diff --git a/arch/arm/src/armv8-m/arm_cache.c b/arch/arm/src/armv8-m/arm_cache.c
index dde0d71daaa..543d4b90492 100644
--- a/arch/arm/src/armv8-m/arm_cache.c
+++ b/arch/arm/src/armv8-m/arm_cache.c
@@ -90,6 +90,7 @@
  *
  ****************************************************************************/
 
+#ifdef CONFIG_ARMV8M_DCACHE
 static inline uint32_t arm_clz(unsigned int value)
 {
   uint32_t ret;
@@ -97,6 +98,7 @@ static inline uint32_t arm_clz(unsigned int value)
   __asm__ __volatile__ ("clz %0, %1" : "=r"(ret) : "r"(value));
   return ret;
 }
+#endif
 
 /****************************************************************************
  * Public Functions