1 files changed, 4 insertions, 1 deletions
diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
index 7f3345d2a70..3b6808d693f 100644
--- a/compiler/rustc_llvm/build.rs
+++ b/compiler/rustc_llvm/build.rs
@@ -276,7 +276,10 @@ fn main() {
         "stdc++"
     };
 
-    // RISC-V requires libatomic for sub-word atomic operations
+    // RISC-V GCC erroneously requires libatomic for sub-word
+    // atomic operations. FreeBSD uses Clang as its system
+    // compiler and provides no libatomic in its base system so
+    // does not want this.
     if !target.contains("freebsd") && target.starts_with("riscv") {
         println!("cargo:rustc-link-lib=atomic");
     }