Undef MemoryFence, which is defined to _mm_mfence by winnt.h

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295014 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Support/Atomic.h b/include/llvm/Support/Atomic.h
index d03714b009c513f8b093c2cdc152f74d5d1409bc..552313f0c2412bfebc895832ac06d8159f607497 100644 (file)
--- a/include/llvm/Support/Atomic.h
+++ b/include/llvm/Support/Atomic.h
@@ -20,6 +20,11 @@
 
 #include "llvm/Support/DataTypes.h"
 
+// Windows will at times define MemoryFence.
+#ifdef MemoryFence
+#undef MemoryFence
+#endif
+
 namespace llvm {
   namespace sys {
     void MemoryFence();