re PR middle-end/59448 (Code generation doesn't respect C11 address-dependency)

2015-01-14  Andrew MacLeod  <amacleod@redhat.com>

	PR middle-end/59448
	* builtins.c (get_memmodel): Promote consume to acquire always.
	* testsuite/gcc.dg/atomic-invalid.c: Remove obselete test for illegal
	consume in an atomic_exchange.

From-SVN: r219601

gcc/ChangeLog

+2015-01-14  Andrew MacLeod  <amacleod@redhat.com>
+
+	PR middle-end/59448
+	* builtins.c (get_memmodel): Promote consume to acquire always.
+
 2014-01-14  Ilya Tocar  <ilya.tocar@intel.com>
 
 	PR target/64386

gcc/builtins.c

@@ -5365,6 +5365,11 @@ get_memmodel (tree exp)
       return MEMMODEL_SEQ_CST;
     }
 
+  /* Workaround for Bugzilla 59448. GCC doesn't track consume properly, so
+     be conservative and promote consume to acquire.  */
+  if (val == MEMMODEL_CONSUME)
+    val = MEMMODEL_ACQUIRE;
+
   return (enum memmodel) val;
 }
 

gcc/testsuite/ChangeLog

+2015-01-14  Andrew MacLeod  <amacleod@redhat.com>
+
+	PR middle-end/59448
+	* gcc.dg/atomic-invalid.c: Remove obselete test for illegal consume in
+	an atomic_exchange.
+
 2014-01-14  Ilya Tocar  <ilya.tocar@intel.com>
 
 	PR target/64386

gcc/testsuite/gcc.dg/atomic-invalid.c

@@ -17,8 +17,6 @@ main ()
   __atomic_compare_exchange_n (&i, &e, 1, 0, __ATOMIC_SEQ_CST, __ATOMIC_RELEASE); /* { dg-error "invalid failure memory" } */
   __atomic_compare_exchange_n (&i, &e, 1, 1, __ATOMIC_SEQ_CST, __ATOMIC_ACQ_REL); /* { dg-error "invalid failure memory" } */
 
-  __atomic_exchange_n (&i, 1, __ATOMIC_CONSUME); /* { dg-error "invalid memory model" } */
-
   __atomic_load_n (&i, __ATOMIC_RELEASE); /* { dg-error "invalid memory model" } */
   __atomic_load_n (&i, __ATOMIC_ACQ_REL); /* { dg-error "invalid memory model" } */