[commit: ghc] wip/T13633: testsuite RTS: Add barrier to debug code (c470b8a)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/T13633
Link       : http://ghc.haskell.org/trac/ghc/changeset/c470b8ac5c7ef4eb97efe25c4c2bde1add7e60be/ghc

>---------------------------------------------------------------

commit c470b8ac5c7ef4eb97efe25c4c2bde1add7e60be
Author: Peter Trommler <ptrommler at acm.org>
Date:   Sun Feb 24 19:13:53 2019 +0100

    testsuite RTS: Add barrier to debug code


>---------------------------------------------------------------

c470b8ac5c7ef4eb97efe25c4c2bde1add7e60be
 testsuite/tests/rts/testwsdeque.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/testsuite/tests/rts/testwsdeque.c b/testsuite/tests/rts/testwsdeque.c
index 3f17f32..a21f9bd 100644
--- a/testsuite/tests/rts/testwsdeque.c
+++ b/testsuite/tests/rts/testwsdeque.c
@@ -51,7 +51,9 @@ myStealWSDeque_ (WSDeque *q, uint32_t n)
     if ((long)b - (long)t <= 0 ) { 
         return NULL; /* already looks empty, abort */
   }
-    
+    // NB. these loads must be ordered so writes from pushWSDeque
+    // will be seen.
+    load_load_barrier();
     /* now access array, see pushBottom() */
     stolen = q->elements[t & q->moduloSize];