Make AtomicBool the same size as bool #32365
Conversation
|
(rust_highfive has picked a reviewer for you, use r? to override) |
|
The impl looks okay to me. The comment regarding CAS loop also seems to be true, and LLVM won’t accept something like |
|
I'd be a little nervous to land this ahead of rust-lang/rfcs#1543 and rust-lang/rfcs#1505, but it seems fine to me in principle. I'm tagging with |
alexcrichton
added
the
T-libs-api
|
The libs team discussed this during triage yesterday, and some of our discussion led to some surprising conclusions, but in general we felt a little uncomfortable merging this ahead of rust-lang/rfcs#1543. In light of that, we're thinking that we may want to hold off on this for now until we move on one of those RFCs |
|
Ok, we discussed this again in light of accepting rust-lang/rfcs#1543, but we concluded that we probably don't want to do this at this time due to the uncertainty about what to do with platform-specific types. We can certainly revisit this though once the types become stable! |
|
I don't think platform-specific types are relevant here since any platform that supports pointer-sized atomics will always support byte-sized atomics. Changing the size of AtomicBool to 1 byte will therefore not introduce any compatibility issues. |
Add integer atomic types Tracking issue: #32976 RFC: rust-lang/rfcs#1543 The changes to AtomicBool in the RFC are not included, they are in a separate PR (#32365).
Make AtomicBool the same size as bool Reopening #32365 This allows `AtomicBool` to be transmuted to a `bool`, which makes it more consistent with the other atomic types. Note that this now guarantees that the atomic type will always contain a valid `bool` value, which wasn't the case before (due to `fetch_nand`). r? @alexcrichton
This allows
AtomicBoolto be transmuted to abool, which makes it more consistent with the other atomic types. Note that this now guarantees that the atomic type will always contain a validboolvalue, which wasn't the case before (due tofetch_nand).