From patchwork Thu Nov 29 21:12:28 2012
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Subject: [4.6] Fix PR libgcc/48076
Date: Thu, 29 Nov 2012 11:12:28 -0000
From: Richard Henderson <rth@redhat.com>
X-Patchwork-Id: 202826
Message-Id: <50B7CFBC.5010109@redhat.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>

A different fix is required for 4.6, because the __atomic
functions don't exist yet.


r~
PR libgcc/48076
        * emutls.c (__emutls_get_address): Add memory barrier before
        referencing emutls_key.


diff --git a/gcc/emutls.c b/gcc/emutls.c
index b7ee3bd..fcf6eb5 100644
--- a/gcc/emutls.c
+++ b/gcc/emutls.c
@@ -151,6 +151,9 @@ __emutls_get_address (struct __emutls_object *obj)
       __gthread_mutex_unlock (&emutls_mutex);
     }
 
+  /* Do not allow emutls_key to be loaded before offset.  */
+  __sync_synchronize();
+
   struct __emutls_array *arr = __gthread_getspecific (emutls_key);
   if (__builtin_expect (arr == NULL, 0))
     {