[PATCH] D157765: [llvm langref] inaccessiblemem implies nosync

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

TBH I find the semantics of nosync to be unclear to the point of uselessness, and I'm not sure whether this patch helps clarify them any.

I think the two clarifications to `nosync` that would help are:

- The memory effects of a synchronizing operation include all memory effects that the synchronization can make visible. For example, a synchronizing operation that can make previous writes to a location visible must have a write memory effect for that location.
- A synchronizing operation that imposes an ordering constraint with other synchronizing operations must perform a read and write to inaccessible memory.

I think this matches how LLVM models synchronization, but I was never able to get really satisfactory answer to this.


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https://reviews.llvm.org/D157765