diff --git a/src/common/cpu.c b/src/common/cpu.c
index e3335f2bd..9f38f07ce 100644
--- a/src/common/cpu.c
+++ b/src/common/cpu.c
@@ -110,6 +110,8 @@ int ValidAddrSizeForCPU (unsigned char AddrSize)
 
         default:
             FAIL ("Invalid address size");
+            /* NOTREACHED */
+            return 0;
     }
 }