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 27bbaba..6c4da66 100644
--- 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)