loop-iv.c (iv_number_of_iterations): Fix overflow check for loops that count down.

2005-08-31  Dale Johannesen  <dalej@apple.com>

        * loop-iv.c (iv_number_of_iterations):  Fix overflow check for
        loops that count down.

From-SVN: r103689

gcc/ChangeLog

+2005-08-31  Dale Johannesen  <dalej@apple.com>
+
+	* loop-iv.c (iv_number_of_iterations):  Fix overflow check for
+	loops that count down.
+
 2005-08-31  Richard Henderson  <rth@redhat.com>
 
 	PR rtl-opt/23601

gcc/loop-iv.c

@@ -2417,7 +2417,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
 	  tmp0 = lowpart_subreg (mode, iv0.base, comp_mode);
 	  tmp1 = lowpart_subreg (mode, iv1.base, comp_mode);
 
-	  bound = simplify_gen_binary (MINUS, mode, mode_mmin,
+	  bound = simplify_gen_binary (PLUS, mode, mode_mmin,
 				       lowpart_subreg (mode, step, comp_mode));
 	  if (step_is_pow2)
 	    {