[PATCH] Fix errors in expand_atomic_store.

[Richard Henderson]

        * optabs.c (expand_atomic_store): Use create_fixed_operand for
        atomic_store optab.  Don't try to fall back to sync_lock_release.

---
The create_fixed_operand thinko is obvious.  The sync_lock_release is
more subtle.  The target is allowed to support only storing 0/1 with
the test_and_set/lock_release pair, and it's allowed to support that
in non-obvious ways.  We don't want to get involved in that.


r~

---
 gcc/ChangeLog.mm |    5 +++++
 gcc/optabs.c     |   21 +--------------------
 2 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 1ecab53..d8ab97e 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -7118,32 +7118,13 @@ expand_atomic_store (rtx mem, rtx val, enum memmodel model)
   icode = direct_optab_handler (atomic_store_optab, mode);
   if (icode != CODE_FOR_nothing)
     {
-
-      create_output_operand (&ops[0], mem, mode);
+      create_fixed_operand (&ops[0], mem);
       create_input_operand (&ops[1], val, mode);
       create_integer_operand (&ops[2], model);
       if (maybe_expand_insn (icode, 3, ops))
 	return const0_rtx;
     }
 
-  /* A store of 0 is the same as __sync_lock_release, try that.  */
-  if (CONST_INT_P (val) && INTVAL (val) == 0)
-    {
-      icode = direct_optab_handler (sync_lock_release_optab, mode);
-      if (icode != CODE_FOR_nothing)
-	{
-	  create_fixed_operand (&ops[0], mem);
-	  create_input_operand (&ops[1], const0_rtx, mode);
-	  if (maybe_expand_insn (icode, 2, ops))
-	    {
-	      /* lock_release is only a release barrier.  */
-	      if (model == MEMMODEL_SEQ_CST)
-		expand_builtin_mem_thread_fence (model);
-	      return const0_rtx;
-	    }
-	}
-    }
-
   /* If the size of the object is greater than word size on this target,
      a default store will not be atomic, Try a mem_exchange and throw away
      the result.  If that doesn't work, don't do anything.  */
-- 
1.7.6.4