[PATCH v2 2/2] libstdc++: Add dg-require-thread-fence in several tests

[Christophe Lyon]

Some targets like arm-eabi with newlib and default settings rely on
__sync_synchronize() to ensure synchronization.  Newlib does not
implement it by default, to make users aware they have to take special
care.

This makes a few tests fail to link.

This patch requires the missing thread-fence effective target in the
tests that need it, making them UNSUPPORTED instead of FAIL and
UNRESOLVED.

2023-09-10  Christophe Lyon  <christophe.lyon@linaro.org>

	libstdc++-v3/
	* testsuite/29_atomics/atomic/compare_exchange_padding.cc: Likewise.
	* testsuite/29_atomics/atomic/cons/value_init.cc: Likewise.
	* testsuite/29_atomics/atomic_float/value_init.cc: Likewise.
	* testsuite/29_atomics/atomic_integral/cons/value_init.cc: Likewise.
	* testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc: Likewise.
	* testsuite/29_atomics/atomic_ref/generic.cc: Likewise.
	* testsuite/29_atomics/atomic_ref/integral.cc: Likewise.
	* testsuite/29_atomics/atomic_ref/pointer.cc: Likewise.
---
 .../testsuite/29_atomics/atomic/compare_exchange_padding.cc      | 1 +
 libstdc++-v3/testsuite/29_atomics/atomic/cons/value_init.cc      | 1 +
 libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc     | 1 +
 .../testsuite/29_atomics/atomic_integral/cons/value_init.cc      | 1 +
 .../testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc  | 1 +
 libstdc++-v3/testsuite/29_atomics/atomic_ref/generic.cc          | 1 +
 libstdc++-v3/testsuite/29_atomics/atomic_ref/integral.cc         | 1 +
 libstdc++-v3/testsuite/29_atomics/atomic_ref/pointer.cc          | 1 +
 8 files changed, 8 insertions(+)

diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/compare_exchange_padding.cc b/libstdc++-v3/testsuite/29_atomics/atomic/compare_exchange_padding.cc
index c4ab876db2a..2e7ff0307bc 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic/compare_exchange_padding.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/compare_exchange_padding.cc
@@ -1,5 +1,6 @@
 // { dg-options "-std=gnu++20" }
 // { dg-do run { target c++20 } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/cons/value_init.cc b/libstdc++-v3/testsuite/29_atomics/atomic/cons/value_init.cc
index 47d5a5d5b28..b8019486ccf 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic/cons/value_init.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/cons/value_init.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 
 #include <atomic>
 
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc b/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
index 1cd1efb5422..6e89f2fc2a8 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_integral/cons/value_init.cc b/libstdc++-v3/testsuite/29_atomics/atomic_integral/cons/value_init.cc
index 96615a7d09f..2f6a48d36d8 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_integral/cons/value_init.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_integral/cons/value_init.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 
 #include <atomic>
 #include <testsuite_hooks.h>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc
index 0dab8a23e10..8469ebf8a14 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/compare_exchange_padding.cc
@@ -1,5 +1,6 @@
 // { dg-options "-std=gnu++20" }
 // { dg-do run { target c++20 } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/generic.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/generic.cc
index 14f417d1739..adae07f8754 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/generic.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/generic.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/integral.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/integral.cc
index e03ca921eb9..a98adb7fbba 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/integral.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/integral.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/pointer.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/pointer.cc
index 8cd0e124986..b9c7d844b8c 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/pointer.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/pointer.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-require-thread-fence "" }
 // { dg-add-options libatomic }
 
 #include <atomic>
-- 
2.34.1