diff --git a/ci/appveyor/appveyor.yml b/ci/appveyor/appveyor.yml
index 0cae78027b..2122153494 100644
--- a/ci/appveyor/appveyor.yml
+++ b/ci/appveyor/appveyor.yml
@@ -7,3 +7,4 @@ after_build:
   - '%APPVEYOR_BUILD_FOLDER%\ci\appveyor\after_build.bat'
 cache:
   - 'llvm+clang-5.0.1-win64-msvc-release.tar.xz'
+  - 'llvm+clang-6.0.0-win64-msvc-release.tar.xz'