re PR middle-end/53616 (416.gamess in SPEC CPU 2006 miscompiled)

2012-07-24  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53616
	* tree-loop-distribution.c (ldist_gen): Do not change
	partition ordering when merging partitions.

From-SVN: r189802

gcc/ChangeLog

+2012-07-24  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/53616
+	* tree-loop-distribution.c (ldist_gen): Do not change
+	partition ordering when merging partitions.
+
 2012-07-24  Alan Modra  <amodra@gmail.com>
 
 	PR target/53914

gcc/tree-loop-distribution.c

@@ -1289,7 +1289,12 @@ ldist_gen (struct loop *loop, struct graph *rdg,
 	  nbp = 0;
 	  goto ldist_done;
 	}
-      for (i = 0; VEC_iterate (partition_t, partitions, i, into); ++i)
+      /* Only fuse adjacent non-builtin partitions, see PR53616.
+         ???  Use dependence information to improve partition ordering.  */
+      i = 0;
+      do
+	{
+	  for (; VEC_iterate (partition_t, partitions, i, into); ++i)
 	    if (!partition_builtin_p (into))
 	      break;
 	  for (++i; VEC_iterate (partition_t, partitions, i, partition); ++i)
@@ -1299,6 +1304,10 @@ ldist_gen (struct loop *loop, struct graph *rdg,
 		VEC_ordered_remove (partition_t, partitions, i);
 		i--;
 	      }
+	    else
+	      break;
+	}
+      while ((unsigned) i < VEC_length (partition_t, partitions));
     }
   else
     {