Re-commit r139643.

Make clang use Acquire loads and Release stores where necessary.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139650 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/atomic.c b/test/CodeGen/atomic.c
index a0adac8..c8f4fd0 100644
--- a/test/CodeGen/atomic.c
+++ b/test/CodeGen/atomic.c
@@ -75,8 +75,7 @@
   // CHECK: cmpxchg i32* null, i32 0, i32 0 seq_cst
   
   __sync_lock_release(&val);
-  // FIXME: WRONG!
-  // CHECK: store volatile i32 0, i32* 
+  // CHECK: store atomic {{.*}} release, align 4
   
   __sync_synchronize ();
   // CHECK: fence seq_cst
@@ -88,8 +87,7 @@
 void release_return(int *lock) {
   // Ensure this is actually returning void all the way through.
   return __sync_lock_release(lock);
-  // FIXME: WRONG!
-  // CHECK: store volatile i32 0, i32* 
+  // CHECK: store atomic {{.*}} release, align 4
 }