mirror of
https://github.com/rust-lang/rust.git
synced 2025-10-27 11:05:06 +00:00
095ca33bb6
nontemporal_store: make sure that the intrinsic is truly just a hint The `!nontemporal` flag for stores in LLVM *sounds* like it is just a hint, but actually, it is not -- at least on x86, non-temporal stores need very special treatment by the programmer or else the Rust memory model breaks down. LLVM still treats these stores as-if they were normal stores for optimizations, which is [highly dubious](https://github.com/llvm/llvm-project/issues/64521). Let's avoid all that dubiousness by making our own non-temporal stores be truly just a hint, which is possible on some targets (e.g. ARM). On all other targets, non-temporal stores become regular stores. ~~Blocked on https://github.com/rust-lang/stdarch/pull/1541 propagating to the rustc repo, to make sure the `_mm_stream` intrinsics are unaffected by this change.~~ Fixes https://github.com/rust-lang/rust/issues/114582 Cc `@Amanieu` `@workingjubilee`