From 89582e8193e0da64a54c4ffae7f9fa64ed9fe2af Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov@redhat.com>
Date: Wed, 27 Jul 2022 14:26:00 +0200
Subject: Pass +atomics-32 feature for thumbv6m target

https://reviews.llvm.org/D120026 changed atomics on thumbv6m to
use libatomic, to ensure that atomic load/store are compatible with
atomic RMW/CAS. However, Rust wants to expose only load/store
without libcalls.

https://reviews.llvm.org/D130480 added support for this behind
the +atomics-32 target feature, so enable that feature.
---
 compiler/rustc_codegen_llvm/src/llvm_util.rs | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'compiler/rustc_codegen_llvm')

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index a0a640473eb..96d238eda59 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -440,6 +440,8 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
             .features
             .split(',')
             .filter(|v| !v.is_empty() && backend_feature_name(v).is_some())
+            // Drop +atomics-32 feature introduced in LLVM 15.
+            .filter(|v| *v != "+atomics-32" || get_version() >= (15, 0, 0))
             .map(String::from),
     );
 
-- 
cgit 1.4.1-3-g733a5