qiskit/releasenotes/notes/0.24/deterministic-barrier-befor...

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---
fixes:
- |
The :class:`.BarrierBeforeFinalMeasurements` and :class:`.MergeAdjacentBarriers` transpiler
passes previously had a non-deterministic order of their emitted :class:`.Barrier` instructions.
This did not change the semantics of circuits but could, in limited cases where there were
non-full-width barriers, cause later stochastic transpiler passes to see a different topological
ordering of the circuit and consequently have different outputs for fixed seeds. The passes
have been made deterministic to avoid this.