diff --git a/repos/libports/lib/mk/libc-string.mk b/repos/libports/lib/mk/libc-string.mk
index 74128c27bf..ac787cbf29 100644
--- a/repos/libports/lib/mk/libc-string.mk
+++ b/repos/libports/lib/mk/libc-string.mk
@@ -16,6 +16,8 @@ SRC_C = $(filter-out $(FILTER_OUT),$(notdir $(wildcard $(LIBC_STRING_DIR)/*.c)))
 # prevent the generation of a 'memset()' call in 'memset()'
 CC_OPT_memset += -fno-tree-loop-distribute-patterns
 
+override CC_OLEVEL := -O3
+
 include $(REP_DIR)/lib/mk/libc-common.inc
 
 vpath %.c $(LIBC_STRING_DIR)