diff --git a/gcc/config/aarch64/aarch64-c.cc b/gcc/config/aarch64/aarch64-c.cc
index 578ec6f45b06347d90f951b37064006786baf10f..ab8844f6049dc95b97648b651bfcd3a4ccd3ca0b 100644
--- a/gcc/config/aarch64/aarch64-c.cc
+++ b/gcc/config/aarch64/aarch64-c.cc
@@ -82,6 +82,7 @@ aarch64_update_cpp_builtins (cpp_reader *pfile)
 {
   aarch64_def_or_undef (flag_unsafe_math_optimizations, "__ARM_FP_FAST", pfile);
 
+  cpp_undef (pfile, "__ARM_ARCH");
   builtin_define_with_int_value ("__ARM_ARCH", AARCH64_ISA_V9A ? 9 : 8);
 
   builtin_define_with_int_value ("__ARM_SIZEOF_MINIMAL_ENUM",
diff --git a/gcc/testsuite/gcc.target/aarch64/armv9_warning.c b/gcc/testsuite/gcc.target/aarch64/armv9_warning.c
new file mode 100644
index 0000000000000000000000000000000000000000..35690d5bce790e11331788aacef00f3f35cdf216
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/armv9_warning.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-march=armv9-a -Wpedantic -Werror" } */
+
+#include <arm_neon.h>
+