From 4dc4e9f671a36026cf59894622fdf4f6b979bf76 Mon Sep 17 00:00:00 2001
From: Lzu Tao <taolzu@gmail.com>
Date: Wed, 16 Sep 2020 09:25:54 +0000
Subject: [PATCH] Fix black_box bug detected by Amanieu

Co-authored-by: Amanieu <amanieu@gmail.com>
---
 library/core/src/hint.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/core/src/hint.rs b/library/core/src/hint.rs
index 929c22e4538f..1192b9e164a1 100644
--- a/library/core/src/hint.rs
+++ b/library/core/src/hint.rs
@@ -122,7 +122,7 @@ pub fn black_box<T>(mut dummy: T) -> T {
     // SAFETY: the inline assembly is a no-op.
     unsafe {
         // FIXME: Cannot use `asm!` because it doesn't support MIPS and other architectures.
-        llvm_asm!("" : : "r"(&mut dummy));
+        llvm_asm!("" : : "r"(&mut dummy) : "memory" : "volatile");
     }
 
     dummy