Document why the volatile read is used

rust-lang · Mar 26, 2019 · 3b6b489 · 3b6b489
1 parent 1ea57aa
commit 3b6b489
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/src/libcore/hint.rs b/src/libcore/hint.rs
@@ -122,6 +122,7 @@ pub fn black_box<T>(dummy: T) -> T {
             )
         )
     )] {
+        // asm.js and emscripten do not support inline assembly
         unsafe {
             let ret = crate::ptr::read_volatile(&dummy);
             crate::mem::forget(dummy);