diff --git a/contrib/check-hard b/contrib/check-hard
index f7c54a7b..00e40f2e 100755
--- a/contrib/check-hard
+++ b/contrib/check-hard
@@ -12,7 +12,7 @@ if [ $CORES -lt 1 ]; then CORES=1; fi
 echo "Running: make distclean"
 make distclean > /dev/null || true
 
-CFLAGS="-std=c89 -pedantic -O2 -g -Wall -Wextra -Wstrict-prototypes -Wold-style-definition -Wwrite-strings -Wshadow -Wformat -Wformat-security -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition"
+CFLAGS="-std=c89 -pedantic -O0 -g -Wall -Wextra -Wstrict-prototypes -Wold-style-definition -Wwrite-strings -Wshadow -Wformat -Wformat-security -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition"
 
 CACHEFILE=$PWD/config_check.cache
 
diff --git a/contrib/travis-ci b/contrib/travis-ci
index 4a07585b..49684435 100755
--- a/contrib/travis-ci
+++ b/contrib/travis-ci
@@ -21,7 +21,7 @@ CORES=3
 
 # Define a large number of Warning flags for the compiler. Hopefully, someone
 # will sit and analyze the output to clean the warnings from the codebase.
-CFLAGS="-std=c89 -pedantic -O2 -Wall -Wextra -Wstrict-prototypes -Wold-style-definition -Wwrite-strings -Wshadow -Wformat -Wformat-security -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition"
+CFLAGS="-std=c89 -pedantic -O0 -Wall -Wextra -Wstrict-prototypes -Wold-style-definition -Wwrite-strings -Wshadow -Wformat -Wformat-security -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition"
 
 # A cachefile for ./configure. Saves significant time when reconfiguring
 CACHEFILE=$PWD/config_check.cache