5.9: [SILOptimizer] Don't optimize move-only lifetimes. #66727
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According to language rules, such lifetimes are fixed and the relative order of their deinits is guaranteed. rdar://110913116
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@swift-ci please test |
tbkka
approved these changes
Jun 19, 2023
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Description: Disable lifetime optimization of instances of move-only types.
The order of deinitialization of such instances are fixed by language rules and can't be altered by optimizations.
Such optimizations could never eliminate any copies of these values regardless.
Risk: Low. The fix is very simple, just bailing at the top level of two utilities.
Scope: Narrow. This only affects move-only types.
Original PR: #66716
Reviewed By: Andrew Trick ( @atrick )
Testing: Added test showing that the utilities don't hoist the destroys of instances of move only structs or enums.
Resolves: rdar://110913116