6.0: [MoveOnlyAddressChecker] Don't complete reborrows or their adjacent phis. #73359
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After 874971c, before running address checking, all lifetimes in the function are completed. That doesn't quite work because lifetime completion expects not to encounter reborrows or their adjacent phis.
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@swift-ci please test |
tbkka
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May 1, 2024
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Explanation: Fix a compiler crash caused by completing certain lifetimes during move checking.
Move-only checking relies on the completeness of lifetimes of interest. Way back in #68381 , a change was made to run lifetime completion in functions continaing move-only values; only values obviously derived from the value being checked had their lifetimes completed. Much more recently, in 874971c, an analogous change was made to complete lifetimes in functions containing move-only addresses; in the recent patch, though, rather than trying to find all the values that could be derived from the address being checked, all lifetimes in the function were completed. This doesn't quite work, though, because lifetime completion doesn't know how to deal with reborrows--it's intended to be run in a SIL prior to reborrows existing.
Here, the lifetimes that are completed in functions with move-only addresses are trimmed back to exclude values whose lifetimes depend on reborrows.
Scope: Affects noncopyable code.
Issue: rdar://127312637
Original PR: #73358
Risk: Low. Decreases the cases in which a SIL transformation is run.
Testing: Added regression test.
Reviewer: Andrew Trick ( @atrick )