Fix a problematic logic at unswitch-loops pass.

2010-04-07  Jing Yu  <jingyu@google.com>
            Zdenek Dvorak  <ook@ucw.cz>

	PR tree-optimization/42720
	* tree-ssa-loop-unswitch.c (tree_ssa_unswitch_loops): Move one-time
	loop unswitch conditions here from
	(tree_unswitch_single_loop).


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@158138 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 25 deletions

diff --git a/gcc/tree-ssa-loop-unswitch.c b/gcc/tree-ssa-loop-unswitch.c
index 5b9ba90469c..bb3b1a5f40a 100644
--- a/gcc/tree-ssa-loop-unswitch.c
+++ b/gcc/tree-ssa-loop-unswitch.c
@@ -88,6 +88,26 @@ tree_ssa_unswitch_loops (void)
   /* Go through inner loops (only original ones).  */
   FOR_EACH_LOOP (li, loop, LI_ONLY_INNERMOST)
     {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+        fprintf (dump_file, ";; Considering loop %d\n", loop->num);
+
+      /* Do not unswitch in cold regions. */
+      if (optimize_loop_for_size_p (loop))
+        {
+          if (dump_file && (dump_flags & TDF_DETAILS))
+            fprintf (dump_file, ";; Not unswitching cold loops\n");
+          continue;
+        }
+
+      /* The loop should not be too large, to limit code growth. */
+      if (tree_num_loop_insns (loop, &eni_size_weights)
+          > (unsigned) PARAM_VALUE (PARAM_MAX_UNSWITCH_INSNS))
+        {
+          if (dump_file && (dump_flags & TDF_DETAILS))
+            fprintf (dump_file, ";; Not unswitching, loop too big\n");
+          continue;
+        }
+
       changed |= tree_unswitch_single_loop (loop, 0);
     }
 
@@ -189,31 +209,6 @@ tree_unswitch_single_loop (struct loop *loop, int num)
       return false;
     }
 
-  /* Only unswitch innermost loops.  */
-  if (loop->inner)
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, ";; Not unswitching, not innermost loop\n");
-      return false;
-    }
-
-  /* Do not unswitch in cold regions.  */
-  if (optimize_loop_for_size_p (loop))
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, ";; Not unswitching cold loops\n");
-      return false;
-    }
-
-  /* The loop should not be too large, to limit code growth.  */
-  if (tree_num_loop_insns (loop, &eni_size_weights)
-      > (unsigned) PARAM_VALUE (PARAM_MAX_UNSWITCH_INSNS))
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, ";; Not unswitching, loop too big\n");
-      return false;
-    }
-
   i = 0;
   bbs = get_loop_body (loop);