[all-commits] [llvm/llvm-project] b1b108: [ARM] Add target feature to force 32-bit atomics
Nikita Popov via All-commits
all-commits at lists.llvm.org
Wed Jul 27 01:02:57 PDT 2022
Author: Nikita Popov <npopov at redhat.com>
Date: 2022-07-27 (Wed, 27 Jul 2022)
[ARM] Add target feature to force 32-bit atomics
This adds a +atomic-32 target feature, which instructs LLVM to assume
that lock-free 32-bit atomics are available for this target, even
if they usually wouldn't be.
If only atomic loads/stores are used, then this won't emit libcalls.
If atomic CAS is used, then the user is responsible for providing
any necessary __sync implementations (e.g. by masking interrupts
for single-core privileged use cases).
See https://reviews.llvm.org/D120026#3674333 for context on this
change. The tl;dr is that the thumbv6m target in Rust has
historically made atomic load/store only available, which is
incompatible with the change from D120026, which switched these to
Differential Revision: https://reviews.llvm.org/D130480
More information about the All-commits