From 2ddc96c9e5a86e3fd12954b3efc269f0cc8d07d8 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 17 Jun 2018 18:06:24 +0000
Subject: [PATCH] make WMB / MB safer on x86-64

make it so that

if (foo)
	RMB;
else
	MB;

is always done correctly and without syntax surprises
---
 common_x86_64.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/common_x86_64.h b/common_x86_64.h
index 3236778b8..62e138e34 100644
--- a/common_x86_64.h
+++ b/common_x86_64.h
@@ -61,11 +61,11 @@
 */
 
 #ifdef __GNUC__
-#define MB __asm__ __volatile__("": : :"memory")
-#define WMB __asm__ __volatile__("": : :"memory")
+#define MB do { __asm__ __volatile__("": : :"memory"); } while (0)
+#define WMB do { __asm__ __volatile__("": : :"memory"); } while (0)
 #else
-#define MB
-#define WMB
+#define MB do {} while (0)
+#define WMB do {} while (0)
 #endif
 
 static void __inline blas_lock(volatile BLASULONG *address){