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breadth-14: LoopStream capability

Agent report: partial Review pending

Session: completed

docs/spec-fabric-reconfigurable-op.md, lines 884–891

A concrete `LoopStream` resource has a closed typed capability containing: * a non-empty set of scalar signless integer widths; * exactly one fixed `dataflow::StreamStepKind`; * a non-empty set of supported `mlir::arith::CmpIPredicate` values; * exact physical operand and result roles; and * its resource-state, use-pattern, holding, timing, and progress contract.

Execution provenance

The original pilot recorded the compiler hash and checkout revision separately; its binary build revision was not verified. Coverage follow-ups use separately identified rebuilt binaries. Original simulator binary hashes were not retained.

Original standalone-test agent report

This is exploratory evidence, not an accepted production-format PBT.

No author explanation recorded.

Reported numeric verdicts

by mutation

bad predicate

PASS

10

bad step kind

PASS

9

controlled violation

FAIL

1

empty predicates

PASS

6

empty widths

PASS

8

extra field

PASS

3

extra operand

INFO

6

extra result

INFO

5

missing operand

INFO

7

missing predicates

PASS

2

missing result

INFO

2

missing step kind

PASS

7

missing widths

PASS

6

none

PASS

13

wrong phase width

INFO

7

zero width

PASS

9

Tested obligations

• closed capability: unknown hw_params field rejected ('hw_params contains unknown field')
• closed capability: missing required field rejected (integer_widths / step_kind / predicates)
• non-empty set of scalar signless integer widths (empty rejected; width 0 rejected as unsupported)
• exactly one fixed dataflow::StreamStepKind (missing rejected; non-vocabulary spelling rejected)
• non-empty set of arith::CmpIPredicate values (empty rejected; non-vocabulary spelling rejected)
• well-formed capabilities across 8 step kinds, 10 predicates, widths {1,8,16,32,64} are accepted

Untested obligations

• clause

  exact physical operand and result roles

  observations

  27 arity/port-width mutation cases recorded as INFO (subject accepted them at parse+verify)

  reason

  not enforced at the fabric.op verifier interface; role/arity admission lives in the TechMapping path (lib/Fabric/IR/ImplementationFamily.cpp:1475), which requires a mapping interface not exercised within budget

• clause

  resource-state, use-pattern, holding, timing, and progress contract

  reason

  runtime/scheduling claim; needs a real timing API or trace, not parsing

Format

Reproduction

Measured subject code coverage

pending · Instrumented coverage follow-up in progress; original pilot did not collect profiles.

Coverage-preserving minimized cases: not measured

Published evidence