diff --git a/gcc/config/aarch64/aarch64-builtins.cc b/gcc/config/aarch64/aarch64-builtins.cc
index 5bb873c3923..611f6dc45e0 100644
--- a/gcc/config/aarch64/aarch64-builtins.cc
+++ b/gcc/config/aarch64/aarch64-builtins.cc
@@ -2321,6 +2321,7 @@ aarch64_init_ls64_builtins_types (void)
   const char *tuple_type_name = "__arm_data512_t";
   tree node_type = get_typenode_from_name (UINT64_TYPE);
   tree array_type = build_array_type_nelts (node_type, 8);
+  array_type = build_distinct_type_copy (array_type);
   SET_TYPE_MODE (array_type, V8DImode);
 
   gcc_assert (TYPE_MODE_RAW (array_type) == TYPE_MODE (array_type));
diff --git a/gcc/testsuite/g++.target/aarch64/pr124126-1.C b/gcc/testsuite/g++.target/aarch64/pr124126-1.C
new file mode 100644
index 00000000000..ffe4fb6690b
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/pr124126-1.C
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-g" } */
+/* PR target/124126 */
+/* Make sure an array of uint64_t[8] works when
+   used before the inlcude of arm_acle.h.  */
+
+typedef unsigned long uint64_t;
+void executeSuperscalar(uint64_t (*r)[8]);
+
+#include "arm_acle.h"
+
+void initDatasetItem() {
+  uint64_t rl[8];
+  executeSuperscalar(&rl);
+}