Strengthen C++20 SC accesses #2512
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☔ The latest upstream changes (presumably #2455) made this pull request unmergeable. Please resolve the merge conflicts. |
RalfJung
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Aug 27, 2022
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Thanks! LGTM, apart from the comment. |
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@bors r+ |
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☀️ Test successful - checks-actions |
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@SabrinaJewson noted in #2301 that Miri could produce behaviours forbidden under C++20 even without SC fences. Due to the added coherence-ordered before relationship which is created from read from and read before, plus the fact that coherence-ordered before between SC operations must be consistent with the Global Total Order S, in C++20 if there's an SC load that reads from any store, then a later SC load cannot read before that store. This PR adds this restriction