Fix for atomic intrinsics detection when using MSVC.

Patch by Michael Beck!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90683 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/cmake/modules/CheckAtomic.cmake b/cmake/modules/CheckAtomic.cmake
index 27bbaba6998c99416a56a151ffd8cbf697216d17..6c4da66bfadea3a3e5d84af58d53377c93b4dc6c 100644 (file)
--- a/cmake/modules/CheckAtomic.cmake
+++ b/cmake/modules/CheckAtomic.cmake
@@ -1,14 +1,26 @@
 # atomic builtins are required for threading support.
 
 INCLUDE(CheckCXXSourceCompiles)
+
+#ifdef _MSC_VER
+#include <windows.h>
+#endif
        
 CHECK_CXX_SOURCE_COMPILES("
 int main() {
+#ifdef _MSC_VER
+        volatile LONG val = 1;
+        MemoryBarrier();
+        InterlockedCompareExchange(&val, 0, 1);
+        InterlockedIncrement(&val);
+        InterlockedDecrement(&val);
+#else
         volatile unsigned long val = 1;
         __sync_synchronize();
         __sync_val_compare_and_swap(&val, 1, 0);
         __sync_add_and_fetch(&val, 1);
         __sync_sub_and_fetch(&val, 1);
+#endif
         return 0;
       }
 " LLVM_MULTITHREADED)