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MIR move elimination [2/6]: TailCopyToMove - #163336
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Some changes occurred to MIR optimizations cc @rust-lang/wg-mir-opt |
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LLM disclosure: I actually tried getting an LLM to write this entire pass for me. It was a disaster that was unsound in new and interesting ways. That draft was promptly nuked and replaced with a properly thought out implementation. LLMs were also used to generate the boilerplate for the MIR tests, but each test was manually reviewed and adjusted before committing. |
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Rollup merge of #163336 - Amanieu:move-elimination/tail-copy-to-move, r=tmiasko MIR move elimination [2/6]: TailCopyToMove Depends on #163335 This PR implements a pre-pass for the `MoveElimination` pass from rust-lang/rfcs#3943. `TailCopyToMove` turns `Copy` into `Move` just before a `Return` terminator. This is valid even for places that have been borrowed because the `Return` will invalidate borrows anyway. This is necessary to allow the source of the copy to be unified with the return place. r? tmiasko
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Depends on #163335
This PR implements a pre-pass for the
MoveEliminationpass from rust-lang/rfcs#3943.TailCopyToMoveturnsCopyintoMovejust before aReturnterminator. This is valid even for places that have been borrowed because theReturnwill invalidate borrows anyway. This is necessary to allow the source of the copy to be unified with the return place.r? tmiasko