Downgrade build system error message to a warning

Instead of requiring MSVC 2013 U4, we simply warn users, since some might
not bt able to immediately upgrade.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229598 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index 24af2f81ceb3b1b09699f497f257bc50391f23ab..ba6114a4f567a1f851b8ccd6772a818fa6e05cae 100644 (file)
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -41,8 +41,11 @@ int main() { return (float)x; }"
       set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
     endif()
   elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0.31101)
-      message(FATAL_ERROR "Host Visual Studio must be at least 2013 Update 4 (MSVC 18.0.31101)")
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0)
+      message(FATAL_ERROR "Host Visual Studio must be at least 2013")
+    elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0.31101)
+      message(WARNING "Host Visual Studio should at least be 2013 Update 4 (MSVC 18.0.31101)"
+        "  due to miscompiles from earlier versions")
     endif()
   endif()
 endif()