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6fa6a854cd
atomicrmw on pointers: move integer-pointer cast hacks into backend Conceptually, we want to have atomic operations on pointers of the form `fn atomic_add(ptr: *mut T, offset: usize, ...)`. However, LLVM does not directly support such operations (https://github.com/llvm/llvm-project/issues/120837), so we have to cast the `offset` to a pointer somewhere. This PR moves that hack into the LLVM backend, so that the standard library, intrinsic, and Miri all work with the conceptual operation we actually want. Hopefully, one day LLVM will gain a way to represent these operations without integer-pointer casts, and then the hack will disappear entirely. Cc ```@nikic``` -- this is the best we can do right now, right? Fixes https://github.com/rust-lang/rust/issues/134617
The codegen crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc dev guide.