From 0bccd2d7e777ab5bd758b5e07e1917872876660d Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Thu, 2 Oct 2025 15:00:56 -0500
Subject: [PATCH v1 1/1] disallow big endian on aarch64

---
 configure    | 7 +++++++
 configure.ac | 7 +++++++
 meson.build  | 4 ++++
 3 files changed, 18 insertions(+)

diff --git a/configure b/configure
index 22cd866147b..249474ac891 100755
--- a/configure
+++ b/configure
@@ -14999,6 +14999,13 @@ _ACEOF
 fi
 
 
+# AArch64 is bi-endian, but we require little
+if test x"$host_cpu" = x"aarch64"; then
+  if test x"$ac_cv_c_bigendian" = x"yes"; then
+    as_fn_error $? "big endian is not supported for aarch64" "$LINENO" 5
+  fi
+fi
+
 # MSVC doesn't cope well with defining restrict to __restrict, the
 # spelling it understands, because it conflicts with
 # __declspec(restrict). Therefore we define pg_restrict to the
diff --git a/configure.ac b/configure.ac
index e44943aa6fe..5b95a0adf5c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1685,6 +1685,13 @@ PGAC_UNION_SEMUN
 AC_CHECK_TYPES(socklen_t, [], [], [#include <sys/socket.h>])
 PGAC_STRUCT_SOCKADDR_SA_LEN
 
+# AArch64 is bi-endian, but we require little
+if test x"$host_cpu" = x"aarch64"; then
+  if test x"$ac_cv_c_bigendian" = x"yes"; then
+    AC_MSG_ERROR([big endian is not supported for aarch64])
+  fi
+fi
+
 # MSVC doesn't cope well with defining restrict to __restrict, the
 # spelling it understands, because it conflicts with
 # __declspec(restrict). Therefore we define pg_restrict to the
diff --git a/meson.build b/meson.build
index 395416a6060..35f2580d8ef 100644
--- a/meson.build
+++ b/meson.build
@@ -1731,6 +1731,10 @@ endif
 ###############################################################
 
 if host_machine.endian() == 'big'
+  # AArch64 is bi-endian, but we require little
+  if host_cpu == 'aarch64'
+    error('big endian is not supported for aarch64')
+  endif
   cdata.set('WORDS_BIGENDIAN', 1)
 endif
 
-- 
2.39.5 (Apple Git-154)