diff --git a/.travis.yml b/.travis.yml
index 466f47c8c7c..74cd5a530f7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,6 +12,12 @@ matrix:
       cache: false
     - sudo: 9000
       dist: trusty
+      before_install:
+        - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
+        - sudo add-apt-repository 'deb http://apt.llvm.org/precise/ llvm-toolchain-precise-3.9 main' -y
+        - sudo apt-get update -q
+        - sudo apt-get install clang-3.9 llvm-3.9 llvm-3.9-runtime -y
+        - export LLVM_CONFIG=/usr/lib/llvm-3.9/bin/llvm-config
       script:
          - ./mach build -d --verbose
          - ./mach test-compiletest