(make_range, comparison cases): When making range for unsigned to

merge in, use full range.

From-SVN: r13027

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 2af2f8b2cc37220ec552d6b1873afd6f8a012578..cb45cd28ee2519aa2eed712f2c0cf766ec1a9f3b 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -2757,15 +2757,20 @@ make_range (exp, pin_p, plow, phigh)
 
          exp = arg0;
 
-         /* If this is an unsigned comparison, we also know that EXP
-            is greater than or equal to zero.  We base the range tests
-            we make on that fact, so we record it here so we can parse
-            existing range tests.  */
-         if (TREE_UNSIGNED (type))
+         /* If this is an unsigned comparison, we also know that EXP is
+            greater than or equal to zero and less than the maximum value of
+            the unsigned type.  We base the range tests we make on that fact,
+            so we record it here so we can parse existing range tests.  */
+         if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
            {
              if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
                                  1, convert (type, integer_zero_node),
-                                 NULL_TREE))
+                                 const_binop (MINUS_EXPR,
+                                              convert (type,
+                                                       integer_zero_node),
+                                              convert (type,
+                                                       integer_one_node),
+                                              0)))
                break;
 
              in_p = n_in_p, low = n_low, high = n_high;