diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index fa3460810b1..ed9ceb52f3b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -505,7 +505,8 @@ GCC Warnings:
   script:
     # build-ubuntu puts us in `build`.
     - printf "\e[0Ksection_start:%s:cmake_section[collapsed=true]\r\e[0KRunning CMake" "$( date +%s)"
-    - CC=gcc CXX=g++ cmake -DENABLE_EXTRA_COMPILER_WARNINGS=on -DCMAKE_EXPORT_COMPILE_COMMANDS=on -DENABLE_CCACHE=ON -G Ninja ..
+    # Test release build.
+    - CC=gcc CXX=g++ cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_EXTRA_COMPILER_WARNINGS=on -DCMAKE_EXPORT_COMPILE_COMMANDS=on -DENABLE_CCACHE=ON -G Ninja ..
     - printf "\e[0Ksection_end:%s:cmake_section\r\e[0K" "$( date +%s)"
     - script --command ninja --flush --quiet --return ../gcc_report.txt
     - ansi2html < ../gcc_report.txt > ../gcc_report.html