From 0f9f241aac21bc77fb9e757da18207abefdc841d Mon Sep 17 00:00:00 2001 From: Sebastian Pop Date: Mon, 5 Apr 2021 17:17:23 +0000 Subject: [aarch64] add target feature outline-atomics Enable outline-atomics by default as enabled in clang by the following commit https://reviews.llvm.org/rGc5e7e649d537067dec7111f3de1430d0fc8a4d11 Performance improves by several orders of magnitude when using the LSE instructions instead of the ARMv8.0 compatible load/store exclusive instructions. Tested on Graviton2 aarch64-linux with x.py build && x.py install && x.py test --- compiler/rustc_codegen_llvm/src/llvm_util.rs | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'compiler/rustc_codegen_llvm/src') diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs index f9172e43773..2d053abd44e 100644 --- a/compiler/rustc_codegen_llvm/src/llvm_util.rs +++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs @@ -416,6 +416,11 @@ pub fn llvm_global_features(sess: &Session) -> Vec { // -Ctarget-features features.extend(sess.opts.cg.target_feature.split(',').flat_map(&filter)); + // FIXME: Move outline-atomics to target definition when earliest supported LLVM is 12. + if get_version() >= (12, 0, 0) && sess.target.llvm_target.contains("aarch64-unknown-linux") { + features.push("+outline-atomics".to_string()); + } + features } -- cgit 1.4.1-3-g733a5