measurably wrong and is removed rather than softened. MazeEquivalence keeps the permanent value (equivalence with ULP grading, window-invariance, box-verdict brute force) and drops the verbatim copy, three-way, bisect, inlining and constness experiments. Phase 1 closed: Maze decomposes into 7 ops, SDF bit-exact, 0 isosurface crossings, window-invariant, and 23 of 60 tiles proved uniform where ClassifyTile proves zero. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>