diff --git a/.travis.yml b/.travis.yml
index 257de66e0..36df67052 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,7 +17,7 @@ matrix:
     - env: Cmd='make gcc6install libc6install
              && make clean && CC=gcc-6 make -j uasan-test-zstd32'
     - env: Cmd='make gcc7install && make clean && CC=gcc-7 make -j uasan-test-zstd'
-    - env: Cmd='make gcc8install && CC=gcc-8 CFLAGS=-Werror make -j all'
+    - env: Cmd='make gcc8install && CC=gcc-8 CFLAGS="-Werror -O3" make -j all'
     - env: Cmd='make clang38install && CC=clang-3.8 make clean msan-test-zstd'
 
     - env: Cmd='make gcc6install && CC=gcc-6 make clean uasan-fuzztest'