--- a/make/autoconf/flags.m4	Mon Mar 05 05:50:24 2018 -0800
+++ b/make/autoconf/flags.m4	Tue Mar 06 00:56:03 2018 +0100
@@ -236,7 +236,9 @@
   if test "x$TOOLCHAIN_TYPE" = xxlc; then
     MACHINE_FLAG="-q${OPENJDK_TARGET_CPU_BITS}"
   elif test "x$TOOLCHAIN_TYPE" != xmicrosoft; then
-    MACHINE_FLAG="-m${OPENJDK_TARGET_CPU_BITS}"
+    if test "x$OPENJDK_TARGET_CPU" != xaarch64; then
+      MACHINE_FLAG="-m${OPENJDK_TARGET_CPU_BITS}"
+    fi
   fi
 
   # FIXME: global flags are not used yet...