diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 71eb7007f46428ba0bbace4b7dcb3ece743c68d2..8da8006782b8b7262b149171084bcd790a3137de 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2006-01-19 Jeff Law <law@redhat.com>
+
+ * tree-vrp.c (extract_range_from_assert): Refine the result range
+ if the variable referenced by the ASSERT_EXPR has a range and
+ either the tentative result range or the previous range is a
+ VR_ANTI_RANGE.
+
2006-01-19 Richard Sandiford <richard@codesourcery.com>
* c-decl.c (add_flexible_array_elts_to_size): Simplify vector accesses.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4266cb0aa4a4dc8563dfb9f6b88c4f29af675e9f..ab86c53c028597459ce53396801151c71f4d5cf2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2006-01-18 Jeff Law <law@redhat.com>
+
+ * gcc.dg/tree-ssa/vrp25.c: New test.
+
2006-01-19 Richard Sandiford <richard@codesourcery.com>
* gcc.dg/pr25805.c: Fix misapplied patch.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp25.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp25.c
new file mode 100644
index 0000000000000000000000000000000000000000..52f9ea2fea54b9c5dcd2137ea4aa7d16fb014112
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp25.c
@@ -0,0 +1,52 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-vrp-details" } */
+
+extern void abort ();
+int tree_code_length[100];
+
+blah (int code1)
+{
+ unsigned char D18670;
+
+ if (code1 != 53) goto L0; else goto L1;
+
+L0:
+ abort ();
+
+L1:
+ D18670 = tree_code_length[53];
+ if (D18670 <= 1) goto L2; else goto L3;
+
+L2:
+ abort ();
+
+L3:
+ if (D18670 == 2) goto L4; else goto L5;
+
+L4:
+ abort ();
+
+L5:
+ arf ();
+ if (code1 != 53) goto L6; else goto L7;
+
+L6:
+ abort ();
+
+L7:
+ if (D18670 <= 2) goto L8; else goto L9;
+
+L8:
+ abort ();
+
+L9:
+ return;
+
+}
+
+/* The second test of (code1 != 53) and the test (D18670 <= 2) are
+ both totally subsumed by earlier tests and thus should be folded
+ away using VRP. */
+/* { dg-final { scan-tree-dump-times "Folding predicate" 2 "vrp" } } */
+/* { dg-final { cleanup-tree-dump "vrp" } } */
+
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index a5028b4d8f59862284c4bdaf568ee9d5c4cfceab..c4a921c50a9aea4c505b9fb2ca8961d5a3c31e3f 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1048,6 +1048,96 @@ extract_range_from_assert (value_range_t *vr_p, tree expr)
if (compare_values (var_vr->min, vr_p->min) == 0
&& compare_values (var_vr->max, vr_p->max) == 0)
set_value_range_to_varying (vr_p);
+ else
+ {
+ tree min, max, anti_min, anti_max, real_min, real_max;
+
+ /* We want to compute the logical AND of the two ranges;
+ there are three cases to consider.
+
+
+ 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.
+
+ 2. The VR_ANTI_RANGE is completely disjoint from
+ the VR_RANGE. In this case the resulting range
+ should be the VR_RANGE.
+
+ 3. There is some overlap between the VR_ANTI_RANGE
+ and the VR_RANGE.
+
+ 3a. If the high limit of the VR_ANTI_RANGE resides
+ within the VR_RANGE, then the result is a new
+ VR_RANGE starting at the high limit of the
+ the VR_ANTI_RANGE + 1 and extending to the
+ high limit of the original VR_RANGE.
+
+ 3b. If the low limit of the VR_ANTI_RANGE resides
+ within the VR_RANGE, then the result is a new
+ VR_RANGE starting at the low limit of the original
+ VR_RANGE and extending to the low limit of the
+ VR_ANTI_RANGE - 1. */
+ if (vr_p->type == VR_ANTI_RANGE)
+ {
+ anti_min = vr_p->min;
+ anti_max = vr_p->max;
+ real_min = var_vr->min;
+ real_max = var_vr->max;
+ }
+ else
+ {
+ anti_min = var_vr->min;
+ anti_max = var_vr->max;
+ real_min = vr_p->min;
+ real_max = vr_p->max;
+ }
+
+
+ /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
+ not including any endpoints. */
+ 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);
+ }
+ /* Case 2, VR_ANTI_RANGE completely disjoint from
+ VR_RANGE. */
+ else if (compare_values (anti_min, real_max) == 1
+ || compare_values (anti_max, real_min) == -1)
+ {
+ set_value_range (vr_p, VR_RANGE, real_min,
+ real_max, vr_p->equiv);
+ }
+ /* Case 3a, the anti-range extends into the low
+ part of the real range. Thus creating a new
+ low for the real reange. */
+ else if ((compare_values (anti_max, real_min) == 1
+ || compare_values (anti_max, real_min) == 0)
+ && compare_values (anti_max, real_max) == -1)
+ {
+ min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
+ anti_max,
+ build_int_cst (TREE_TYPE (var_vr->min), 1));
+ max = real_max;
+ set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
+ }
+ /* Case 3b, the anti-range extends into the high
+ part of the real range. Thus creating a new
+ higher for the real reange. */
+ else if (compare_values (anti_min, real_min) == 1
+ && (compare_values (anti_min, real_max) == -1
+ || compare_values (anti_min, real_max) == 0))
+ {
+ max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
+ anti_min,
+ build_int_cst (TREE_TYPE (var_vr->min), 1));
+ min = real_min;
+ set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
+ }
+ }
}
/* Remove names from the equivalence set that have ranges