Fix order preservation in align_right #6899
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align_right
was implemented as e.g.reverse(align_left(reverse(circuit.moments)))
. However this did not guarantee order preservation for non-commuting operations in the same moment. Reversing the circuit's moments did not reverse the ops within those moments. The subsequentalign_left
could split those ops into separate moments. Then reversing the moments again would have the end result of swapping the order of those operations in the final circuit.This PR ensures order is preserved, by making sure to reverse the order of ops within each moment prior to the call to
align_left
and re-reversing them prior to returning.Fixes #6727