Module block 

Basic block: a straight-line sequence of quantum gate instructions.

A BasicBlock is the primary container for gate sequences in the Libket IR. It maintains an index of qubit read/write dependencies that is used by the qubit-mapping pass, and it applies lightweight algebraic optimizations (gate merging and cancellation) whenever a new instruction is appended.

Gate simplification

When a new gate is appended, the block scans backwards through the existing instruction list for the first instruction that shares any qubit:

• If the two instructions have the same target and controls and are inverses of each other, both are cancelled (removed).
• If they have the same target and controls and are on the same rotation axis, their parameters are added and emitted as a single merged gate.
• If neither simplification applies, the gate is appended unconditionally.

Structs

BasicBlock

A straight-line sequence of quantum gate instructions.

QubitOp

Per-qubit dependency record maintained by a BasicBlock.