re PR tree-optimization/80304 (Wrong result with do concurrent)

2017-04-10  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80304
	* tree-ssa-loop-im.c (ref_indep_loop_p_1): Also recurse
	for safelen.

	* gcc.dg/torture/pr80304.c: New testcase.

From-SVN: r246803

gcc/ChangeLog

+2017-04-10  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80304
+	* tree-ssa-loop-im.c (ref_indep_loop_p_1): Also recurse
+	for safelen.
+
 2017-04-10  Nathan Sidwell  <nathan@acm.org>
 
 	PR target/79905

gcc/testsuite/ChangeLog

+2017-04-10  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80304
+	* gcc.dg/torture/pr80304.c: New testcase.
+
 2017-04-10  Nathan Sidwell  <nathan@acm.org>
 
 	PR target/79905

gcc/testsuite/gcc.dg/torture/pr80304.c

+/* { dg-do run } */
+
+int __attribute__((pure,noinline,noclone)) foo (int *p)
+{
+  return *p * 2;
+}
+
+int main()
+{
+  int k = 0;
+  int i;
+#pragma GCC ivdep
+  for (k = 0; k < 9;)
+    {
+      i = 0;
+      while (1)
+	{
+	  k += foo (&i);
+	  if (k > 7)
+	    break;
+	  i++;
+	}
+    }
+  if (k != 12)
+    __builtin_abort ();
+  return 0;
+}

gcc/tree-ssa-loop-im.c

@@ -2145,9 +2145,21 @@ ref_indep_loop_p_1 (int safelen, struct loop *loop, im_mem_ref *ref,
 	  fprintf (dump_file, "\n");
 	}
 
+      /* We need to recurse to properly handle UNANALYZABLE_MEM_ID.  */
+      struct loop *inner = loop->inner;
+      while (inner)
+	{
+	  if (!ref_indep_loop_p_1 (safelen, inner, ref, stored_p, ref_loop))
+	    {
+	      indep_p = false;
+	      break;
+	    }
+	  inner = inner->next;
+	}
+
       /* Avoid caching here as safelen depends on context and refs
          are shared between different contexts.  */
-      return true;
+      return indep_p;
     }
   else
     {