diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 502b08f2714daab0b77ab61e3c2f9e28b22347d9..739ffb4fab7b9f71ecb93450e7beb4d125c8c3a3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,6 +4,13 @@ default:
   # Image from https://hub.docker.com/_/gcc/ based on Debian
   image: gcc
 
+whitespace:
+  stage: test
+  only:
+    - merge_requests
+  script:
+    - git diff-tree --check origin/master HEAD
+
 autoconf:
   stage: build
   before_script: