prefetch-5.c: xfail.

	* gcc.dg/tree-ssa/prefetch-5.c: xfail.
	* tree-ssa-loop-niter.c (idx_infer_loop_bounds): We can not produce
	realistic upper bounds here.

From-SVN: r236508

gcc/ChangeLog

+2016-05-20  Jan Hubicka  <hubicka@ucw.cz>
+
+	* tree-ssa-loop-niter.c (idx_infer_loop_bounds): We can not produce
+	realistic upper bounds here.
+
 2016-05-20  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/71210

gcc/testsuite/ChangeLog

+2016-05-20  Jan Hubicka  <hubicka@ucw.cz>
+
+	* gcc.dg/tree-ssa/prefetch-5.c: xfail.
+
 2016-05-20  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/71210

gcc/testsuite/gcc.dg/tree-ssa/prefetch-5.c

@@ -54,5 +54,7 @@ int loop5 (int n, struct tail5 *x)
   return s;
 }
 
-/* { dg-final { scan-tree-dump-times "Issued prefetch" 2 "aprefetch" } } */
-/* { dg-final { scan-tree-dump-times "Not prefetching" 1 "aprefetch" } } */
+/* Until we are able to track likely upper bounds, we can't really work out that
+   small trailing arrays should not be prefetched.  */
+/* { dg-final { scan-tree-dump-times "Issued prefetch" 2 "aprefetch" { xfail *-*-* } } } */
+/* { dg-final { scan-tree-dump-times "Not prefetching" 1 "aprefetch" { xfail *-*-* } } } */

gcc/tree-ssa-loop-niter.c

@@ -3115,7 +3115,6 @@ idx_infer_loop_bounds (tree base, tree *idx, void *dta)
   tree low, high, type, next;
   bool sign, upper = true, at_end = false;
   struct loop *loop = data->loop;
-  bool reliable = true;
 
   if (TREE_CODE (base) != ARRAY_REF)
     return true;
@@ -3187,14 +3186,14 @@ idx_infer_loop_bounds (tree base, tree *idx, void *dta)
       && tree_int_cst_compare (next, high) <= 0)
     return true;
 
-  /* If access is not executed on every iteration, we must ensure that overlow may
-     not make the access valid later.  */
+  /* If access is not executed on every iteration, we must ensure that overlow
+     may not make the access valid later.  */
   if (!dominated_by_p (CDI_DOMINATORS, loop->latch, gimple_bb (data->stmt))
       && scev_probably_wraps_p (initial_condition_in_loop_num (ev, loop->num),
 				step, data->stmt, loop, true))
-    reliable = false;
+    upper = false;
 
-  record_nonwrapping_iv (loop, init, step, data->stmt, low, high, reliable, upper);
+  record_nonwrapping_iv (loop, init, step, data->stmt, low, high, false, upper);
   return true;
 }