{"abstract":"Store forwarding crosses an intervening may-alias write.","category":"Compiler transformation correctness","checks":7,"contract":"Return candidate value if every intervening write is proven disjoint; otherwise return None meaning retain the load. Alias facts are no, may, or must.","evaluation_group":"model-ad3c9aff3354803b","failed_approach":"Rejecting must-alias alone treats uncertainty as proof of disjointness.","family":"z-compilers-alias-forward","id":"FA-11481","implementations":{"attempt":{"sha256":"4df2c8e415b063cd17dc1a8a827c2c24adf0c15747ea12c72976bb9284a570ff","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, writes):\n    return None if 'must' in writes else value\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('no writes', solve(N,[]), N)\ncheck('disjoint write', solve(N,['no']), N)\ncheck('must alias', solve(N,['must']), None)\ncheck('may alias', solve(N,['may']), None)\ncheck('may after disjoint', solve(N,['no','may']), None)\ncheck('many disjoint', solve(N,['no']*N), N)\ncheck('must after may', solve(N,['may','must']), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"e0e3a4a3ac9a0fe561b3298092e88c8deb11dec3da76435b593dba11196d9613","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, writes):\n    return value\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('no writes', solve(N,[]), N)\ncheck('disjoint write', solve(N,['no']), N)\ncheck('must alias', solve(N,['must']), None)\ncheck('may alias', solve(N,['may']), None)\ncheck('may after disjoint', solve(N,['no','may']), None)\ncheck('many disjoint', solve(N,['no']*N), N)\ncheck('must after may', solve(N,['may','must']), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"3b469add7944bb189a3ebfefbb3e308b5f6cacfa938e7fe07666232bfae89e74","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, writes):\n    return value if all(a == 'no' for a in writes) else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('no writes', solve(N,[]), N)\ncheck('disjoint write', solve(N,['no']), N)\ncheck('must alias', solve(N,['must']), None)\ncheck('may alias', solve(N,['may']), None)\ncheck('may after disjoint', solve(N,['no','may']), None)\ncheck('many disjoint', solve(N,['no']*N), N)\ncheck('must after may', solve(N,['may','must']), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"z-compilers-alias-forward","generated_at":"2026-09-29T14:38:48.326718+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic miniature compiler-pass model; inputs are explicit IR facts, not a production compiler.","repair":"Invalidate forwarding on must-alias or may-alias intervening writes.","root_cause":"A candidate store value is forwarded without inspecting intervening writes.","sha256":"6dd322966b005961061337880e73ecaf5d2a0cf29c46e1e67c2292a4ee9f808a","title":"Store forwarding crosses an intervening may-alias write · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.395,"exit_code":1,"observations":[{"actual":1,"check":"no writes","expected":1,"passed":true},{"actual":1,"check":"disjoint write","expected":1,"passed":true},{"actual":null,"check":"must alias","expected":null,"passed":true},{"actual":1,"check":"may alias","expected":null,"passed":false},{"actual":1,"check":"may after disjoint","expected":null,"passed":false},{"actual":1,"check":"many disjoint","expected":1,"passed":true},{"actual":null,"check":"must after may","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"no writes\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"disjoint write\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must alias\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"may alias\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"may after disjoint\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"many disjoint\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must after may\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.329,"exit_code":1,"observations":[{"actual":1,"check":"no writes","expected":1,"passed":true},{"actual":1,"check":"disjoint write","expected":1,"passed":true},{"actual":1,"check":"must alias","expected":null,"passed":false},{"actual":1,"check":"may alias","expected":null,"passed":false},{"actual":1,"check":"may after disjoint","expected":null,"passed":false},{"actual":1,"check":"many disjoint","expected":1,"passed":true},{"actual":1,"check":"must after may","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"no writes\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"disjoint write\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must alias\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"may alias\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"may after disjoint\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"many disjoint\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must after may\", \"actual\": 1, \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.995,"exit_code":0,"observations":[{"actual":1,"check":"no writes","expected":1,"passed":true},{"actual":1,"check":"disjoint write","expected":1,"passed":true},{"actual":null,"check":"must alias","expected":null,"passed":true},{"actual":null,"check":"may alias","expected":null,"passed":true},{"actual":null,"check":"may after disjoint","expected":null,"passed":true},{"actual":1,"check":"many disjoint","expected":1,"passed":true},{"actual":null,"check":"must after may","expected":null,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"no writes\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"disjoint write\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must alias\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"may alias\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"may after disjoint\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"many disjoint\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"must after may\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}