From f843e215f3f640de377d8fd60e85bb372fb138fd Mon Sep 17 00:00:00 2001
From: Tzachi Zidenberg <tsahee@amazon.com>
Date: Sun, 5 Jul 2020 15:21:43 +0300
Subject: [PATCH] aarch64: use compiler flag outline-atomics if available

outline-atomics compilation flag changes behaviour of builtin_atomics,
by adding runtime detection of LSE atomics. If these are supported, they
will be used. This gains LSE atomics use without hurting compatibility
with older aarch64 machines.
---
 configure.cmake | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/configure.cmake b/configure.cmake
index 43c32fda0ee..5dd45a6b05d 100644
--- a/configure.cmake
+++ b/configure.cmake
@@ -69,6 +69,11 @@ IF(CMAKE_SYSTEM_PROCESSOR STREQUAL "i686" AND CMAKE_COMPILER_IS_GNUCC AND
   SET(PLUGIN_QUERY_RESPONSE_TIME NO CACHE BOOL "Disabled, gcc is too old")
 ENDIF()
 
+# use runtime atomic-support detection in aarch64
+IF(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
+  MY_CHECK_AND_SET_COMPILER_FLAG("-moutline-atomics")
+ENDIF()
+
 IF(WITHOUT_DYNAMIC_PLUGINS)
   MESSAGE("Dynamic plugins are disabled.")
 ENDIF(WITHOUT_DYNAMIC_PLUGINS)