qat.experimental.conversion.pulse_to_q1.loop_fission module

Fission a shot loop into one copy per frame lineage.

A shot loop drives every frame in the program, so it belongs to every lineage at once and cannot be attributed to a single outlined sequence. Qblox runs one program per sequencer, each with its own loop, so the loop is replicated.

Only scf.for is handled. It is the sole region-bearing operation the importer puts in a Pulse entry block, so it is the only shape that needs splitting today. Anything else enclosing more than one lineage is rejected rather than guessed at, since splitting it would need rules for its regions and block arguments that nothing yet exercises.

The copy carries no values between iterations. An scf.for can pass a value from one iteration to the next through iter_args, and the importer uses that to accumulate acquisitions into a results array. A sequencer has no equivalent: acquisitions land in hardware bins, and the bin index is recomputed from the loop counter when the acquire is lowered. The array is bookkeeping with no hardware counterpart, so the copy simply does not have it.

fission_for_lineage(op, lineage, analysis, value_mapper)

Build a copy of an scf.for with only the contents belonging to lineage.

Parameters:

  • op (Operation) – Shot loop enclosing the work of one or more lineages.

  • lineage (FrameLineage) – Lineage whose work the returned copy carries.

  • analysis (FrameLineageAnalysis) – Analysis providing per-operation lineage ownership.

  • value_mapper (dict[SSAValue, SSAValue]) – Clone mapping for the partition, used to resolve operands defined by entry-block operations already copied into this sequence.

Return type:

ForOp

Returns:

A newly built scf.for carrying only lineage’s operations, with no loop-carried values.

Raises:

PassFailedException – If op is not an scf.for, if the loop has an unsupported shape, or if the copy would have to carry a loop-carried value.

is_results_op(op)

Return whether op is a results-dialect operation.

Results operations are bookkeeping with no hardware counterpart, so they are dropped from emitted sequences. Membership is tested against the dialect’s registered operations.

Parameters:

op (Operation) – Operation to classify.

Return type:

bool

Returns:

True if op belongs to the results dialect.