tree-vrp.c (compare_ranges): Return false for EQ_EXPR if VR0 is less than VR1 or vice-versa.

2005-11-19  James A. Morrison  <phython@gcc.gnu.org>

        * tree-vrp.c (compare_ranges): Return false for EQ_EXPR if VR0 is less
        than VR1 or vice-versa.

From-SVN: r107243

gcc/ChangeLog

+2005-11-19  James A. Morrison  <phython@gcc.gnu.org>
+
+        * tree-vrp.c (compare_ranges): Return false for EQ_EXPR if VR0 is less
+        than VR1 or vice-versa.
+
 2005-11-19  Hans-Peter Nilsson  <hp@axis.com>
 
 	PR middle-end/24912

gcc/testsuite/ChangeLog

+2005-11-19  James A. Morrison  <phython@gcc.gnu.org>
+
+	* gcc.dg/tree-ssa/vrp22.c: New test.
+
 2005-11-19  Hans-Peter Nilsson  <hp@axis.com>
 
 	PR middle-end/24912

gcc/testsuite/gcc.dg/tree-ssa/vrp22.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -ftree-vrp -fdump-tree-vrp" } */
+
+extern void link_error ();
+
+void test02(unsigned int a, unsigned int b)
+{
+  unsigned int x = 0x80000000;
+  if (a > x)
+    if (b < x)
+      if (a == b)
+        link_error ();
+}
+
+/* { dg-final { scan-tree-dump-times "link_error" 0 "vrp" } } */
+/* { dg-final { cleanup-tree-dump "vrp" } } */

gcc/tree-vrp.c

@@ -1878,6 +1878,10 @@ compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1)
 	  else if (cmp_min != -2 && cmp_max != -2)
 	    return boolean_false_node;
 	}
+      /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1.  */
+      else if (compare_values (vr0->min, vr1->max) == 1
+	       || compare_values (vr1->min, vr0->max) == 1)
+	return boolean_false_node;
 
       return NULL_TREE;
     }