diff --git a/circle.yml b/circle.yml
index 341b7a7..be236e8 100644
--- a/circle.yml
+++ b/circle.yml
@@ -7,6 +7,12 @@ machine:
 dependencies:
   cache_directories:
     - ~/cmake-3.11.0-Linux-x86_64
+  pre:
+    - wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+    - sudo apt-add-repository "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main"
+    - sudo apt-get update
+    - sudo apt-get install -y clang-5.0
+    - export CXX=clang-5.0
   override:
     - >
       if [ ! -d ~/cmake-3.11.0-Linux-x86_64 ]; then