diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 3ddbc6ba041..9ac1ce9a357 100644
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -47,11 +47,16 @@
 /// \macro LLVM_MSC_PREREQ
 /// \brief Is the compiler MSVC of at least the specified version?
 /// The common \param version values to check for are:
-///  * 1600: Microsoft Visual Studio 2010 / 10.0
 ///  * 1700: Microsoft Visual Studio 2012 / 11.0
 ///  * 1800: Microsoft Visual Studio 2013 / 12.0
 #ifdef _MSC_VER
 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
+
+// We require at least MSVC 2012.
+#if !LLVM_MSC_PREREQ(1700)
+#error LLVM requires at least MSVC 2012.
+#endif
+
 #else
 #define LLVM_MSC_PREREQ(version) 0
 #endif