PR ada/25900

	* tree-vrp.c (extract_range_from_assert): When merging a VR_RANGE
	with a VR_ANTI_RANGE and the VR_ANTI_RANGEis completely contained
	within the VR_RANGE, use the VR_RANGE as the result, not the
	VR_ANTI_RANGE.
	(adjust_range_with_scev): Reject ranges from SCEV which are out
	of bounds for the type.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@110261 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 91175a9..738efd7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,14 @@
-2006-01-26  Daniel Berlin  <dberlin@dberlin.org>
+2006-01-26  Jeff Law  <law@redhat.com>
+
+       PR ada/25900
+       * tree-vrp.c (extract_range_from_assert): When merging a VR_RANGE
+       with a VR_ANTI_RANGE and the VR_ANTI_RANGEis completely contained
+       within the VR_RANGE, use the VR_RANGE as the result, not the
+       VR_ANTI_RANGE.
+       (adjust_range_with_scev): Reject ranges from SCEV which are out
+       of bounds for the type.
+
+2005-01-26  Daniel Berlin  <dberlin@dberlin.org>
 
        * tree-ssa-alias.c (maybe_create_global_var): Change
        subvar walking to an assertion that we don't have subvar'd variables.

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index c4a921c..843518e 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1059,7 +1059,8 @@ extract_range_from_assert (value_range_t *vr_p, tree expr)
             1. The VR_ANTI_RANGE range is competely within the 
                VR_RANGE and the endpoints of the ranges are
                different.  In that case the resulting range
-               should be the VR_ANTI_RANGE.
+               should be whichever range is more precise.
+               Typically that will be the VR_RANGE.
 
             2. The VR_ANTI_RANGE is completely disjoint from
                the VR_RANGE.  In this case the resulting range
@@ -1100,8 +1101,8 @@ extract_range_from_assert (value_range_t *vr_p, tree expr)
          if (compare_values (anti_max, real_max) == -1
              && compare_values (anti_min, real_min) == 1)
            {
-             set_value_range (vr_p, VR_ANTI_RANGE, anti_min,
-                              anti_max, vr_p->equiv);
+             set_value_range (vr_p, VR_RANGE, real_min,
+                              real_max, vr_p->equiv);
            }
          /* Case 2, VR_ANTI_RANGE completely disjoint from
             VR_RANGE.  */
@@ -1918,12 +1919,21 @@ adjust_range_with_scev (value_range_t *vr, struct loop *loop, tree stmt,
     {
       /* For VARYING or UNDEFINED ranges, just about anything we get
         from scalar evolutions should be better.  */
+      tree min = TYPE_MIN_VALUE (TREE_TYPE (init));
+      tree max = TYPE_MAX_VALUE (TREE_TYPE (init));
+
       if (init_is_max)
-       set_value_range (vr, VR_RANGE, TYPE_MIN_VALUE (TREE_TYPE (init)),
-                        init, vr->equiv);
+       max = init;
       else
-       set_value_range (vr, VR_RANGE, init, TYPE_MAX_VALUE (TREE_TYPE (init)),
-                        vr->equiv);
+       min = init;
+
+      /* If we would create an invalid range, then just assume we
+        know absolutely nothing.  This may be over-conservative,
+        but it's clearly safe.  */
+      if (compare_values (min, max) == 1)
+       return;
+
+      set_value_range (vr, VR_RANGE, min, max, vr->equiv);
     }
   else if (vr->type == VR_RANGE)
     {