diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 6107062c0111..46d87310220d 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -49,7 +49,8 @@ endif
 
 ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
 # Generic build system uses -O2, we want -O3
-cflags-y  += -O3
+# Note: No need to add to cflags-y as that happens anyways
+ARCH_CFLAGS += -O3
 endif
 
 # small data is default for elf32 tool-chain. If not usable, disable it