fold-const.c (make_range): When handling unsigned, don't reverse range if high bound is zero.

	* fold-const.c (make_range): When handling unsigned, don't reverse
	range if high bound is zero.

From-SVN: r71991

gcc/ChangeLog

+2003-10-01  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+	* fold-const.c (make_range): When handling unsigned, don't reverse
+	range if high bound is zero.
+
 2003-09-30  Alexandre Oliva  <aoliva@redhat.com>
 
 	config/frv/frv.h (PREDICATE_CODES): Added

gcc/fold-const.c

@@ -3076,10 +3076,10 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 
 	      in_p = n_in_p, low = n_low, high = n_high;
 
-	      /* If the high bound is missing, but we
-		 have a low bound, reverse the range so
-		 it goes from zero to the low bound minus 1.  */
-	      if (high == 0 && low)
+	      /* If the high bound is missing, but we have a non-zero low
+		 bound, reverse the range so it goes from zero to the low bound
+		 minus 1.  */
+	      if (high == 0 && low && ! integer_zerop (low))
 		{
 		  in_p = ! in_p;
 		  high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,