re PR middle-end/42577 (array bounds false positive with -O3, goes away with -O2)

2010-01-02  Richard Guenther  <rguenther@suse.de>

	PR middle-end/42577
	* tree-vrp.c (check_all_array_refs): Skip non-excutable blocks.
	(simplify_switch_using_ranges): Mark to be removed edges
	as non-executable.

From-SVN: r155577

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4e32c542ac89fd966d99ad327003e34cb061bd62..93890c6d628502f9779fd6e46a5023d0e50eaf9a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2010-01-02  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/42577
+       * tree-vrp.c (check_all_array_refs): Skip non-excutable blocks.
+       (simplify_switch_using_ranges): Mark to be removed edges
+       as non-executable.
+
 2010-01-02  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
        * config/pa/t-slibgcc-dwarf-ver (SHLIB_SOVERSION): Bump by two.

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 2d0761b15faacc7ecce10d13ef9ca7d176daa8e2..c1ba16a04c2bd255427e7180a32f17c80ad92a8f 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -5122,36 +5122,16 @@ check_all_array_refs (void)
 
   FOR_EACH_BB (bb)
     {
-      /* Skip bb's that are clearly unreachable.  */
-      if (single_pred_p (bb))
-      {
-       int i;
-       bool reachable = true;
-       edge e2;
-       edge e = EDGE_PRED (bb, 0);
-       basic_block pred_bb = e->src;
-       gimple ls = NULL;
-
-       for (i = 0; VEC_iterate (edge, to_remove_edges, i, e2); ++i)
-         if (e == e2)
-           {
-             reachable = false;
-             break;
-           }
-
-       if (!reachable)
-         continue;
+      edge_iterator ei;
+      edge e;
+      bool executable = false;
 
-       if (!gsi_end_p (gsi_last_bb (pred_bb)))
-         ls = gsi_stmt (gsi_last_bb (pred_bb));
+      /* Skip blocks that were found to be unreachable.  */
+      FOR_EACH_EDGE (e, ei, bb->preds)
+       executable |= !!(e->flags & EDGE_EXECUTABLE);
+      if (!executable)
+       continue;
 
-       if (ls && gimple_code (ls) == GIMPLE_COND
-           && ((gimple_cond_false_p (ls)
-                && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
-               || (gimple_cond_true_p (ls)
-                   && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
-         continue;
-      }
       for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
        {
          gimple stmt = gsi_stmt (si);
@@ -6926,6 +6906,7 @@ simplify_switch_using_ranges (gimple stmt)
          fprintf (dump_file, "removing unreachable case label\n");
        }
       VEC_safe_push (edge, heap, to_remove_edges, e);
+      e->flags &= ~EDGE_EXECUTABLE;
     }
 
   /* And queue an update for the stmt.  */
@@ -7255,7 +7236,7 @@ vrp_finalize (void)
   substitute_and_fold (single_val_range, vrp_fold_stmt);
 
   if (warn_array_bounds)
-      check_all_array_refs ();
+    check_all_array_refs ();
 
   /* We must identify jump threading opportunities before we release
      the datastructures built by VRP.  */