diff --git a/Makefile b/Makefile
index 471cf59..c473092 100644
--- a/Makefile
+++ b/Makefile
@@ -256,9 +256,14 @@
 				-Wvla
 
 ifeq ($(findstring clang,$(notdir $(CC))),)
+# not using clang
 WARNINGS	+=		-Wunused-but-set-variable	\
 				-Wmaybe-uninitialized		\
-				-Wpacked-bitfield-compat
+				-Wpacked-bitfield-compat	\
+				-Wshift-overflow=2
+else
+# using clang
+WARNINGS	+=		-Wshift-overflow -Wshift-sign-overflow
 endif
 
 ifneq (${E},0)