Remove duplicate optimization loop in level 3 PassManager #8785
Conversation
For some time (I expect since Qiskit#6403 but maybe before) we've been running the optimization loop for optimization level 3 twice for no reason. This is clearly a mistake as it adds a single extra run of all the optimization passes since we've already reached a steady state in depth and size by this point. This is just a waste of time and was unintentional. This commit removes the unintended duplication.
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To see the difference you can look at the drawn pass manager. Before this PR the generated preset pass manager for level 3 is:
After this PR the duplicate do while loop is removed:
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Heh, well I wish I could claim this would substantial speed things up, in practice it just saves us a couple of dag iterations with no real work being done :) |
Pull Request Test Coverage Report for Build 3115861362
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Summary
For some time (I expect since #6403 but maybe before) we've been running the optimization loop for optimization level 3 twice for no reason. This is clearly a mistake as it adds a single extra run of all the optimization passes since we've already reached a steady state in depth and size by this point. This is just a waste of time and was unintentional. This commit removes the unintended duplication.
Details and comments