[Bug libstdc++/120567] [16 Regression] std::stacktrace tests now fail on arm-eabi

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120567

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I assume so - I don't think we changed anything that would fix it.

I should probably do this:

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index e4eb773144af..da5bc2b089b8 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -5316,7 +5316,7 @@ EOF

     AC_MSG_CHECKING([for atomic builtins for libbacktrace])
     if AC_TRY_EVAL(ac_compile); then
-      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
+      if grep -E '__atomic_|__sync_' conftest.s >/dev/null 2>&1 ; then
        glibcxx_cv_libbacktrace_atomics=no
       else
        glibcxx_cv_libbacktrace_atomics=yes
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index b1e1275c47f4..8c1c12823ec8 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -53996,7 +53996,7 @@ $as_echo_n "checking for atomic builtins for
libbacktrace... " >&6; }
   ac_status=$?
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; then
-      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
+      if grep -E '__atomic_|__sync_' conftest.s >/dev/null 2>&1 ; then
        glibcxx_cv_libbacktrace_atomics=no
       else
        glibcxx_cv_libbacktrace_atomics=yes


So that we treat extern calls to __sync_synchronize as "no native atomics".