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The Rust memory model is deviating from it a little in order to enable some norestrict-based optimizations that aren't really done for C, even though (as you kn
by Jweb_Guru 6y ago
The Rust memory model is deviating from it a little in order to enable some norestrict-based optimizations that aren't really done for C, even though (as you know) LLVM can't really take advantage of them yet.
- staticassertion 6y agoI imagine that in C if the compiler can prove that two pointers don't alias than it can elide a load?
- pjmlp 6y agoIt is very much compiler specific, and also depends if modifiers like volatile are present or not.
- Jweb_Guru 6y agoSure, or with C++ TBAA it can do that too, but those rules work differently from the kinds of guarantees that Rust's type system provides. The C equivalent is (sort of) restrict, but it's used very rarely--so no one has really worked out what its semantics would be like if it were used at the same scale it is in Rust, and there are a lot of bugs.