What should we add?

Over the course of the epic:

• Track adding control flow passes for optimization level 1 #8630

we added support for control-flow to the transpiler at optimisation levels 0 and 1. For full support, we need to bring the missing passes up-to-speed as well. This epic tracks the other components to achieve that.

For the purposes of this issue, we particularly need SabreSwap upgrading. For optimisation level 2, we need the optimisation passes CommutationAnalysis and CommutativeCancellation, and optimisation level 3 (and some less common transpiler options) make up the rest. We do not need to add support for control-flow to all of the scheduling passes right now, because Qiskit control-flow is only supported by IBM hardware at the moment, and scheduling this is handled by the IBM provider.

When these are updated, we should also make sure that the corresponding gated checks in the preset pass-manager constructors are corrected.

Sub-epics:

• Enable control flow in optimization_level=2 #9431
• Enable control flow in optimization_level=3 #9432

Tracked issues:

• Support control flow in SabreSwap #9419
• Support control flow in Python components of SabreLayout #9421
• Restore level 1 layout/routing default to SabreSwap #9422
• Support control flow in CommutationAnalysis and CommutativeCancellation #9423
• Support control flow in DAGCircuit.collect_runs #9425
• Support control flow in ConsolidateBlocks #9426

Low priority related issues - these should not be prioritised, and are not required for this epic:

• Support control flow in LookaheadSwap #9429
• Support control flow in BasicSwap #9430