Add 3 new EVRP testcases.

test new evrp functionality.

	gcc/testsuite/
	* gcc.dg/tree-ssa/evrp20.c
	* gcc.dg/tree-ssa/evrp21.c
	* gcc.dg/tree-ssa/evrp22.c

gcc/testsuite/gcc.dg/tree-ssa/evrp20.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+void call (void);
+
+void foo (int base)
+{
+  unsigned i;
+
+  // Ranger should be able to remove the (i > 123) comparison.
+  for (i = base; i < 10; i++)
+    if (i > 123)
+      {
+        call ();
+	return;
+      }
+}
+
+/* { dg-final { scan-tree-dump-not "call" "evrp"} } */

gcc/testsuite/gcc.dg/tree-ssa/evrp21.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+extern void vrp_keep (void);
+extern void vrp_kill (void);
+
+void
+f2 (int s, int b)
+{
+  if (s > 4)
+    s = 4;
+  if (s < -16)
+    s = -16;
+  /* s in [-16, 4].   */
+  b = (b & 1) + 1;
+  /* b in range [1, 2].  */
+  b = s << b;
+  /* b in range [-64, 16].  */
+  if (b == -2)
+    vrp_keep ();
+  if (b <= -65)
+    vrp_kill ();
+  if (b >= 17)
+    vrp_kill ();
+}
+
+/* { dg-final { scan-tree-dump-times "vrp_keep \\(" 1 "evrp"} } */
+/* { dg-final { scan-tree-dump-times "vrp_kill \\(" 0 "evrp"} } */

gcc/testsuite/gcc.dg/tree-ssa/evrp22.c

+/* See backwards thru casts if the range fits the LHS type. */
+/* { dg-do compile } */
+/* { dg-options "-O2  -fdump-tree-evrp" } */
+
+extern void kill(int i);
+extern void keep(int i);
+
+void
+foo (int i)
+{
+  if (i >= 10)
+    {
+      if (i <= 100)
+	{
+	  /* i has a range of [10, 100]  */
+	  char c = (char) i;
+	  if (c < 30)
+	    {
+	      /* If we wind back thru the cast with the range of c being [10,29]
+	       * from the branch, and recognize that the range of i fits within
+	       * a cast to c, then there is no missing information in a cast
+	       * back to int. We can use the range calculated for 'c' with 'i'
+	       * as well and Ranger should be able to kill the call.  */
+	      if (i > 29)
+		kill (i);
+	    }
+	}
+      /* i has a range of [10, MAX]  */
+      char d  = (char) i;
+      if (d < 30)
+	{
+	  /* Here, a cast to a char and back is NOT equivalent, so we cannot use
+	   * the value of d to remove the call.  */
+	  if (i > 29)
+	    keep (i);
+	}
+
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "kill \\(" 0 "evrp"} } */
+/* { dg-final { scan-tree-dump-times "keep \\(" 1 "evrp"} } */
+